Article

Ambient air SO2 patterns in 6 European cities

Authors:
  • Spanish National Research Council, in Barcelona, Spain
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Abstract

Introduction: An analysis of the hourly SO2 pollution patterns with time can be a useful tool for policy makers and stakeholders in developing more effective local policies in relation to air quality as it facilitates a deeper understanding of concentrations and potential source apportionment. A detailed analysis of hourly inter-annual, seasonal and weekday-specific SO2 concentration patterns using data obtained from 6 cities involved in the Aphekom project was conducted. This type of analysis has been done for other pollutants but less so for SO2, and not in a systematic fashion for a number of European cities. Methods: Individual diurnal SO2 profiles and working weekday versus weekend specific 24-hr plots were generated using hourly SO2 measurements from a roadside and an urban background monitoring sites for 1993, 2001 and 2009 for each of the 6 European cities (Athens, Barcelona, Brussels, London, Paris, and Vienna). This facilitated the assessment of city specific patterns and comparison of changes with time. Results: SO2 concentrations varied throughout the day and tended to be lower on the weekends. A general decreasing trend for SO2 levels with time was observable at all stations. Discussion & Conclusion: This study provides a useful European perspective on patterns of exposure. For the 6 EU cities examined, road traffic, heating, and shipping in port cities appeared to be important sources of SO2 emissions, and hence the driving components widely reflected in the diurnal profiles with lower levels on the weekend likely due to lower traffic volume and industry related emissions. Although ambient SO2 concentrations have fallen over the assessed study period at all measurement sites, the daily patterns remained relatively unchanged.

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... In addition to designated AQZs, the directive requires at least one monitor for PM 2.5 in every 100,000 km 2. Low emission zones (LEZs) were established in more than 200 European cities that enforced restrictions on cars and heavy-duty vehicles (Holman et al., 2015). The drawback of LEZs is that the zones were established based on city boundaries and not on geophysical features (Henschel et al., 2013). Turkey followed the European Directive to define AQZs for eight different regional areas within its 81 provinces (CYGM, 2010). ...
... Sulfur dioxide (SO 2 ) was use as a pollutant for the virtual sources due to the extensive data already collected by local air monitoring stations and heavy use of sulfur rich fuels in local combustion processes (Al-Awadhi, 2014;Al-Rashidi et al., 2005). SO 2 was also used for other studies involving air control zones (Hao et al., 2000;Henschel et al., 2013;Pereira et al., 2007). While photochemistry is an important process in secondary formation of pollutants, it is not important to the evaluation of dispersion and recirculation of pollutants in the AQZ. ...
... The model is based only on runs accomplished with SO 2 over an annual average of 8,760 hours. Different studies using ambient air measurements over time have assumed normal distributions of measurements and included statistics such as the mean and standard deviation (Henschel et al., 2013;Rivera-González et al., 2015;Suresh and Desa, 2005). For highly skewed data sets, traditional statistics cannot effectively describe the distribution. ...
Air quality zones are used by regulatory authorities to implement ambient air standards in order to protect human health. Air quality measurements at discrete air monitoring stations are critical tools to determine whether an air quality zone complies with local air quality standards or is non-compliant. This study presents a novel approach for evaluation of air quality zone classification methods by breaking the concentration distribution of a pollutant measured at an air monitoring station into compliance and exceedance Probability Density Functions (PDFs) and then using a Monte Carlo Analysis with the Central Limit Theorem to estimate long term exposure. The purpose of this paper is to compare the risk associated with selecting one ambient air classification approach over another by testing the possible exposure an individual living within a zone may face. The chronic daily intake (CDI) is utilized to compare different pollutant exposures over the classification duration of three years between two classification methods. Historical data collected from air monitoring stations in Kuwait are used to build representative models of 1 hr NO2 and 8 hr O3 within a zone that meets the compliance requirements of each method. The first method, the “3 Strike” method, is a conservative approach based on a winner-take-all approach common with most compliance classification methods, while the second, or 99% Rule method, allows for more robust analyses and incorporates long term trends. A Monte Carlo analysis is used to model the CDI for each pollutant and each method with the zone at a single station and with multiple stations. The model assumes that the zone is already in compliance with air quality standards over the three years under the different classification methodologies. The model shows that while the CDI of both methods differ by 2.7% over the exposure period for the single station case, the large number of samples taken over the duration period impact the sensitivity of the statistical tests, causing the Null hypothesis to fail. Local air quality managers can use either methodology to classify the compliance of an air zone, but must accept that the 99% Rule method may cause exposures that are statistically more significant than the 3 Strike method. Implications A novel method using the Central Limit Theorem and Monte Carlo Analysis is used to directly compare different air standard compliance classification methods by estimating the chronic daily intake of pollutants. This method allows air quality managers to rapidly see how individual classification methods may impact individual population groups, as well as evaluate different pollutants based on dosage and exposure when complete health impacts are not known.
... Canoas showed higher records during the cold months, mainly between 10:00 and 17:00 h. Probably, due to the increased occurrence of NW and W winds during the cold months, which would be responsible for the mobiles sources plume dispersion coming from the BR-116 highway over the sampling site, beyond the emissions of the REFAP Oil refinery (Henschel et al. 2013). Charqueadas showed similar values between winter and summer, indicating that the main local sources emit SO 2 continuously and evenly throughout the year. ...
... Differences between SO 2 concentrations during weekends/weekdays can be attributed to traffic emissions rush hour, because the highway is located near the stations for Esteio and Canoas Agudelo-Castañeda et al., 2014). These results are consistent with the wind rose presented by several authors (Morawska et al. 2008;Chen et al. 2010;Henschel et al. 2013) and their link with traffic emissions originating from highways located near the sampling station (Pasquier and André 2017). In addition, SO 2 originated from industrial and commercial activities is more emitted on weekdays, as observed in Esteio (Alizadeh-Choobari et al. 2016). ...
... Both sites are located downstream of the prevailing wind of Termochar (westnorthwest), consequently the similar pattern and SO 2 concentrations. These trends differ with other published trends in SO 2 levels around the world, where concentrations are decreasing (Henschel et al. 2013). More scientific research is needed for supporting the policies that should closely be linked to reduction potential and costs that are, in turn, substantially linked with local industrial and economic structures (Kanada et al. 2013). ...
Article
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Sulfur dioxide (SO2) is considered the most widespread pollutant that threatens environmental and human health. The purpose of this study is to propose a new method for evaluating the spatial variation of SO2 levels in the Metropolitan Area of Porto Alegre (MAPA). This method included use of Chi-square test to better identify the origin of SO2 sources. Additionally, results of the different methods applied allowed to analyze the temporal SO2 levels and their association with meteorological parameters. SO2 at five sampling sites (Esteio, Canoas, Charqueadas, Triunfo, and Gravataí) were measured during 2010–2015; using fluorescence SO2 automated analyzers. Results showed that Charqueadas had the highest average concentration (~ 15 μg m⁻³), followed by Triunfo (13 μg m⁻³), Esteio (6 μg m⁻³), Canoas (3 μg m⁻³), and Gravataí (2 μg m⁻³). Chi-square test applied to SO2, and wind direction quadrants showed significant contribution of local emission sources. Seasonal variation revealed higher SO2 levels on cold days for most of the studied sites, except for Esteio site. Day-wise variations revealed higher SO2 concentration on weekdays than weekends for Esteio and Canoas sites, indicating traffic influence especially during the rush-hours. Annual averages analysis identified an increasing trend in SO2 concentrations, implying that applied emission control systems and technological improvement of engines and fuels were not sufficient and thus points out a need for better subsidies mechanisms to pollutant control and effective emission reduction strategies that decision makers, including environmental agencies, must make priority by considering the local realities.
... Low emission zones (LEZs) were established in more than 200 European cities that enforced restrictions on cars and heavy-duty vehicles (Holman et al., 2015). The drawback of LEZs is that the zones were established based on city boundaries and not on geophysical features (Henschel et al., 2013). ...
... Sulfur dioxide (SO 2 ) was use as a pollutant for the virtual sources due to the extensive data already collected by local air monitoring stations and heavy use of sulfur rich fuels in local combustion processes (Al-Awadhi, 2014;Al-Rashidi et al., 2005). SO 2 was also used for other studies involving air control zones (Hao et al., 2000;Henschel et al., 2013;Pereira et al., 2007). While photochemistry is an important process in secondary formation of pollutants, it is not important to the evaluation of dispersion and recirculation of pollutants in the AQZ. ...
... Different studies using ambient air measurements over time have assumed normal distributions of measurements and included statistics such as the mean and standard deviation (Henschel et al., 2013;Rivera-González et al., 2015;Suresh and Desa, 2005). For highly skewed data sets, traditional statistics cannot effectively describe the distribution. ...
Article
Full-text available
This study presents a new method that incorporates modern air dispersion models allowing local terrain and land-sea breeze effects to be considered along with political and natural boundaries for more accurate mapping of air quality zones for coastal urban centers. This method uses local coastal wind patterns and key urban air pollution sources in each zone to more accurately calculate air pollutant concentration statistics. The new approach distributes virtual air pollution sources within each small grid cells of an area of interest and analyzes a puff dispersion model for a full year’s worth of one-hour prognostic weather data. The difference of wind patterns in coastal and inland areas create significantly different skewness (S) and kurtosis (K) statistics for the annually averaged pollutant concentrations at ground level receptor points for each grid cell. Plotting the S-K data highlights grouping of sources predominantly impacted by coastal winds versus inland winds. The application of the new method is demonstrated through a case study for the State of Kuwait by developing new AQZs to support local air management programs. The zone boundaries established by the S-K method were validated by comparing MM5 and WRF prognostic meteorological weather data used in the air dispersion modeling, a support vector machine classifier was trained to compare results with the graphical classification method, and final zones were compared with data collected from Earth observation satellites to confirm locations of high exposure risk areas. The resulting AQZs are more accurate and support efficient management strategies for air quality compliance targets effected by local coastal micro-climates. Implications A novel method to determine air quality zones in coastal urban areas is introduced using skewness (S) and kurtosis (K) statistics calculated from grid concentrations results of air dispersion models. The method identifies land-sea breeze effects that can be used to manage local air quality in areas of similar micro-climates. Keywords: Air quality, zones, coastal winds, land-sea breeze, remote sensing, Kuwait
... For the urban background sites (Fig. 2b) important SO 2 concentrations were registered in Athens, Thessaloniki and Madrid attributed mainly to domestic heating emissions as in Athens and Thessaloniki fuel oil boilers are the predominant heating system (Kassomenos , 2011). However, the observed values were significantly lower than the established limit value (125 μg m − 3 ) as a result of the adopted measures to reduce the sulfur content in fuels, coupled with the shift towards the use of cleaner fuels and the improvement of the efficiency of engines (Henschel et al., 2013). The highest O 3 levels were recorded in Athens (annual average reached 87 μg m − 3 at the urban background site and 78 μg m − 3 at the traffic site) as a consequence of the hot and dry summers that lead to elevated O 3 concentrations. ...
... In the sites where longer time series were available (from 5 to 8 years of continuous data), as for Barcelona, Madrid, Marseille and Rome the average SO 2 reduction ranged from −0.1 to −0.9 μg m −3 per year. This declining trend was the result of the various EU legislations being implemented in the respective cities, such as the EU Council Directive 2001/80/EC on the limitation of emissions from large combustion plants and the Directive 1999/32/EC limiting sulfur content in fuels for ships (Henschel et al., 2013). Furthermore, some local actions to reduce the use of sulfur-containing fuels as the reduction of the use of coal for domestic heating in Madrid have also contributed to this declining trend. ...
Article
Previous studies reported significant variability of air pollutants across Europe with the lowest concentrations generally found in Northern Europe and the highest in Southern European countries. Within the MED-PARTICLES project the spatial and temporal variations of long-term PM and gaseous pollutants data were investigated in traffic and urban background sites across Southern Europe. The highest PM levels were observed in Greece and Italy (Athens, Thessaloniki, Turin and Rome) while all traffic sites showed high NO2 levels, frequently exceeding the established limit value. High PM2.5/PM10 ratios were calculated indicating that fine particles comprise a large fraction of PM10, with the highest values found in the urban background sites. It seems that although in traffic sites the concentrations of both PM2.5 and PM10 are significantly higher than those registered in urban background sites, the coarse fraction PM2.5–10 is more important at the traffic sites. This fact is probably due to the high levels of resuspended road dust in sites highly affected by traffic, a phenomenon particularly relevant for Mediterranean countries. The long-term trends of air pollutants revealed a significant decrease of the concentration levels for PM, SO2 and CO while for NO2 no clear trend or slightly increasing trends were observed. This reduction could be attributed to the effectiveness of abatement measures and strategies and also to meteorological conditions and to the economic crisis that affected Southern Europe.
... The sources of energy are coal, fuel oil and diesel combustion. A passive sampling study made by Cuesta-Mosquera, González-Duque, Velasco-García, and Aristizábal (2018) Bimodal patterns in trace gases can be found in urban areas were traffic, industry and domestic heating are identified as SO 2 sources (Henschel et al., 2013;Hosseiniebalam & Ghaffarpasand, 2015;Syafei, Fujiwara, & Zhang, 2015). Henschel et al. (2013) presented hourly SO 2 profiles from roadside and urban background monitoring sites in 6 European cities, which revealed the existence of morning SO 2 peaks as a common factor to all cities, with differences in time according to the local workday dynamics. ...
... A passive sampling study made by Cuesta-Mosquera, González-Duque, Velasco-García, and Aristizábal (2018) Bimodal patterns in trace gases can be found in urban areas were traffic, industry and domestic heating are identified as SO 2 sources (Henschel et al., 2013;Hosseiniebalam & Ghaffarpasand, 2015;Syafei, Fujiwara, & Zhang, 2015). Henschel et al. (2013) presented hourly SO 2 profiles from roadside and urban background monitoring sites in 6 European cities, which revealed the existence of morning SO 2 peaks as a common factor to all cities, with differences in time according to the local workday dynamics. In Athens, for example, the morning SO 2 peak occurring around 08:00 AM (15 μg·m −3 ), was associated with vehicular A.P. Cuesta-Mosquera, et al. ...
Article
Distinct times of sulfur dioxide concentration (SO2) were observed in the main square of a tropical Andean city, revealing strong meteorological control of SO2. Concentrations were measured by UV fluorescence at 5-minute intervals, and compared to local meteorological forcing. A consistent morning peak of SO2 (4.32 μg∙m⁻³ at 7:40 AM) was concurrent with peak traffic, and occurred 10 minutes into an 80-minute period of calm (wind velocities ˂ 0.3 m s⁻1). Instead of accumulating, SO2 decreased 54%, due an expanding mixing layer. Peak evening SO2 (5.2 μg∙m⁻³ at 8:15 PM) was observed 2:15 hours after flow reversal, and consistent with travel-times of an air parcel descending from industrial facilities. The consistent anthropogenic emissions formed a pattern of daily SO2 concentration that aided in identifying more random volcanic SO2. Manizales (pop. 400000) is located on the western slope of the Cordillera Central in proximity to the Nevado del Ruiz volcano. The complex trajectory necessary for volcanic SO2 to arrive in the main square was simulated for the highest observed concentration (114 μg•m⁻³), using Hysplit and Aura-OMI information. This type of analysis can be applied to urban planning - from locating industrial zones to managing transportation - particularly in tropical montane cities.
... Furthermore, according to a climatological analysis [69] for the central, most polluted urban stations in Athens over the period of 1987-1997, a decrease of 52% in the SO 2 levels at the Patission traffic station (located at one of the most congested streets of Attica) was reported between 1988-1990 and 1995-1997 (83 ± 4 µg m −3 and 40 ± 4 µg m −3 , respectively) and is attributed to the application of abatement measures over the period of 1991-1994. The mean annual roadside levels of SO 2 further decreased to about 14 µg m −3 in 2009 [70] and 8 µg m −3 in 2019 [71]. These additional reductions in SO 2 levels can be attributed to the deindustrialization in the GAA and, on a national level, to the application of abatement measures and the reduction in emissions due to the recession after 2008 [72]. ...
... Given that biomass burning prevails in the GAA during the winter, a pH > 2 is expected during the cold period that could approach or surpass the estimations of 2.77 [95]. Such pH changes can significantly impact the partition of the nitrate ion and explain the observed summer/winter difference as well as the diurnal variation [70]. Similarly, pH changes can also explain HCl behavior, although the characterization of the effect should be more complicated as HCl formation depends not only on the levels of HNO 3 available in the gaseous phase but also on the amount of chloride from sea salt, which in turn depends on wind circulation. ...
Article
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High-resolution measurements of sulfur dioxide (SO2), nitric acid (HNO3), and hydrochloric acid (HCl) were conducted in Athens, Greece, from 2014 to 2016 via a wet rotating annular denuder system paired with an ion chromatograph. Decreased mean annual levels of SO2 and HNO3 (equal to 3.3 ± 4.8 μg m−3 and 0.7 ± 0.6 μg m−3, respectively) were observed relative to the past, whereas for HCl (mean of 0.4 μg m−3 ) no such comparison was possible as the past measurements are very scarce. Regional and local emission sources regulated the SO2 levels and contributed to both the December and the July maxima of 6.6 μg m−3 and 5.5 μg m−3, respectively. Similarly, the significant enhancement at noon and during the winter nighttime was due to transported SO2 and residential heating, respectively. The oxidation of NO2 by OH radicals and the heterogeneous reactions of HNO3 on sea salt seemed to drive the HNO3 and HCl formation, respectively, whereas nighttime biomass burning affected only the former by almost 50%. During summer, the sulfate anions dominated over the SO2, in contrast to the chloride and nitrate ions that prevailed during the winter and were linked to the aerosol acidity that influences their lifetime as well as their impact on ecosystems.
... To our knowledge studies that have used similar approaches prior to our evaluation focused on a single location within one country (Carslaw, 2005;Anttila et al., 2011) or on country-based or Europe-based results or assessed different aspects with respect to NO x , NO and NO 2 concentrations (Grice et al., 2009). The comparison between different EU cities with different air pollution sources, climatic and geographic conditions, as in this paper, may further enable the understanding of regional as well as city-specific differences (Henschel et al., 2013). ...
... The assumption was made that the monitoring sites were representative of the cityspecific patterns and trends in NO x , NO and NO 2 concentrations for that city at those sites. The stations were selected as detailed in Henschel et al. (2013). If more than 25% of hourly measurements for one of the pollutants for a given year was missing at a station, that specific year was excluded from the analysis of hourly data; no imputation was used for missing data. ...
... padimos et al. (2012) have also shown that PM 10 concentrations decreased at a number of urban background (UB) and rural background stations in five European countries. Henschel et al. (2013) reported the dramatic decrease in SO 2 levels in six European cities, which reflected the reduction in sulfur content in fuels, as part of European legislation, coupled with the shift towards the use of cleaner fuels. EEA (2013) also reported general decreases in NO 2 concentrations, even if they were lower compared to PM. ...
Article
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In this work for the first time data from two twin stations (Barcelona, urban background, and Montseny, regional background), located in the northeast (NE) of Spain, were used to study the trends of the concentrations of different chemical species in PM10 and PM2.5 along with the trends of the PM10 source contributions from the positive matrix factorization (PMF) model. Eleven years of chemical data (2004-2014) were used for this study. Trends of both species concentrations and source contributions were studied using the Mann-Kendall test for linear trends and a new approach based on multi-exponential fit of the data. Despite the fact that different PM fractions (PM2.5, PM10) showed linear decreasing trends at both stations, the contributions of specific sources of pollutants and of their chemical tracers showed exponential decreasing trends. The different types of trends observed reflected the different effectiveness and/or time of implementation of the measures taken to reduce the concentrations of atmospheric pollutants. Moreover, the trends of the contributions of specific sources such as those related with industrial activities and with primary energy consumption mirrored the effect of the financial crisis in Spain from 2008. The sources that showed statistically significant downward trends at both Barcelona (BCN) and Montseny (MSY) during 2004-2014 were secondary sulfate, secondary nitrate, and V-Ni-bearing source. The contributions from these sources decreased exponentially during the considered period, indicating that the observed reductions were not gradual and consistent over time. Conversely, the trends were less steep at the end of the period compared to the beginning, thus likely indicating the attainment of a lower limit. Moreover, statistically significant decreasing trends were observed for the contributions to PM from the industrial/traffic source at MSY (mixed metallurgy and road traffic) and from the industrial (metallurgy mainly) source at BCN. These sources were clearly linked with anthropogenic activities, and the observed decreasing trends confirmed the effectiveness of pollution control measures implemented at European or regional/local levels. Conversely, at regional level, the contributions from sources mostly linked with natural processes, such as aged marine and aged organics, did not show statistically significant trends. The trends observed for the PM10 source contributions reflected the trends observed for the chemical tracers of these pollutant sources well.
... SO 2 concentration in Milan are similar to other European cities (see Henschel et al., 2013, for an European overview) and its diurnal pattern, along with that of sulphate, shows no distinctive features, besides slightly lower concentrations on Sundays. Few stationary sources of SO 2 have significant emissions and are sufficiently near Milan to directly impact the city: the largest is an industrial area including a refinery and a carbon black manufacture sited 40 km West of the sampling site and emitting altogether ∼ 6900 Mg year −1 of SO 2 (E1 in Fig. 4). ...
Article
Full-text available
A comprehensive range of gas and particle phase pollutants were sampled at 1-hour time resolution in urban background Milan during summer 2012. Measurements include several soluble inorganic aerosols ( ) and gases (HCl, HNO2,HNO3, NH3, NO, NO2,O3, SO2), organic, elemental and black carbon and meteorological parameters. Analysis methods used include mean diurnal pattern on weekdays and Sundays, pollution roses, bivariate polar plots and statistical models using backtrajectories. Results show how nitrous acid (HONO) was mainly formed heterogeneously at nighttime, with a dependence of its formation rate on NO2 consistent with observations during the last HONO campaign in Milan in summer 1998, although since 1998 a drop in HONO levels occurred following to the decrease of its precursors. Nitrate showed two main formation mechanisms: one occurring through N2O5 at nighttime and leading to nitrate formation onto existing particles; another occurring both daytime and nighttime following the homogeneous reaction of ammonia gas with nitric acid gas. Air masses reaching Milan influenced nitrate formation depending on their content in ammonia and the timing of arrival. Notwithstanding the low level of SO2 in Milan, its peaks were associated to point source emissions in the Po valley or shipping and power plant emissions SW of Milan, beyond the Apennines. A distinctive pattern for HCl was observed, featured by an afternoon peak and a morning minimum, and best correlated to atmospheric temperature, although it was not possible to identify any specific source. The ratio of primary-dominated organic carbon and elemental carbon on hourly PM2.5 resulted 1.7. Black carbon was highly correlated to elemental carbon and the average mass absorption coefficient resulted MAC = 13.8 ± 0.2 m² g −1. It is noteworthy how air quality for a large metropolitan area, in a confined valley and under enduring atmospheric stability, is nonetheless influenced by sources within and outside the valley.
... In A Coruña, shipping and the proximity of coal-fired power stations are important contributors to SO 2 levels. The lowest levels were observed in Barcelona (1.0 lg m À3 in winter and 1.5 lg m À3 in summer), where shipping has been identified as the main source of SO 2 (Henschel et al., 2013). ...
Article
A detailed spatial and temporal assessment of urban NH3 levels and potential emission sources was made with passive samplers in six major Spanish cities (Barcelona, Madrid, A Coruña, Huelva, Santa Cruz de Tenerife and Valencia). Measurements were conducted during two different periods (winter-autumn and spring-summer) in each city. Barcelona showed the clearest spatial pattern, with the highest concentrations in the old city centre, an area characterised by a high population density and a dense urban architecture. The variability in NH3 concentrations did not follow a common seasonal pattern across the different cities. The relationship of urban NH3 with SO2 and NOX allowed concluding on the causes responsible for the variations in NH3 levels between measurement periods observed in Barcelona, Huelva and Madrid. However, the factors governing the variations in A Coruña, Valencia and Santa Cruz de Tenerife are still not fully understood. This study identified a broad variability in NH3 concentrations at the city-scale, and it confirms that NH3 sources in Spanish urban environments are vehicular traffic, biological sources (e.g. garbage containers), wastewater treatment plants, solid waste treatment plants and industry. The importance of NH3 monitoring in urban environments relies on its role as a precursor of secondary inorganic species and therefore PMX. Further research should be addressed in order to establish criteria to develop and implement mitigation strategies for cities, and to include urban NH3 sources in the emission inventories.
... Earlier studies indicate that sulfate accounts for over Asia and parts of Africa, the levels are higher than 4 ppbv. The European cities show a decrease in SO 2 levels of the order of 4-10% per year ( Henschel et al., 2013). Decrease in SO 2 leves is observed in some parts of Asia e.g. a 16% concentration reduction in Seoul (Korea) between 1987(Khan et al., 2017. ...
Article
In a scenario when haze and smog events are wreaking havoc in many parts of the world, accurate information on ambient sulfur dioxide (SO 2 ) sources is a required input to models for prediction and mitigation of air pollution. Globally, India is one of the highest emitters of anthropogenic SO 2 . However, the Ozone Monitoring Instrument (OMI) data reveal that unlike many other anthropogenic air pollutants, the strongest anthropogenic SO 2 sources are not located in the Indo-Gangetic plain (IGP) but over the coal belts of North Eastern peninsular India. In this study, we report SO 2 measurements conducted at Bhubaneswar, a rapidly developing smart city in the Eastern Coast of India. The city is ideally located just downwind of the Indian SO 2 hotspots during winter, when SO 2 concentrations are the highest, reaching 14.3 ppbv for hourly averaged data. The measurements, reported here from the summer of 2010 to the summer of 2012, show that despite being a rapidly developing location, SO 2 over Bhubaneswar is dominated by regional emissions rather than local sources like vehicular exhausts. The influence of regional emissions is strongest in winter as the city is directly downwind of 6 of the 10 largest thermal power plants and 7 out of the 13 largest integrated steel plants in India with a mean SO 2 concentration of 3.2 ppbv. This is evinced by multiple pointers viz. Concentration-Weighted Trajectory (CWT) analysis for surface SO 2 data, correlation analysis for OMI SO 2 data, analysis of surface concentrations of SO 2 , organic carbon, black carbon and carbon monoxide; which reveal SO 2 emissions from the industrial and mining regions of Chhattisgarh and north-west Odisha. This is the same region that shows up as hotspots of SO 2 in OMI retrievals over India. However, despite being downwind of major SO 2 sources during winter, SO 2 concentrations in Bhubaneswar are lower than over some other cities (Kolkata, Kanpur) in the IGP, due to influence of strong local sources in the later cases. Unlike most other urban regions in India, the diurnal variation of SO 2 over Bhubaneswar shows elevated daytime values due to predominant influence of regional emissions.
... Indeed particulates, CO and the other emissions have been established to impact adversely on human health, mortality and related effects besides generally worsening air quality in a particular area (e.g. Henschel et al., 2013;Caiazzo et al., 2013). ...
Article
This paper contributes to the environmental Kuznets curve (EKC) literature, which posits an inverted U-shaped relationship between pollution and income, but from a spatial perspective. We explore several spatial statistical and econometric analyses to account for spatial dependence in emissions from carbon dioxide, sulfur dioxide, nitrogen oxides, carbon monoxide, particulate matter (2.5 and 10) and total suspended particulates between all 290 Swedish municipalities. Our results suggest the EKC significantly holds for all but one pollutant (i.e. carbon monoxide) and that this relationship is significantly characterized by spatial dependence. Specifically, we find significant neighbourhood effects as well as significant positive economic spillovers at low income which turns negative at high income on both within and inter-municipality air emissions. Our results and hence implications suggest transboundary pollution control policies aimed at abatement would be more effective through enhanced coordination between adjacent municipalities.
... The double-peak pattern of SO2 over roadside sites indicates that SO2 is influenced by emission primarily from vehicle exhaust using high sulfur content fuel, especially high sulfur diesel. The study of ambient air SO2 patterns 15 in European cities by Henschel et al. (2013) showed that diurnal patterns of SO2 had a double-peak pattern which the morning peaks more likely related to emission during rush hour, evening peaks were possibly caused by traffic and meteorology-collapse of the planetary boundary layer. It is noteworthy that BKK has a large diesel engine fleet (an estimated 25 % of registered vehicles) (DLT, 2015a). ...
Article
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Analysis of gaseous criteria pollutants in Bangkok Metropolitan Region (BMR), Thailand, during 2010–2014 reveals that the hourly concentrations of CO, SO2 and NO2 were mostly below the National Ambient Air Quality Standards (NAAQs) of Thailand. However, the hourly concentrations of O3 exceeded the Thailand NAAQs. The maximum concentrations of O3 ranged from 120–190 ppb. On average, the number of hourly O3 exceedances ranged from 1–60 hours a year depending on monitoring station locations. The exceedances occurred during the summer and winter, dry seasons. Interconversion between O3, NO and NO2 indicates crossover points between species occur when the concentration of NOx ([NOx] = [NO]+[NO2]) is ~ 60 ppb. However, when [NOx] 3 is the dominant species; conversely, NO dominates when [NOx] > 60 ppb. The calculated photochemical reaction rate (the reaction between NO2 with sunlight), during photostationary state ranges from 0.12 to 1.22 min−1. Linear regression analysis between the concentrations of Ox ([Ox ] = [O3]+[NO2]) and NOx provides the role of local and regional contributions to Ox . Both the local and regional Ox contributions enhance the concentration of Ox . Values of the local and regional Ox contributions during non-episode were ~ 44–54 ppb and ~ 0.13[NOx ] to 0.33[NOx ], respectively. Those values were about double during O3 episodes ([O3] > 100 ppb). Ratio analysis suggests that the major contributors of primary pollutants over BMR are mobile sources (CO/NOx = 19.8). The Air Quality Index (AQI) for BMR was predominantly between good to moderate. Unhealthy O3 categories were observed during episode conditions in the region.
... The analysis could be used in the future to assess the effectiveness of any implemented emission control strategies. Henschel et al. (2013) analyzed hourly inter-annual, seasonal, and weekday-specific SO 2 concentration patterns using data obtained from six European cities. The results show that an analysis of hourly pollution patterns can be useful in understanding city-specific activity patterns, such as rush-hour traffic and evening space heating. ...
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There is a great demand for estimating the ambient air pollutant background concentrations in order to assess the effectiveness of different emission control strategies. In this paper, the background concentrations of four pollutants, namely sulfur dioxide (SO2), nitrogen oxides (NOx), carbon monoxide (CO), and ozone (O3) pollutants in urban, suburban, and rural environments were investigated using Kolmogorov–Zurbenko (KZ) filter technique. Air quality data from monitoring stations over a period of 4 years (2007–2010) was analyzed for three locations in Kuwait, namely urban, suburban, and rural. The spatial and temporal (daily, weekly, and monthly) variations of the four pollutants were analyzed. The results show that the levels of ambient air pollutant background concentrations were high in the urban site compared to suburban and rural area. The diurnal variation of SO2 concentration showed an early morning peak, while the diurnal variation of NOx concentration constituted has two peaks, one was in the early morning hours (5 to 8 a.m.) and the second was in nighttime hours (8 to 11 p.m.). These two peaks were observed at all three locations. The monthly background NOx concentration reached a maximum in winter and minimum in summer. Diurnal variation of CO concentration showed a similar trend to SO2 concentrations in all three locations. Because of the photochemical reactions that occur in the atmosphere, the background concentration of O3 showed an inverse relation with respect to background concentration of NOx.
... Although 16 similar studies on the WD/WN effect were published from 1995 to 2014 [15][16][17][18][19][20][21]35,36,[40][41][42][43][44][45], our current work has identified a strong relationship (and interdependence) between the NO, NO 2 , O 3 and CO WD/WN and WD/Sun effect and the meteorological parameters. Of the aforementioned 16 references, it was noted that the concentrations of specific air pollutants (i.e., SO 2 , NO x and PM 10 ) are nearly constant on weekdays (WD) but were approximately 40-60% lower on weekends (WN) in southwestern Germany [46]. ...
Article
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We present evidence on the short-term differences in airborne pollution levels in terms of weekday/weekend (WD/WN) and weekday/Sunday (WD/Sun) intervals. To this end, we analyzed the hourly data of important pollutants (nitric oxide (NO), nitrogen dioxide (NO2), ozone (O3) and carbon monoxide (CO)) using the data acquired in the Yong-San district of Seoul, Korea from 2009 to 2013. For each week, the pollutant ratio (Rw) was estimated through either WD/WN or WD/Sun. Here, a week is defined as Sunday through Saturday, WD as Monday through Friday and WN as Sunday and Saturday. The WD/Sun Rw geometric means (and range) were 2.02 (0.27-15.5) for NO, 1.29 (0.49-5.7) for NO2 and 0.89 (0.17-7.2) for O3 while the fraction of Rw (WD/Sun) > 1 were 81, 71 and 38%, respectively. NO and CO levels were much higher in October through March (during Autumn and Winter) than April through September (during Spring and Summer), reflecting the potential effect of fuel consumption (e.g., in terms of use patterns of nationwide city natural gas). Thus, we provide a broader interpretation on the occurrence patterns of the major pollutants (e.g., NO, NO2, O3 and CO) in relation to temporal changes in man-made activities.
... Discharge from industrial activities, emissions from traffic-related gas and the conversion between primary and secondary PM 2.5 pollution are the dominant sources of NO x (Reyes and Serre, 2014;Notario et al., 2012), which have been detected in many cities. In addition to background S that is naturally present in the air, industrial activities and automobiles also contribute SO 2 to the atmosphere (Henschel et al., 2013). Heavy metal particles are the predominant PM 2.5 pollutants, and inorganic acids (SO 4 2− , NO 3 − , NH 4 + ) are key secondary PM 2.5 pollutants (Perrone et al., 2012). ...
... Conversely, in Europe, the strong decreasing trend observed for SO 2 (e.g. Tørseth et al., 2012;Henschel et al., 2013) and, with a lower spatial homogeneity and statistical significance, for PM 2.5 (e.g. EEA, 2016) is not observed for aerosol optical properties. ...
Article
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This paper presents the light-scattering properties of atmospheric aerosol particles measured over the past decade at 28 ACTRIS observatories, which are located mainly in Europe. The data include particle light scattering (σsp) and hemispheric backscattering (σbsp) coefficients, scattering Ångström exponent (SAE), backscatter fraction (BF) and asymmetry parameter (g). An increasing gradient of σsp is observed when moving from remote environments (arctic/mountain) to regional and to urban environments. At a regional level in Europe, σsp also increases when moving from Nordic and Baltic countries and from western Europe to central/eastern Europe, whereas no clear spatial gradient is observed for other station environments. The SAE does not show a clear gradient as a function of the placement of the station. However, a west-to-east-increasing gradient is observed for both regional and mountain placements, suggesting a lower fraction of fine-mode particle in western/south-western Europe compared to central and eastern Europe, where the fine-mode particles dominate the scattering. The g does not show any clear gradient by station placement or geographical location reflecting the complex relationship of this parameter with the physical properties of the aerosol particles. Both the station placement and the geographical location are important factors affecting the intra-annual variability. At mountain sites, higher σsp and SAE values are measured in the summer due to the enhanced boundary layer influence and/or new particle-formation episodes. Conversely, the lower horizontal and vertical dispersion during winter leads to higher σsp values at all low-altitude sites in central and eastern Europe compared to summer. These sites also show SAE maxima in the summer (with corresponding g minima). At all sites, both SAE and g show a strong variation with aerosol particle loading. The lowest values of g are always observed together with low σsp values, indicating a larger contribution from particles in the smaller accumulation mode. During periods of high σsp values, the variation of g is less pronounced, whereas the SAE increases or decreases, suggesting changes mostly in the coarse aerosol particle mode rather than in the fine mode. Statistically significant decreasing trends of σsp are observed at 5 out of the 13 stations included in the trend analyses. The total reductions of σsp are consistent with those reported for PM2.5 and PM10 mass concentrations over similar periods across Europe.
... As result of the implemented abatement policies, emissions of large number of air pollutants decreased in the last decades across Europe (e.g., Harrison et al., 2008;EEA, 2016), resulting in generally improved air quality across the EU. Nowadays, most European zones meet the air quality limits established for CO, SO 2 , and metals (e.g., Querol et al., 2014;Henschel et al., 2013;EEA, 2016). However, emissions of nitrogen oxides (NO x , NO x = NO + NO 2 ) from road transport have not decreased sufficiently, and NO 2 ambient concentration, especially at roadside sites, has not decreased as expected, and even in some cases NO 2 concentration has increased (EEA, 2016). ...
Article
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A large part of the European population is still exposed to ambient nitrogen dioxide (NO2) levels exceeding the European Union (EU) air quality standards, being a key challenge to reduce NO2 concentrations across many European urban areas, particularly close to roads. In this work, a trend analysis of pollutants involved in NO2 processes was done for the period 2003-2014 in traffic sites from three Spanish cities (Barcelona, Madrid and Granada) that still exceed the European NO2 air quality standard limits. We also estimated the contributions of primary NO2 emissions and photo-chemically formed NO2 to the observed ambient NO2 concentrations in order to explore their possible role in the observed NO2 concentration trends. The NOx and NO concentrations at these traffic sites showed significant decreasing trends during the period 2003-2014, especially at Barcelona (BARTR) and Madrid (MADTR) traffic stations. The NO2 concentrations showed statistically significant downward trends at BARTR and MADTR and remained unchanged at Granada traffic station (GRATR) during the study period. Despite the significant decrease in NO2 concentrations in BCNTR and MADTR during the analysed period, the NO2 concentrations observed over these sites still above the annual NO2 standard limit of 40 µg m-3 and, therefore, more efficient measures are still needed. Primary NO2 emissions significantly influence NO2 concentrations at the three analysed sites. However, as no drastic changes are expected in the after-exhaust treatment technology that can reduce primary NO2 emissions to zero in the near future, only a substantial reduction in NOx emissions will help to comply with the NO2 European air quality standards. Reduction of 78%, 56% and 16% on NOx emissions in Barcelona, Madrid and Granada were estimated to be necessary to comply with the NO2 annual limit of 40 µg m-3.
... Within the context of the many changing factors that determine temporal patterns in SO 2 levels, Henschel et al. (2013) failed, on a subset of city, to identify clear step changes in measured concentrations, either by using graphical techniques or statistical techniques designed to identify changes in mean values over time (CUSUM). The latter technique has been used successfully in the context of assessing changes in air pollution trends (Barratt et al. 2007). ...
Article
Following the implementation of three successive European Directives during the 1990s to reduce the sulphur content of fuels, background SO2 concentrations in European cities have fallen substantially. We investigated the magnitude of the short-term associations between daily SO2 concentrations and mortality during the various phases of legislation. Daily counts of all-cause and cause-specific mortality, SO2 concentration, temperature and humidity were obtained for 20 European cities participating in the Aphekom project during 1990–2008. Poisson regression was used to estimate the city-specific risks of death associated with changes in SO2 concentrations for the time periods before legislation and subsequent periods following the implementation of the three European Directives. City-specific risk estimates were pooled using meta-regression. We also estimated the health impact associated with changes in SO2 concentrations during these pre-and post-implementation periods. During the study period, 10 μg/m3 increases in SO2 levels were associated with increases in all-cause (0.53 %), respiratory (0.49 %) and cardiovascular (0.72 %) mortality. We found no evidence of changes in the SO2 concentration–response function across the implementation periods. We estimated, annually, a total of 639, 1,093 and 1,616 premature deaths across the 14 EU cities as result of respective reductions in SO2 concentrations in each of the three implementation periods. Our study suggests that the linear relationship between daily SO2 concentrations and mortality has remained unaltered despite substantial reductions in ambient concentrations in recent years arising from EU directives to limit sulphur content in fuel. This linearity suggests that new legislation to reduce SO2 concentrations further will bring about additional public health benefits.
... Regarding the diurnal cycle of SO 2 for all seasons, the highest concentrations were measured in winter due to emissions by domestic heating and coal-fired power plants (Hamed et al. 2010) as well as enrichment in the inversion layer. Furthermore, for all seasons the highest concentrations occurred at noon, which is in agreement with the measurements performed by Henschel et al. (2013). The SO 2 noontime peak was investigated by Xu et al. (2014) for measurements performed in the North China Plain (NCP). ...
Article
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An hourly quantification of inorganic water-soluble PM10 ions and corresponding trace gases was performed using the Monitor for AeRosols and Gases in ambient Air (MARGA) at the TROPOS research site in Melpitz, Germany. The data availability amounts to over 80% for the five-year measurement period from 2010 to 2014. Comparisons were performed for the evaluation of the MARGA, resulting in coefficients of determinations (slopes) of 0.91 (0.90) for the measurements against the SO2 gas monitor, 0.84 (0.88), 0.79 (1.39), 0.85 (1.20) for the ACSM NO3⁻, SO4²⁻ and NH4⁺ measurements, respectively, and 0.85 (0.65), 0.88 (0.68), 0.91 (0.83), 0.86 (0.82) for the filter measurements of Cl⁻, NO3⁻, SO4²⁻ and NH4⁺, respectively. A HONO comparison with a batch denuder shows large scatter (R² = 0.41). The MARGA HNO3 is underestimated compared to a batch and coated denuder with shorter inlets (slopes of 0.16 and 0.08, respectively). Less NH3 was observed in coated denuders for high ambient concentrations. Long-time measurements show clear daily and seasonal variabilities. Potential Source Contribution Function (PSCF) analysis indicates the emission area of particulate ions Cl⁻, NO3⁻, SO4²⁻, NH4⁺, K⁺ and gaseous SO2 to lie in eastern European countries, predominantly in wintertime. Coarse mode sea salt particles are transported from the North Sea to Melpitz. The particles at Melpitz are nearly neutralised with a mean molar ratio of 0.90 for the five-year study. A slight increase of the neutralization ratio over the last three years indicates a stronger decrease of the anthropogenically emitted NO3⁻ and SO4²⁻ compared to NH4⁺.
... Adjusting by gross domestic product per capita, for instance, would lead to a fourfold lower VOLY in Budapest than in Dublin. 32 Figure 1 shows a plot of yearly UB SO 2 averages for 12 Aphekom cities from 1990 to 2004 (see Henschel et al. 33 for a detailed analysis of the hourly SO 2 pollution patterns for six of the cities). There is no clear step change in UB SO 2 concentrations after implementation of the directives; rather, a gradual decline in SO 2 levels is observed. ...
Article
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Background: Since the 1970s, legislation has led to progress in tackling several air pollutants. We quantify the annual monetary benefits resulting from reductions in mortality from the year 2000 onwards following the implementation of three European Commission regulations to reduce the sulphur content in liquid fuels for vehicles. Methods: We first compute premature deaths attributable to these implementations for 20 European cities in the Aphekom project by using a two-stage health impact assessment method. We then justify our choice to only consider mortality effects as short-term effects. We rely on European studies when selecting the central value of a life-year estimate (€ 2005 86 600) used to compute the monetary benefits for each of the cities. We also conduct an independent sensitivity analysis as well as an integrated uncertainty analysis that simultaneously accounts for uncertainties concerning epidemiology and economic valuation. Results: The implementation of these regulations is estimated to have postponed 2212 (95% confidence interval: 772-3663) deaths per year attributable to reductions in sulphur dioxide for the 20 European cities, from the year 2000 onwards. We obtained annual mortality benefits related to the implementation of the European regulation on sulphur dioxide of € 2005 191.6 million (95% confidence interval: € 2005 66.9-€ 2005 317.2). Conclusion: Our approach is conservative in restricting to mortality effects and to short-term benefits only, thus only providing the lower-bound estimate. Our findings underline the health and monetary benefits to be obtained from implementing effective European policies on air pollution and ensuring compliance with them over time.
... Ìåaeäó êîíöåíòðàöèÿìè â ñóáòðîïè÷åñêîé è òðîïè-÷åñêîé ìàññàõ äîñòîâåðíîñòü íàõîäèòñÿ íà óðîâíå 0,01. Óñèëèÿ ìèðîâîãî ñîîáùåñòâà ïî óìåíüøåíèþ àíòðîïîãåííûõ âûáðîñîâ äèîêñèäà ñåðû ïðèâåëè ê çíà÷èòåëüíîìó óìåíüøåíèþ ôîíîâîé êîíöåíòðà-öèè SO 2 âî ìíîãèõ ðåãèîíàõ çåìíîãî øàðà [49][50][51] ...
Article
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Data of multiyear monitoring at the TOR station are used to calculate the average concentrations of gas and aerosol constituents in different air masses in the region of Tomsk. It is shown that CO2 and CH4 are characterized by a decrease in concentrations in going from an Arctic to a tropical air mass. Ozone shows the opposite pattern: the largest concentrations are recorded in the tropical air mass and the smallest concentrations in the Arctic air mass. Such gases as CO and SO2 show distributions more complex in character.
... As a result of the implemented abatement policies, emissions of large number of air pollutants decreased in the last decades across Europe (e.g., EEA, 2019), resulting in generally improved air quality across the European Union (EMEP, 2016). Nowadays, most European zones meet the air quality limits established for CO, SO 2 and metals (e.g., Henschel et al., 2013;Querol et al., 2014;EEA, 2019). However, despite these policy efforts during the last decades, in 2017 around 8% and 77% of the EU-28 population was exposed to concentrations of PM 2.5 (particulate matter with diameter < 2.5 μm) exceeding the European air quality standards and the World Health Organization (WHO) Air Quality guidelines, respectively (EEA, 2019). ...
Article
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In this study, we propose a new approach to determine the contributions of primary vehicle exhaust (N1ff), primary biomass burning (N1bb) and secondary (N2) particles to mode segregated particle number concentrations. We used simultaneous measurements of aerosol size distribution in the 12-600 nm size range and black carbon (BC) concentration obtained during winter period at urban and suburban sites influenced by biomass burning (BB) emissions. As expected, larger aerosol number concentrations in the 12-25 and 25-100 nm size ranges are observed at the urban site compared to the suburban site. However, similar concentrations of BC are observed at both sites due to the larger contribution of BB particles to the observed BC at suburban (34%) in comparison to urban site (23%). Due to this influence of BB emissions in our study area, the application of the Rodríguez and Cuevas (2007) method, which was developed for areas mainly influenced by traffic emissions, leads to an overestimation of the primary vehicle exhaust particles concentrations by 18% and 26% in urban and suburban sites, respectively, as compared to our new proposed approach. The results show that (1) N2 is the main contributor in all size ranges at both sites, (2) N1ff is the main contributor to primary particles (>70%) in all size ranges at both sites and (3) N1bb contributes significantly to the primary particles in the 25-100 and 100-600 nm size ranges at the suburban (24% and 28%, respectively) and urban (13% and 20%, respectively) sites. At urban site, the N1ff contribution shows a slight increase with the increase of total particle concentration, reaching a contribution of up to 65% at high ambient aerosol concentrations. New particle formation events are an important aerosol source during summer noon hours but, on average, these events do not implicate a considerable contribution to urban particles.
... SO 2 concentrations were highest for winds blowing from 100 to 180°(especially 160-180°) that is the location of the harbour. Barcelona is registering very low SO 2 levels compared other European cities (Henschel et al., 2013), especially since 2008 when power generation was restricted to only natural gas in the metropolitan area. Thus, currently the main source of SO 2 in the city is shipping. ...
Article
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Ultrafine particles (UFP) are suspected of having significant impacts on health. However, there have only been a limited number of studies on sources of UFP compared to larger particles. In this work, we identified and quantified the sources and processes contributing to particle number size distributions (PNSD) using Positive Matrix Factorization (PMF) at six monitoring stations (four urban background and two street canyon) from four European cities: Barcelona, Helsinki, London, and Zurich. These cities are characterised by different meteorological conditions and emissions. The common sources across all stations were Photonucleation, traffic emissions (3 sources, from fresh to aged emissions: Traffic nucleation, Fresh traffic - mode diameter between 13 and 37 nm, and Urban - mode diameter between 44 and 81 nm, mainly traffic but influenced by other sources in some cities), and Secondary particles. The Photonucleation factor was only directly identified by PMF for Barcelona, while an additional split of the Nucleation factor (into Photonucleation and Traffic nucleation) by using NOx concentrations as a proxy for traffic emissions was performed for all other stations. The sum of all traffic sources resulted in a maximum relative contributions ranging from 71 to 94% (annual average) thereby being the main contributor at all stations. In London and Zurich, the relative contribution of the sources did not vary significantly between seasons. In contrast, the high levels of solar radiation in Barcelona led to an important contribution of Photonucleation particles (ranging from 14% during the winter period to 35% during summer). Biogenic emissions were a source identified only in Helsinki (both in the urban background and street canyon stations), that contributed importantly during summer (23% in urban background). Airport emissions contributed to Nucleation particles at urban background sites, as the highest concentrations of this source took place when the wind was blowing from the airport direction in all cities.
... The p5 values (1.1-1.2 μg m −3 ) were similar throughout the seasons and similar to the minimum seasonal reported levels and close to the detection limit of the instrument. These values were typical of background environments free of SO 2 emission impact (Luvsan et al., 2012), lower than values measured in several European cities (Henschel et al., 2013) and higher than values observed during one-year in Cape Granitola (Italy) (Cristofanelli et al., 2017). However, in stations under the influence of urban or industrial plumes, SO 2 concentrations can reach mean levels of 20-30 μg m −3 (Adame et al., 2012;Borge et al., 2018), with hourly levels up to 300 μg m −3 for SO 2 emissions coming mainly from industrial activities and also associated with different meteorological conditions, such as strong vertical mixing processes in the late morning hours (Adame et al., 2012). ...
Article
Two years of SO2 measurements at El Arenosillo observatory located in the Gulf of Cadiz (Atlantic Ocean) were investigated. Annual hourly averages of 1.9 ± 1.5 μg m-3 and p95 between 3 and 4.4 μg m-3 were recorded, showing clean and background environments. Monthly means vary between 1.5 and 2.4 μg m-3, a monthly evolution was not found. SO2 fields from the MERRA2 model were used to identify SO2 sources and its transport, which could be affecting the studied region. Although SO2 records were low, major conductive for SO2 increases were observed in specific periods. A selection methodology was applied to extract these events, which showed a mean of ~11 μg m-3. Surface meteorological observations and ERA5 meteorological fields from the ECMWF model were used to assess the weather conditions. SO2 increases, in cold months occurred under conditions governed by synoptic-scale. Two types of transport scenarios were identified: SO2 transport defined as direct impact, which is the sum of the plumes from Portugal and the Huelva area; and indirect impact, where SO2 and sulphate particle emissions from Portugal were transported and accumulated in the Gulf of Cadiz and then carried inland, where new particle formation were observed. Episodes with high SO2 concentrations were also reported in warm periods associated with pure sea-land breezes. The SO2 peaks under sea-land breezes were associated with the transport of SO2 from the south of Portugal to the Gulf of Cadiz, whereas SO2 from the east of the Iberian Peninsula and north of Africa reached the Mediterranean Sea and were then transported to the Atlantic Ocean following the Strait of Gibraltar. Blocking of the airflows from the Mediterranean Sea to the Atlantic Ocean turns the Gulf of Cadiz into a chemical reservoir, where chemical species such as SO2 can accumulate, triggering new particle formation processes.
... Therefore, analyzing the long-term variations in weather change that occur at a particular location is very useful for understanding the concentration of surface O3 concentrations [33][34][35][36][37][38]. Many studies [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] on the variations of O3 and its precursor gases revealed that higher surface O3 concentrations were observed in summer/autumn seasons and lower concentrations were observed during monsoon season. ...
Article
Full-text available
Atmospheric ozone (O3) in the surface level plays a central role in determining air quality and atmospheric oxidizing capacity. In this paper, we review our comprehensive results of simultaneous measurements of surface ozone (O3) and its precursor gas (NOx) and weather parameters that were carried out continuously for a span of six years (January 2013–December 2018) at a typical rural coastal site, Kannur (11.9ON, 75.4OE) in South India. Surface O3 concentration reached its maximum during daytime hours and minimum during the night time. The influence of solar radiation and water content on variations of O3 are discussed. A Multi-Layer Perceptron (MLP) artificial neural network technique has been used to understand the effect of atmospheric temperature on the increase in O3 over the past six years. This has been found that temperature has been a major contributor to the increase in O3 levels over the years. The National Centre for Atmospheric Research- Master Mechanism (NCAR-MM) Photochemical box model study was conducted to validate the variations of O3 in different seasons and years, and the results were shown to be in good agreement with observed trends.
... SO 2 measurements were also available; however, they were excluded from our analysis due to significant gaps in the data series. However, the SO 2 levels have been significantly reduced in Athens during the last decades (Henschel et al. 2013;Dimitroulopoulou and Ziomas 2012), and thus, its exclusion from the analysis is expected to have a minor effect on the overall estimation of air quality. To assure the reliability of the AQI results, only days with at least 18 available hourly values of all four pollutants were used, resulting to 956 valid days. ...
Article
Full-text available
To evaluate air quality in Athens (Greece), hourly concentrations of PM10, NO2, O3, and CO from an urban background monitoring station and a suburban sampling site, covering the years 2014–2018, were used for the calculation of individual daily air quality indices (AQIs), reflecting the impact of each pollutant on air quality. Individual AQIs were then integrated in a previously reported formula for the computation of a daily aggregate AQI (AQIagg) expressing the overall air stress. According to the results of AQIagg, a generally moderate air quality was estimated in Athens; however, an increased likelihood of extreme AQIagg episodes was calculated during the warm period (16 April–15 October), due to the combination of enhanced PM10 and O3 concentrations. Approximately 83% of AQIagg episodes occurred during the warm period and only 17% in cold period (16 October–15 April). Peaks of AQIagg in cold period were primarily related to desert dust intrusions from North Africa. AQIPM10 and AQIO3 were the primary contributors to AQIagg, whereas AQINO2 and AQICO remained at low levels. AQIPM10 and AQIO3 had the highest contribution to AQIagg on 72% and 28% of total days respectively. Atmospheric circulation patterns produced by a K-means cluster analysis procedure revealed that extended low pressure areas centered over the UK were associated with dust importation in Athens due to the triggering of southwestern airflows by the cyclonic activity. Strong correlations between the individual and aggregate AQIs calculated at the urban background and the suburban sampling site were found, indicating relatively uniform air quality conditions inside the Athens basin. Mean annual AQIagg values at the suburban station for the years 2001–2018 showed a gradual amelioration and stabilization of air quality in Athens after 2008, related to the status of Greek economy and depollution measures.
... Aphekom was developed to improve knowledge and communication for decision-making on air pollution and health in Europe [57]. This tool has been widely used in several long-run studies in European cities and provided seminal findings that served as the baseline in the design of environmental policies aiming to ameliorate the effects of PM 2.5 pollution [58][59][60][61][62][63]. Aphekom tool simulates outputs on how the number of deaths per 100,000 inhabitants would decrease if PM 2.5 declined under specific predetermined values. ...
Article
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Introduction: This study provides an economic assessment of the health effects due to exposure to particulate matter PM2.5 in three medium-size cities of northwestern Mexico: Los Mochis, Culiacan and Mazatlán. People in these cities are exposed to high pollutant concentrations that exceed limits suggested in domestic and international guidelines. PM2.5 is an air contaminant negatively associated with people’s health when is highly concentrated in the atmosphere; its diameter is below 2.5 µm and causes the air to appear hazy when levels are elevated. To account for the economic impact of air pollution, a Health Impact Assessment (HIA) was used by the means of the European Aphekom Project. We figured the cost-savings of complying with current environmental standards and computed gains in life expectancy, total avoidable premature mortality, preventable cardiovascular disease, and the economic costs of air pollution related to PM2.5. A formal analysis of air pollution epidemiology is not pursued in this paper. Results: The cost of reducing PM2.5 pollution associated with negative health outcomes was based on two different scenarios: Official Mexican Standard (NOM, Spanish acronym) and World Health Organization (WHO) environmental standards. The mean PM2.5 concentrations in 2017 were 22.8, 22.4 and 14.1 µg/m3 for Los Mochis, Mazatlán and Culiacan, respectively. Conclusions: The mean avoidable mortality for all causes associated to PM2.5 exposure in these cities was 638 for the NOM scenario (i.e., with a reduction to 12 µg/m3) compared to 739 for the WHO scenario (reduction to 10 µg/m3). Complying with the WHO guideline of 10 µg/m3 in annual PM2.5 mean would add up to 15 months of life expectancy at age 30, depending on the city. The mean economic cost per year of the PM2.5 effects on human life in these three cities was USD 600 million (NOM scenario) and USD 695 million (WHO scenario). Thus, effective public health and industrial policy interventions to improve air quality are socially advantageous and cost-saving to promote better health.
... Therefore, analyzing the long-term variations in weather change that occur at a particular location is very useful for understanding the concentration of surface O3 concentrations [33][34][35][36][37][38]. Many studies [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] on the variations of O3 and its precursor gases revealed that higher surface O3 concentrations were observed in summer/autumn seasons and lower concentrations were observed during monsoon season. ...
Article
Full-text available
Atmospheric ozone (O3) in the surface level plays a central role in determining air quality and atmospheric oxidizing capacity. In this paper, we review our comprehensive results of simultaneous measurements of surface ozone (O3) and its precursor gas (NOx) and weather parameters that were carried out continuously for a span of six years (January 2013-December 2018) at a typical rural coastal site, Kannur (11.9 O N, 75.4 O E) in South India. Surface O3 concentration reached its maximum during daytime hours and minimum during the night time. The influence of solar radiation and water content on variations of O3 are discussed. A Multi-Layer Perceptron (MLP) artificial neural network technique has been used to understand the effect of atmospheric temperature on the increase in O3 over the past six years. This has been found that temperature has been a major contributor to the increase in O3 levels over the years. The National Centre for Atmospheric Research-Master Mechanism (NCAR-MM) Photochemical box model study was conducted to validate the variations of O3 in different seasons and years, and the results were shown to be in good agreement with observed trends.
... Sulfuric acid is elevated during both full-event and burst-event periods. In urban Barcelona, sulfuric acid will primarily arise from oxidation of SO 2 by the OH q radical, with anthropogenic emissions such as shipping emissions from the port areas being significant sources of SO 2 (Henschel et al., 2013). Direct traffic emissions have been shown to be a significant primary sulfuric acid source (Olin et al., 2020), but our sulfuric acid data show no traffic peaks. ...
Article
Full-text available
Atmospheric aerosols contribute some of the greatest uncertainties to estimates of global radiative forcing, and have significant effects on human health. New particle formation (NPF) is the process by which new aerosols of sub-2 nm diameter form from gas-phase precursors and contributes significantly to particle numbers in the atmosphere, accounting for approximately 50 % of cloud condensation nuclei globally. Here, we study summertime NPF in urban Barcelona in NE Spain. The rate of formation of new particles is seen to increase linearly with sulphuric acid concentration in a manner similar to systems studied in chamber studies involving sulphuric acid, water and dimethylamine (DMA), as well as sulphuric acid, water and the oxidation products of pinanediol. The sulphuric acid dimer : monomer ratio is significantly lower than that seen in experiments involving sulphuric acid and DMA in chambers, indicating that stabilization of sulphuric acid clusters by bases is weaker in this dataset than in chambers, and thus another mechanism, likely involving the plentiful highly oxygenated organic molecules (HOMs) is plausible. The high concentrations of HOMs arise largely from both alkylbenzene and monoterpene oxidation, with the former providing greater concentrations of HOMs due to significant local sources. The concentration of these HOMs shows a dependence on both temperature and precursor VOC concentration. New particle formation without growth past 10 nm is also observed, and on these days the highly oxygenated organic compound concentration is significantly lower than on days with growth, and thus high concentrations of low volatility oxygenated organics appear to be a necessary condition for the growth of newly formed particles in Barcelona. These results are consistent with prior observations of new particle formation in both chambers and the real atmosphere, and these results are likely representative of the urban background of many European Mediterranean cities.
... In this paper, air quality data recorded in these different European cities was analyzed for a 10-year period (where available), focusing on the main critical pollutants in urban areas, combining different approaches (Flemming et al., 2005;Gama et al., 2018;Henschel et al., 2013;Jo & Park, 2005;Liu et al., 2015;Lonati et al., 2006;Zhao et al., 2009). The paper is organised as follows: in Section 2, the air quality data collection methodology along the six cities is described in detail, followed by a description of the six urban case studies main characteristics. ...
Article
European cities have made significant progress over the last decades towards clean air. Despite this progress, several cities are still facing acute air pollution episodes, with various urban areas frequently exceeding air quality levels allowed by the European legal standards and WHO guidelines. In this paper, six European cities/ regions (Bristol, UK; Amsterdam, NL; Sosnowiec, PL; Ljubljana, SI; Aveiro, PT; Liguria, IT) are studied in terms of air quality, namely particulate matter, nitrogen dioxide and ozone. The concentrations trends from 2008 to 2017 in the different typology of monitoring stations are addressed, together with the knowledge of daily, weekly and seasonal pollution patterns to better understand the city specific profiles and to characterize pollutant dynamics and variations in multiple locations. Additionally, an analysis of the duration and severity of air pollution episodes is also discussed, followed by an analysis of the fulfillment of the legislated limit values. Each of our 6 case study locations face different air pollution problems, but all these case studies have made some progress in reducing ambient concentrations. In Bristol, there have been strong downward trends in many air pollutants, but the levels of NO2 remain persistently high and of concern. In recent years, decreasing concentration levels point to some success of Amsterdam air quality policies. PM10 exceedances are a seasonal pollution problem in Ljubljana, Sosnowiec and Aveiro region (even if with different levels of severity). While, exceedances of NO2 and O3 concentrations are still problematic in Liguria region. The main findings of this paper are particular relevant to define and compare future citizen-led strategies and policy initiatives that may be implemented to improve and fulfill the EU legislation and the WHO guidelines.
... These reductions of SO2 emissions were reflected in the decreasing ambient SO2 ( -3% to -8%/yr) concentrations at 15 sites during the study period, 1994-2007 (Paper I). Comparable downward trends have been reported in both urban and rural environments in Europe (Jones and Harrison, 2011;Henschel et al., 2013;Guerreiro et al., 2014;Crippa et al., 2016;Colette et al., 2016) and In Finnish background areas, the SO2 concentration level is around 0.5-1 µg/m 3 . Nowadays (2016)(2017)(2018) in Finnish background areas, the lowest SO2 concentrations (hourly, daily, annual) are observed at Utö, and the highest are in northernmost Lapland (Raja-Joosepppi and Kevo) under the influence of the ongoing and still partly obscure emissions in the Kola Peninsula (e.g. ...
Thesis
Ameisensäure (HCOOH) und Schwefeldioxid (SO2) zählen zu den wichtigsten organischen Säuren beziehungsweise anorganischen Säurevorläufern, die gasförmig in der Atmosphäre vorkommen. Erste detaillierte simultane Messungen von Ameisensäure und Schwefeldioxid in Emissionsfahnen urbaner Ballungsräume in Europa und Ostasien werden in dieser Arbeit vorgestellt. Als Luftschadstoffe wirken sich beide Gase auf die Gesundheit der Bevölkerung aus, zum Beispiel durch Beeinträchtigung der Atemwege und des Herzkreislaufsystems. Zudem beeinflussen sie die Bildung und Eigenschaften von Aerosolen und Wolken und tragen zu saurem Regen bei, wodurch die Flora und Fauna geschädigt werden kann. Zur Reduktion der Luftschadstoffe ist ein genaues Verständnis über ihre Quellen, Senken und Transformationen während des Transports notwendig, wozu flugzeuggetragene In-situ Messungen in Emissionsfahnen urbaner Ballungszentren beitragen können. Im Rahmen des Projekts EMeRGe (Effect of Megacities on the transport and transformation of pollutants on the Regional to Global scales) wurden an Bord des Forschungsflugzeugs HALO während zweier Messkampagnen von Oberpfaffenhofen bei München im Juli 2017 und von Tainan (Taiwan) im März 2018 Messungen durchgeführt. Die Messungen fanden mit einem Chemischen-Ionisations-Ionenfallen-Massenspektrometer (Chemical Ionization Ion Trap Mass Spectrometer (CI-ITMS)) unter Verwendung einer CO3(-) Ionenchemie statt. Kalibrierungen wurden durchgeführt, indem dem Probenfluss isotopisch markiertes SO2 aus einem Gasstandard und HCOOH aus einer Permeationsquelle zugesetzt wurden. Im Zuge der EMeRGe-Kampagnen konnten Schadstofffahnen der Metropolregionen London (UK), Benelux (BE, NL, LU), Ruhrgebiet (DE), Po-Ebene, Rom (IT), Paris, Marseille (FR) und Barcelona (ES) in Europa sowie Taichung, Taipeh (Taiwan), Pearl Flussdelta, Jangtse Flussdelta (China), Manila (Republik der Philippinen), Seoul (Republik Korea), Nagoya, Osaka und Tokio (Japan) in Asien vermessen werden. Die Entfernungen zu den jeweiligen Quellregionen betrugen zwischen 500 m und 2000 km. Eine Zuordnung der vermessenen Emissionsfahnen zu den Quellregionen wurde unter Verwendung von Luftmassentrajektorien- und Emissionsdispersionsberechnungen sowie Perfluorcarbon-Tracer-Experimenten für ausgewählte Fälle hergestellt. Zur Charakterisierung der Schadstofffahnen wurden Emissionsverhältnisse (emission ratios (ER)), Korrelationsanalysen zwischen Spurengasen und zwischen Spurengasen und Aerosoleigenschaften sowie Kohlenwasserstoff-Tracer herangezogen, wie Benzol, Acetonitril und Isopren für Emissionen aus anthropogenen und biogenen Quellen sowie Verbrennung von Biomasse. Generell wurde herausgefunden, dass das ER von HCOOH/CO mit dem Alter der Emissionsfahnen zunimmt und in Europa bzw. Asien zwischen 0.05 - 0.57 und 0.03 - 0.08 liegt. Weiter wurde festgestellt, dass die Erhöhungen durch eine sekundäre Bildung von HCOOH in den Emissionsfahnen hauptsächlich durch Oxidation der Isopren-Emissionen verursacht sind. Die ermittelten HCOOH-Bildungsraten betragen 18.5 pmol mol-1 HCOOH / nmol mol-1 CO pro Stunde und 1.25 pmol mol-1 HCOOH / nmol mol-1 CO pro Stunde in Schadstofffahnen in Europa bzw. Asien. Die höheren HCOOH-Produktionsraten in den europäischen Emissionsfahnen sind auf die höheren Isopren-Emissionen in den Quellregionen in Europa im Juli zurückzuführen, verglichen mit den Werten in Asien im März. Die Zunahme von HCOOH mit dem Alter der Emissionsfahne wird auch durch Simulationen mit dem Chemie-Transport-Modell WRF-Chem für den Fall der Manila-Emissionsfahne gezeigt. Die höchste HCOOH-Produktionsrate (33 pmol mol-1 HCOOH / nmol mol-1 CO pro Stunde) wurde in einer Rauchfahne eines großen europäischen Waldbrandes im Jahr 2017 in der Nähe von Marseille, aufgrund des sehr hohen Isopren-Gehalts in der Fahne, beobachtet. Die ermittelten ER von SO2/CO nehmen generell mit dem Alter der Emissionsfahnen ab. Grund dafür ist die Oxidation von SO2 zu H2SO4 (Schwefelsäure), was zu Bildung und Wachstum von Sulfat-Aerosolen in den Schadstofffahnen führt. Eine SO2-Lebensdauer von 10 bis 15 Stunden bzw. 30 bis 43 Stunden konnte für Emissionsfahnen in Europa bzw. Asien abgeleitet werden. Die gemessenen Mischungsverhältnisse von HCOOH und SO2 korrelieren stark mit der Konzentration von organischem Aerosol und Sulfat-Aerosol in den Schadstofffahnen, was auf ihre wichtige Rolle bei der Aerosolbildung und dem Aerosolwachstum hinweist. Die HCOOH- und SO2-Messungen werden auch mit früheren Flugzeugmessungen und mit numerischen Modellsimulationen der Chemie-Klima- und Chemie-Transport-Modelle MECO(n) und WRF-Chem verglichen. Dabei wurde herausgefunden, dass die HCOOH-Mischungsverhältnisse in den Emissionsfahnen in beiden Modellen stark unterschätzt werden. Die vorliegenden Messungen zeigen die zunehmende Bedeutung organischer Emissionen wie HCOOH im Vergleich zu den regulierten klassischen Emissionen SO2 und NOy für die Eigenschaften von Aerosolen, Wolken und Niederschlägen.
Article
The project „Healthy people in a healthy climate” developed together with actors from science, civil society and state agencies in Styria consensual climate and public health goals and explored possi-ble policies. Consensual political goals bear the potential to induce new and solid political alliances in the sense of discourse coalitions between different actors, and to guide these alliances. The project focused on climate change mitigation, which is often associated with sacrifice, impeding the enact-ment and implementation of respective policies. By connecting climate protection and public health in the sense of new discourse coalitions, climate change mitigation policies could gain legitimacy due to their framing as health issues. Such a framing could support underlining the positive effects of such policies on the individual and societal quality of life, which climate protection is enabling. Against this backdrop, 21 interviews with actors from Styria and beyond were conducted, positive visions of a future climate-friendly society in selected areas were screened in the scientific literature, and health impacts of selected climate protection and public health policy goals were quantified with the help of a literature research. Among the policies that actors mentioned and that are described in the literature, policies regarding food and mobility have the greatest potential for synergies. Policies in these two areas can contribute substantially to climate change mitigation, and according to the lit-erature, there is solid evidence that such policies have a positive public health impact. Further areas of climate protection policies are less conducive to such synergies for three reasons: because data on public health impacts are insufficient; or public health impacts can hardly or cannot be quantified or quantitatively assessed without ambitious modeling approaches; or corresponding climate protection policies are unlikely to have substantial positive public health impacts by themselves. The project is recommending to develop a discourse coalition between climate and health actors in two regards: increasing the share of plant based food at the expense of animal based food, and more active mobil-ity at the expense of motorized individual mobility. Structural changes in the sense of degrowth re-garding urban design, solidarity, deceleration, health promotion and regionalization should be in the center.
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The great Isfahan has experienced an almost fast industrialization during the last years. The different factories and industries near that, cause one of the important environmental problems, air pollution, which has not enough investigated before in this area. The hourly, diurnal and seasonal variations of SO2 concentration as one of the most dangerous air pollutants, are studied to clarify the rule of industry on the air pollution problem. The data had been measured continuously from April 2006 to March 2007 at two stations, Lale & Azadi. The air pollution concentrations in an urban area have a close relationship with meteorological factors. Hence, the variation of SO2 concentration is analysed respect to the meteorological factors such as temperature, relative humidity, wind speed, solar radiation, and pressure. Moreover, the studied air pollutant is also statistically investigated through correlation analysis and step-wise multiple linear regression equation. It was observed that electric power plant near the Isfahan, Montazeri, has significant effects on the SO2 concentration in the east and north of Isfahan. Long-term pattern of Isfahan winds which is westerly during the winter and spring, and easterly during the summer and autumn, was recognized as one of another important factors influenced the SO2 concentration variations. It is also achieved that meteorological factors have considerable contribution, R² = 52%, on the SO2 concentration variation and temperature has largest effect among the others.
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Background This study provides an assessment of the health effects due to exposure to particulate matter PM2.5 (diameter < 2.5 µm that cause the air to appear hazy when levels are elevated) in three medium size cities of north western Mexico (Los Mochis, Culiacan and Mazatlan). We computed the total avoidable premature mortality, avoidable cardiovascular disease, gains in life expectancy, as well as the economic costs by air contamination corresponding to PM2.5. To achieve this goal, the Health Impacts Assessment (HIA) methodology provided by the European Aphekom Project was used. People in these cities are exposed to high PM2.5 concentrations that exceed limits implemented in domestic and international guidelines. Results We determined the cost of the PM2.5 pollutant associated with health outcomes under two different scenarios: Official Mexican Standard (NOM, Spanish acronym) and World Health Organization (WHO). The mean PM2.5 concentrations in 2017 were 22.8, 22.4 y 14.1 µg/m³ for the cities Los Mochis, Mazatlan and Culiacan, respectively. The mean avoidable mortality for all causes associated to the exposure to PM2.5 in the three cities was 638 for the NOM scenario (i.e., with a reduction to 12 µg/m³) compared to 739 for the WHO scenario (reduction to 10 µg/m³). Complying with the WHO guideline of 10 µg/m³ in annual PM2.5 mean would add up to 15 months of life expectancy at age 30, depending on the city. Conclusions The mean economic cost per year of the PM2.5 effects on human life in these three cities was $600 (NOM scenario) and $695 million dollars (WHO scenario). Effective public health and industrial policy interventions are socially advantageous and cost-saving to promote better health.
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NASA recently extended the Modern-Era Retrospective Analysis for Research and Application (MERRA) with an atmospheric aerosol reanalysis which includes five particulate species: sulfate, organic matter, black carbon, mineral dust and sea salt. The MERRA Aerosol Reanalysis (MERRAero) is an innovative tool to study air quality issues around the world for its global and constant coverage and its distinction of aerosol speciation expressed in the form of aerosol optical depth (AOD). The purpose of this manuscript is to apply MERRAero to the study of urban air pollution at the global scale by analyzing the AOD over a period of 13 years (2003–2015) and over a selection of 200 of the world's most populated cities in order to assess the impacts of urbanization, industrialization, air quality regulations and regional transport which affect urban aerosol load. Environmental regulations and the recent global economic recession helped to decrease the AOD and sulfate aerosols in most cities of North America, Europe and Japan. Rapid industrialization in China over the last two decades resulted in Chinese cities having the highest AOD values in the world. China has nevertheless recently implemented emission control measures, which are showing early signs of success in many cities of Southern China, where AOD decreased substantially over the last 13 years. The AOD over South American cities, dominated by carbonaceous aerosols, also decreased over the last decade due to an increase in commodity prices which slowed deforestation activities in the Amazon rainforest. At the opposite, recent urbanization and industrialization in India and Bangladesh resulted in a strong increase of AOD, sulfate and carbonaceous aerosols in most cities of these two countries. The AOD over most cities in Northern Africa and Western Asia changed little over the last decade. Emissions of natural aerosols, which cities in these two regions tend to be mostly impacted by, don't tend to fluctuate significantly on an annual basis.
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Sulfur dioxide (SO2) is considered the most widespread pollutant that threatens human and environmental health. Seasonal variation revealed higher levels of SO2 on cold days. The variations of the day revealed a higher concentration of SO2 indicating traffic influence, especially during peak hours. The analysis of hourly/daily/annual means identified an increasing trend in SO2 concentrations, implying that emission control systems and the technological improvement of engines and fuels were not sufficient and, therefore, points to the need for better subsidy mechanisms for the control of pollutants and effective emission reduction strategies, environmental agencies, should prioritize considering local realities.
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The analysis of gaseous criteria pollutants in the Bangkok Metropolitan Region (BMR), Thailand, from 2010 to 2014 reveals that while the hourly concentrations of CO, SO2 and NO2 were mostly within the National Ambient Air Quality Standards (NAAQs) of Thailand, the hourly concentrations of O3 frequently exceeded the standard. The results reveal that the problem of high O3 concentration continuously persisted in this area. The O3 photolytic rate constant (j1) for BMR calculated based on assuming a photostationary state ranged from 0.008 to 0.013s⁻¹, which is similar to the calculated j1 using the NCAR TUV model (0.021±0.0024s⁻¹). Interconversion between O3, NO and NO2 indicates that crossover points between the species occur when the concentration of NOx ( = NO + NO2) is ∼ 60ppb. Under a low-NOx regime ([NOx]<60ppb), O3 is the dominant species, while, under a high-NOx regime ([NOx] >60ppb), NO dominates. Linear regression analysis between the concentrations of Ox ( = O3+NO2) and NOx provides the role of local and regional contributions to Ox. During O3 episodes ([O3]hourly >100ppb), the values of the local and regional contributions were nearly double of those during non-episodes. Ratio analysis suggests that the major contributors of primary pollutants over BMR are mobile sources. The air quality index (AQI) for BMR was predominantly good to moderate; however, unhealthy O3 categories were observed during episode conditions in the region.
Article
Trace elements in fine particulate matter (PM2.5) exacerbate human health problems owing to exposure to PM2.5 and its toxic components. Samples of PM2.5 collected in Seoul, Republic of Korea, during typical haze episodes between November 2017 and April 2018, were analyzed for trace elements and Pb isotopes to characterize PM2.5 trace elements and their sources. The concentrations of Cu, Zn, As, Cd, Sb, Tl, and Pb showed statistically significant increases with ambient PM2.5 levels under their negative relationships with wind speed. High enrichment factor values provided evidence of significant inputs from anthropogenic sources. We assigned the dominant source regions of PM2.5 mass and chemical composition during individual sampling periods by coupling the Pb isotopic composition with the air mass back trajectories. The results identified three major categories of domestic, Chinese, and mixed domestic/Chinese source contributions, accounting for about 39%, 38%, and 21%, respectively, during the entire sampling period, which reflects a significant Chinese contribution. Principal component analysis (PCA) identified the major domestic sources for individual elements: coal/oil combustion and vehicle exhaust (Zn, As, Cd, Sb, Tl, and Pb), non-exhaust traffic emissions (Cu and Sb), and soil/road dust (Fe and Mn). Using a Pb isotopic mixing model, the relative contributions from coal combustion, oil combustion, and vehicle exhaust to associated trace elements were estimated to be 35 ± 11%, 35 ± 8%, and 29 ± 16%, respectively. Our results highlight that beyond addressing climate change, driving the transition from fossil fuels to renewable energy sources in the power, heat, and road transport sectors can help greatly reduce air pollution and achieve healthy environment.
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The analysis of thePM10particle measurements at the two major urban areas of Greece, Athens and Thessaloniki, showed that the mean monthlyPM10concentrations at the central urban stations, are on the average about twice as high than the corresponding ones at the examined peripheral stations. The distribution of the dailyPM10values shows significant violations of the EU air quality standards, especially in the central urban stations. At the peripheral stations comparable distributions ofPM10concentration values are found. The highestPM 10hourly values are recorded at the central urban stations during the cold semester of the year and during the morning hours. The scatter-plot diagrams of the central urban dailyPM10mean values versus the peripheral stations show important influence of the regional aerosol episodes on the measuredPM10concentrations in the urban areas of Athens and Thessaloniki, which is stronger in Athens and during the warm semester of the year. The PM10 diurnal variation pattern are quite similar with the corresponding variations observed for primary urban pollutants, like the morning and the evening peaks, but also at the peripheral stations exhibit a broad mid-day peak indicating elevated rural backgroundPM10levels. Additional daily measurements at the rural station of Aliartos in Central Greece give PM10 average values around 30 μg m-3, comparable to the corresponding averagePM10values of the peripheral stations in Athens and Thessaloniki. Such high rural backgroundPM10daily mean values could lead to average annual values higher than the corresponding EU PM10 standard (40 μg m-3) and should be taken into account in the formulation of the local pollution abatement strategies as they represent about the half of the averagePM10levels measured at the central urban stations of both examined urban areas.
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Since the mid-1970s, episodes of high ozone concentrations tend to occur more often on weekends rather than weekdays in California's South Coast Air Basin (SoCAB). These weekend episodes seem counterintuitive because air pollutant emissions estimates are reduced for weekends (relative to weekdays).1,2,3,4,5 If weekend emissions are reduced, then why are ozone episodes more likely to occur on weekends? And, what does the so-called "weekend effect" imply for development of effective ozone control strategies in the SoCAB? It is extremely unlikely that systematic weekday-to- weekend (WD-WE) differences in weather tendencies could explain the weekend effect. Rather, differences in the relative proportions of ambient air pollutants correlate with weekend ozone peaks.6 Therefore, researchers postulate that an aggregate shift in human activities on weekends, which causes certain pollutants to be emitted in disproportionately lesser amounts, is the most plausible explanation for the weekend effect.7,8
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This paper studies the effect of a Catalyzed Diesel Particle Filter (CDPF) on the emission profile of a Euro 4 diesel vehicle operated on low sulfur fuel and lubrication oil. The vehicle was tested in its original configuration and with the CDPF retrofitted in place of its main underbody catalyst. Experiments included steady state tests, the certification cycle and real-world high speed transient driving conditions. Measurements included total particle mass collected on Teflon-coated filters, total particle number measured by a condensation particle counter, size distributions determined by a Scanning Mobility Particle Sizer and chemical analysis of the mass collected for elemental and organic carbon, ions, PAHs, and trace elements. Results showed that the vehicle complies with the Euro 4 emission limits when tested over the type-approval NEDC, but it emits more nitrogen oxides and, in some cases, more particulate matter when tested over real-world test cycles. The CDPF reduces PM mass emission up to 90-95% and particle number by 2-3 orders of magnitude. However, nucleation of volatile species may occur under specific conditions of the engine exhaust dilution and sampling system and may mask this reduction. Emissions of chemical elements, elemental and organic carbon were also substantially reduced by the CDPF, while moderate reductions of ionic species and PAHs were observed.
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openair is an R package primarily developed for the analysis of air pollution measurement data but which is also of more general use in the atmospheric sciences. The package consists of many tools for importing and manipulating data, and undertaking a wide range of analyses to enhance understanding of air pollution data. In this paper we consider the development of the package with the purpose of showing how air pollution data can be analysed in more insightful ways. Examples are provided of importing data from UK air pollution networks, source identification and characterisation using bivariate polar plots, quantitative trend estimates and the use of functions for model evaluation purposes. We demonstrate how air pollution data can be analysed quickly and efficiently and in an interactive way, freeing time to consider the problem at hand. One of the central themes of openair is the use of conditioning plots and analyses, which greatly enhance inference possibilities. Finally, some consideration is given to future developments.
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In many large cities of Europe standard air quality limit values of particulate matter (PM) are exceeded. Emissions from road traffic and biomass burning are frequently reported to be the major causes. As a consequence of these exceedances a large number of air quality plans, most of them focusing on traffic emissions reductions, have been implemented in the last decade. In spite of this implementation, a number of cities did not record a decrease of PM levels. Thus, is the efficiency of air quality plans overestimated? Do the road traffic emissions contribute less than expected to ambient air PM levels in urban areas? Or do we need a more specific metric to evaluate the impact of the above emissions on the levels of urban aerosols? This study shows the results of the interpretation of the 2009 variability of levels of PM, Black Carbon (BC), aerosol number concentration (N) and a number of gaseous pollutants in seven selected urban areas covering road traffic, urban background, urban-industrial, and urban-shipping environments from southern, central and northern Europe. The results showed that variations of PM and N levels do not always reflect the variation of the impact of road traffic emissions on urban aerosols. However, BC levels vary proportionally with those of traffic related gaseous pollutants, such as CO, NO<sub>2</sub> and NO. Due to this high correlation, one may suppose that monitoring the levels of these gaseous pollutants would be enough to extrapolate exposure to traffic-derived BC levels. However, the BC/CO, BC/NO<sub>2</sub> and BC/NO ratios vary widely among the cities studied, as a function of distance to traffic emissions, vehicle fleet composition and the influence of other emission sources such as biomass burning. Thus, levels of BC should be measured at air quality monitoring sites. During morning traffic rush hours, a narrow variation in the N/BC ratio was evidenced, but a wide variation of this ratio was determined for the noon period. Although in central and northern Europe N and BC levels tend to vary simultaneously, not only during the traffic rush hours but also during the whole day, in urban background stations in southern Europe maximum N levels coinciding with minimum BC levels are recorded at midday in all seasons. These N maxima recorded in southern European urban background environments are attributed to midday nucleation episodes occurring when gaseous pollutants are diluted and maximum insolation and O<sub>3</sub> levels occur. The occurrence of SO<sub>2</sub> peaks may also contribute to the occurrence of midday nucleation bursts in specific industrial or shipping-influenced areas, although at several central European sites similar levels of SO<sub>2</sub> are recorded without yielding nucleation episodes. Accordingly, it is clearly evidenced that N variability in different European urban environments is not equally influenced by the same emission sources and atmospheric processes. We conclude that N variability does not always reflect the impact of road traffic on air quality, whereas BC is a more consistent tracer of such an influence. However, N should be measured since ultrafine particles (<100 nm) may have large impacts on human health. The combination of PM<sub>10</sub> and BC monitoring in urban areas potentially constitutes a useful approach for air quality monitoring. BC is mostly governed by vehicle exhaust emissions, while PM<sub>10</sub> concentrations at these sites are also governed by non-exhaust particulate emissions resuspended by traffic, by midday atmospheric dilution and by other non-traffic emissions.
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Efforts to understand and mitigate the health effects of particulate matter (PM) air pollution have a rich and interesting history. This review focuses on six substantial lines of research that have been pursued since 1997 that have helped elucidate our understanding about the effects of PM on human health. There has been substantial progress in the evaluation of PM health effects at different timescales of exposure and in the exploration of the shape of the concentration-response function. There has also been emerging evidence of PM-related cardiovascular health effects and growing knowledge regarding interconnected general pathophysiological pathways that link PM exposure with cardiopulmonary morbidity and mortality. Despite important gaps in scientific knowledge and continued reasons for some skepticism, a comprehensive evaluation of the research findings provides persuasive evidence that exposure to fine particulate air pollution has adverse effects on cardiopulmonary health. Although much of this research has been motivated by environmental public health policy, these results have important scientific, medical, and public health implications that are broader than debates over legally mandated air quality standards.
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The Po valley in northern Italy is renowned for its high air pollutant concentrations. Measurements of air pollutants from a background site in Modena, a town of 200 thousand inhabitants within the Po valley, are analysed. These comprise hourly data for CO, NO, NO(2), NO(x), and O(3), and daily gravimetric equivalent data for PM(10) from 1998-2010. The data are analysed in terms of long-term trends, annual, weekly and diurnal cycles, and auto-correlation and cross-correlation functions. CO, NO and NO(2) exhibit a strongly traffic-related pattern, with daily peaks at morning and evening rush hour and lower concentrations over the weekend. Ozone shows an annual cycle with a peak in July due to local production; notwithstanding the diurnal cycle dominated by titration by nitrogen oxide, the decreasing long term trend in NO concentration did not affect the long term trend in O(3), whose mean concentration remained steady over the sampling period. PM(10) shows a strong seasonality with higher concentration in winter and lower concentration in summer and spring. Both PM(10) and ozone show a marked weekly cycle in summer and winter respectively. Regressions of PM(10) upon NO(x) show a consistently greater intercept in winter, representing higher secondary PM(10) in the cooler months of the year. There is a seasonal pattern in primary PM(10) to NO(x) ratios, with lower values in winter and higher values in summer, but the reasons are unclear.
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The unification of East and West Germany in 1990 resulted in sharp decreases in emissions of major air pollutants. This change in air quality has provided an opportunity for a natural experiment to evaluate the health impacts of air pollution. We evaluated airborne particle size distribution and gaseous co-pollutant data collected in Erfurt, Germany, throughout the 1990s and assessed the extent to which the observed changes are associated with changes in the two major emission sources: coal burning for power production and residential heating, and motor vehicles. Continuous data for sulfur dioxide, total suspended particulates (TSP), nitric oxide, carbon monoxide, and meteorologic parameters were available for 1990-1999, and size-selective particle number and mass concentration measurements were made during winters of 1991 and 1998. We used hourly profiles of pollutants and linear regression analyses, stratified by year, weekday/weekend, and hour, using NO and SO(2) as markers of traffic- and heating-related combustion sources, respectively, to study the patterns of various particle size fractions. Supplementary data on traffic and heating-related sources were gathered to support hypotheses linking these sources with observed changes in ambient air pollution levels. Substantially decreased (19-91%) concentrations were observed for all pollutants, with the exception of particles in the 0.01-0.03 microm size range (representing the smallest ultrafine particles that were measured). The number concentration for these particles increased by 115% between 1991 and 1998. The ratio of these ultrafine particles to TSP also increased by more than 500%, indicating a dramatic change in the size distribution of airborne particles. Analysis of hourly concentration patterns indicated that in 1991, concentrations of SO(2) and larger particle sizes were related to residential heating with coal. These peaks were no longer evident in 1998 due to decreases in coal consumption and consequent decreased emissions of SO(2) and larger particles. These decreases in coal combustion and the decreased concentrations of SO(2) and particles of larger size classes may have led to decreased particle scavenging and may be partially responsible for the observed increases in ultrafine particles. Traffic-related changes, such as increased numbers of trucks and increased use of diesel vehicles in Erfurt, were also associated with increased number concentrations of ultrafine particles. Morning particle peaks of all sizes were associated with NO and CO (markers for traffic) in both the 1991 and 1998 periods. There were significant differences in the ultrafine particle levels for morning hours between 1991 and 1998, suggesting that traffic was the cause of this increase.
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This article develops and assesses novel indicators of respiratory and other morbidity and mortality following London's lethal smog in the winter of 1952. Public health insurance claims, hospital admission rates for cardiac and respiratory disease, pneumonia cases, mortality records, influenza reports, temperature, and air pollutant concentrations are analyzed for December-February 1952-1953 and compared with those for the previous year or years. Mortality rates for the smog episode from December 1952 to February 1953 were 50-300% higher than the previous year. Claims that the smog only elevated health risks during and immediately following the peak fog 5-9 December 1952 and that an influenza epidemic accounted fully for persisting mortality increases in the first 2 months of 1953 are rejected. We estimate about 12,000 excess deaths occurred from December 1952 through February 1953 because of acute and persisting effects of the 1952 London smog. Pollution levels during the London smog were 5-19 times above current regulatory standards and guidelines and approximate current levels in some rapidly developing regions. Ambient pollution in many regions poses serious risks to public health.
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Sulphur dioxide (SO(2)) was associated with hospital admissions for asthma in children in the original APHEA study, but not with other respiratory admissions. To assess the association between daily levels of SO(2) and daily levels of respiratory admissions in a larger and more recent study. Time series of daily counts of hospital emergency admissions were constructed for asthma at ages 0-14 years and 15-64 years, COPD and asthma, and all respiratory admissions at ages 65+ years in the cities of Birmingham, London, Milan, Paris, Rome, Stockholm, and in the Netherlands for periods of varying duration between the years 1988 and 1997. A two stage hierarchical modelling approach was used. In the first stage generalised additive Poisson regression models were fitted in each city controlling for weather and season. These results were then combined across cities in a second stage ecological regression that looked at potential effect modifiers. For an increase of 10 micro g/m(3) of SO(2) the daily number of admissions for asthma in children increased 1.3% (95% CI 0.4% to 2.2%). Effect modification among cities by levels of other air pollutants or temperature was not found. The SO(2) effect disappeared after controlling for PM(10) or CO, but correlation among these pollutants was very high. Other respiratory admissions were not associated with SO(2). SO(2) is associated with asthma admissions in children, indicating that reduction in current air pollution levels could lead to a decrease in the number of asthma admissions in children in Europe.
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Efforts to understand and mitigate thehealth effects of particulate matter (PM) air pollutionhave a rich and interesting history. This review focuseson six substantial lines of research that have been pursued since 1997 that have helped elucidate our understanding about the effects of PM on human health. There hasbeen substantial progress in the evaluation of PM health effects at different time-scales of exposure and in the exploration of the shape of the concentration-response function. There has also been emerging evidence of PM-related cardiovascular health effects and growing knowledge regarding interconnected general pathophysiological pathways that link PM exposure with cardiopulmonary morbidiity and mortality. Despite important gaps in scientific knowledge and continued reasons for some skepticism, a comprehensive evaluation of the research findings provides persuasive evidence that exposure to fine particulate air pollution has adverse effects on cardiopulmonaryhealth. Although much of this research has been motivated by environmental public health policy, these results have important scientific, medical, and public health implications that are broader than debates over legally mandated air quality standards.
Article
Two three dimensional Eulerian air quality models, PMCAMx and UAM-AERO are used to predict the concentrations of various pollutants in the Greater Athens Area (GAA) during the episode of June 22-26, 2003. The predicted levels of gases and aerosol pollutants are compared with measured concentrations from monitoring stations, in order to evaluate the performance of the models. Comparison of the results reveals that PMCAMx simulated the ozone diurnal pattern better than UAM-AERO, as the predicted by UAM-AERO maximum daytime concentrations were much higher than those of PMCAMx and way above the measured ones. PMCAMx also shows signs of superiority in terms of its ability to predict the NO 2 and NO concentrations. Two sets of simulations, one with both anthropogenic and biogenic emissions and one without biogenic emissions were performed. Comparison of the two simulations reveals the important role that biogenic emissions play in the formation of O 3 , NOx and secondary aerosols. Additional simulations with PMCAMx show that the concentrations of all the pollutants depict a highly non-linear behaviour, when anthropogenic VOC emissions are reduced in the GAA.
Article
Different monitoring parameters (PM mass concentrations, number–size distribution, black carbon, gaseous pollutants, and chemical composition, among others) are currently used in air quality studies. Urban aerosols are the result of several sources and atmospheric processes, which suggests that a single monitoring technique is insufficient to quantitatively evaluate all of them.This study assesses the suitability of a number of monitoring techniques (PM mass concentrations, number and size distribution of ultra-fine particles, levels of gaseous pollutants, and a complete chemical characterization of PM10 and PM2.5) by examining the response of those techniques to the different emission sources and/or atmospheric processes affecting an urban Mediterranean area (Barcelona, NE Spain).The results of this work reveal that the PM mass, the number concentration and the chemical composition give different, but complementary, information. Whereas the mineral matter, a key atmospheric aerosol component across the Mediterranean, is not properly quantitatively assessed by measuring sub-micrometric particles, the monitoring of the number concentration is indispensable to interpret the origin of specific aerosol episodes. Furthermore, the chemical composition yields very relevant information to deduce the causes of specific pollution episodes.The number concentration of ultra-fine particles in urban areas is strongly dependent upon vehicle exhaust emissions, which may cause adverse health impacts. Moreover, urban Mediterranean environments are favourable to produce nucleation-mode particles (
Article
The paper presents an objective air quality classification scheme for observed ozone (O3), nitrogen dioxide (NO2), sulphur dioxide (SO2) and particulate matter (PM10) time series in Germany. The classification is based on the medians of daily average concentration and relative daily variation. Six (O3 and NO2) and five (SO2 and PM10) different regimes were identified by means of hierarchical clustering. The stability of the clusters in relation to variable scaling and transformation was ensured by a cross-validation test based on re-sampling. Quick classification rules were developed, which permit a rapid and easy classification of any further observed or modelled annual time series. The climatological properties of the defined regimes were examined in terms of the mean and maximum values, as well as inter-annual, yearly, weekly and daily variability. The polluted regimes are characterised by a pronounced weekly cycle. O3 and NO2 classifications agree reasonably well for most stations, but the range of SO2 and PM10 concentrations is large within specific O3 regimes.
Article
Despite their significant role in source apportionment analysis, studies dedicated to the identification of tracer elements of emission sources of atmospheric particulate matter based on air quality data are relatively scarce. The studies describing tracer elements of specific sources currently available in the literature mostly focus on emissions from traffic or large-scale combustion processes (e.g. power plants), but not on specific industrial processes. Furthermore, marker elements are not usually determined at receptor sites, but during emission. In our study, trace element concentrations in PM10 and PM2.5 were determined at 33 monitoring stations in Spain throughout the period 1995–2006. Industrial emissions from different forms of metallurgy (steel, stainless steel, copper, zinc), ceramic and petrochemical industries were evaluated. Results obtained at sites with no significant industrial development allowed us to define usual concentration ranges for a number of trace elements in rural and urban background environments. At industrial and traffic hotspots, average trace metal concentrations were highest, exceeding rural background levels by even one order of magnitude in the cases of Cr, Mn, Cu, Zn, As, Sn, W, V, Ni, Cs and Pb. Steel production emissions were linked to high levels of Cr, Mn, Ni, Zn, Mo, Cd, Se and Sn (and probably Pb). Copper metallurgy areas showed high levels of As, Bi, Ga and Cu. Zinc metallurgy was characterised by high levels of Zn and Cd. Glazed ceramic production areas were linked to high levels of Zn, As, Se, Zr, Cs, Tl, Li, Co and Pb. High levels of Ni and V (in association) were tracers of petrochemical plants and/or fuel-oil combustion. At one site under the influence of heavy vessel traffic these elements could be considered tracers (although not exclusively) of shipping emissions. Levels of Zn–Ba and Cu–Sb were relatively high in urban areas when compared with industrialised regions due to tyre and brake abrasion, respectively.
Article
The least squares estimator of a regression coefficient β is vulnerable to gross errors and the associated confidence interval is, in addition, sensitive to non-normality of the parent distribution. In this paper, a simple and robust (point as well as interval) estimator of β based on Kendall's [6] rank correlation tau is studied. The point estimator is the median of the set of slopes (Yj - Yi)/(tj-ti) joining pairs of points with ti ≠ ti, and is unbiased. The confidence interval is also determined by two order statistics of this set of slopes. Various properties of these estimators are studied and compared with those of the least squares and some other nonparametric estimators.
Article
Regression analysis is usually carried out under the hypothesis that one of the variables is normally distributed with constant variance, its mean being a function of the other variables. This assumption is not always satisfied, and in most cases difficult to ascertain.
Article
Average 21st century concentrations of urban air pollutants linked to cardiorespiratory disease are not declining, and commonly exceed legal limits. Even below such limits, health effects are being observed and may be related to transient daytime peaks in pollutant concentrations. With this in mind, we analyse >52,000 hourly urban background readings of PM10 and pollutant gases throughout 2007 at a European town with legal annual average concentrations of common pollutants, but with a documented air pollution-related cardiorespiratory health problem, and demonstrate the hourly variations in PM10, SO2, NOx, CO and O3. Back-trajectory analysis was applied to track the arrival of exotic PM10 intrusions, the main controls on air pollutants were identified, and the typical hourly pattern on ambient concentrations during 2007 was profiled. Emphasis was placed on “worst case” data (>90th percentile), when health effects are likely to be greatest. The data show marked daytime variations in pollutants result from rush-hour traffic-related pollution spikes, midday industrial SO2 maxima, and afternoon O3 peaks. African dust intrusions enhance PM10 levels at whatever hour, whereas European PM incursions produce pronounced evening peaks due to their transport direction (across an industrial traffic corridor). Transient peak profiling moves us closer to the reality of personal outdoor exposure to inhalable pollutants in a given urban area. We argue that such an approach to monitoring data potentially offers more to air pollution health effect studies than using only 24 h or annual averages.
Article
Numerous epidemiological studies have found a link between air pollution and health. We are reviewing a collection of published intervention studies with particular focus on studies assessing both improvements in air quality and associated health effects. Interventions, defined as events aimed at reducing air pollution or where reductions occurred as a side effect, e.g. strikes, German reunification, from the 1960s onwards were considered for inclusion. This review is not a complete record of all existing air pollution interventions. In total, 28 studies published in English were selected based on a systematic search of internet databases. Overall air pollution interventions have succeeded at improving air quality. Consistently published evidence suggests that most of these interventions have been associated with health benefits, mainly by the way of reduced cardiovascular and/or respiratory mortality and/or morbidity. The decrease in mortality from the majority of the reviewed interventions has been estimated to exceed the expected predicted figures based on the estimates from time-series studies. There is consistent evidence that decreased air pollution levels following an intervention resulted in health benefits for the assessed population. Copy available via: http://rdcu.be/mRbU
Article
This study deals with air quality monitoring in an urban region of Kolkata, consisting of residential, commercial and industrial sites having high population density and pollution. Concentrations of ambient SO2 (sulfur dioxide), NO2, (nitrogen dioxide), NH3 (ammonia) and PM10 (particulate matter passing through a size selective impactor inlet with a 50% efficiency cut-off at 10 μm aerodynamic diameter) were measured once in a week for 24 h at selected residential and industrial sites and 8 h at a commercial site. The meteorological parameters (wind speed, wind direction, rainfall, temperature and relative humidity) were collected simultaneously from the Indian Meteorological Department, Kolkata. The daily average concentrations of SO2, NO2, NH3 and PM10 were observed to be 12.3 ± 9.2, 32.5 ± 14.2, 36.3 ± 19.7 and 140.1 ± 43.1 μg/m3 at the residential site, with 21.3 ± 15.7, 49.9 ± 9.8, 34.7 ± 13.5 and 196.6 ± 88.2 μg/m3 at the industrial site, respectively. The corresponding (8 h average) values at the commercial site were 15.5 ± 11.9, 39.9 ± 17.3, 33.9 ± 13.3 and 276.1 ± 71.4 μg/m3. Winter concentrations of ambient SO2, NO2, NH3 and PM10 were observed to be higher irrespective of the monitoring sites and duration of sampling, suggesting longer residence times of these pollutants in the atmosphere during winter due to stagnant conditions and low mixing heights. The SO2/NO2 ratios at the residential, commercial and industrial sites were found to be 0.38, 0.42 and 0.43, respectively. These low SO2/NO2 ratios are indicative of major emissions from mobile sources within the city. Spearman's rank correlation analysis showed an inverse relationship between the measured gaseous and particulate pollutant concentrations with the observed wind speed, rainfall, temperature and relative humidity. The data were analyzed using varimax-rotated principal component analysis for the residential and industrial sites. In principal component analysis three factors were drawn out of the seven variables, which represent 84% of the variance. The results show that local emissions dominate the concentration of SO2, NO2, NH3, and PM10. The major sources of emissions affecting this urban area include mobile sources along with contributions from industrial sources, coal-fired power plants and domestic heating.
Article
This study is an analysis of the impacts on urban air quality of restricting the operation of passenger vehicles during the 24th Asian Games (AG). Passenger vehicles in Busan were not allowed to operate on the alternative days during the AG period. This restricted operation of passenger vehicles was enforced to improve an urban air quality in Busan during the AG period. The average usage rate of passenger vehicles under an alternate (or restricted) operation was 95.4% and thus the average traffic flow rate (vehicle operation speed) increased approximately 28.1% as compared to normal periods. We analyzed the ambient concentrations of criteria air pollutants measured at 13 air-monitoring stations in Busan (Pusan), Korea, for the three periods of “before (13–28 September 2002)”, “during (29 September–14 October 2002)” and “after (15–30 October 2002)” the AG. The 1-h, 24-h and 16-day averages or median concentrations of each classified term were compared to those of other terms. The median concentrations, based on 24-h average data of each day, of PM10, CO, NO2, and SO2 in the ambient during the alternate operation period of 16 days substantially increased as compared to the terms before or after. However, the median concentration of O3 during the AG period was slightly less than that of the term before. The ambient O3 concentrations during daytime (12:00–19:00) under alternate operation substantially increased as compared to the terms before or after. However, the ambient O3 concentrations during nighttime (22:00–07:00) under alternate operation decreased when compared to the terms before or after. For the alternate operation period of passenger vehicles, the average concentrations of PM10, NO2, SO2, and daytime O3 measured at the air-monitoring stations near the stadiums were much higher than those of the other areas excluding the stadium areas. However, average CO concentrations at the other areas were higher than those nearby the stadiums during the alternate operation period.
Article
The new airport of Athens will be constructed in the Spata area to the east of the Athens basin. In an attempt to study how the airport operation influences air quality in Athens, the wind flow and pollutant transport in the Athens basin and the Spata area are studied by applying a set of contemporary models, all constituents of the EUMAC Zooming Model (EZM): (1) the nonhydrostatic prognostic mesoscale model MEMO for simulating air flow and the dispersion of inert pollutants, and (2) two photochemical dispersion models, the three-dimensional model MARS and the three-layer model MUSE for describing the dispersion of reactive pollutants. Simulations were performed for meteorological conditions favouring the occurrence of air pollution episodes. Emphasis is put on the influence of the airport emissions on air quality assuming that the airport is operating either at its old location (Hellenikon) or at Spata. Comparison of simulation results for one selected scenario achieved with all three models reveals similar diurnal variations of nitrogen oxides in the Athens basin and the Spata area. The model results show that under conditions favoring air mass penetration from Athens to the Spata area the resulting pollutant transport causes an increase in air pollution levels without, however, leading to the exceedance of air quality standards. In the opposite case, the pollutant transport cannot have a noticeable adverse influence on the Athens air quality because of both the relatively high urban air pollution levels and the fact that the penetration depth is small.
Article
The trends in the atmospheric concentrations of the main gaseous and particulate pollutants in urban, industrial and rural environments across Finland were estimated for the period of 1994–2007. The statistical analysis was based on generalized least-squares regression with classical decomposition and autoregressive moving average (ARMA) errors, which was applied to monthly-averaged data. In addition, three alternative methods were tested. Altogether 102 pollutant time series from 42 sites were analyzed. During the study period, the concentrations of SO2, CO and NOx declined considerably and widely across Finland. The SO2 concentrations at urban and industrial sites were approaching background levels. The reductions in NOx and CO concentrations were comparable to those in national road traffic emissions. A downward trend was detected in half of the NO2 time series studied, but the reductions were not as large as would be expected on the basis of emission trends, or from NOx concentrations. For O3, neither the mean nor peak values showed large changes in background areas, but were increasing in the urban data. For PM10, five of the 12 urban time series showed decreasing mean levels. However, the highest concentrations, typically attributable to the problematic springtime street dust, did not decrease as widely. The reduction of the long-range transported major ions, mainly driven by the large-scale reduction in sulphur emissions, possibly plays a significant part in the decreases in the mean PM10 concentrations. It was shown that the handling of the serially-correlated data with the ARMA processes improved the analysis of monthly values. The use of monthly rather than annually-averaged data helped to identify the weakest trends.
Article
A receptor-oriented and a source-oriented approach are applied to assess the contribution of traffic emissions to concentration levels of fine particulate matter in Milan (Italy). Both the approaches are based on the comparison between seasonal weekends’ and weekdays’ data. Relative differences observed between Sundays’ and weekdays’ PM10 concentrations are analysed in terms of their probability distributions for the cold and warm season separately. As a consequence of the reduced circulating traffic flows, Sundays’ concentration levels are on average about 20% lower, but an increase of concentration levels is sometimes observed under unfavourable meteorological conditions. The effect of the reduced traffic on Sundays is assessed also in terms of particles’ number concentration. The results obtained by the analysis of weekly PM10 concentration data are compared to information derived from the emission inventory for traffic. From observed reduction of Sundays’ traffic flow, the corresponding expected variation in primary PM10 emissions from traffic is calculated accounting for both exhaust and non-exhaust contribution. Seasonal probability distribution of PM10 emission variations are obtained by implementing the COPERT III methodology in a Monte Carlo simulation: on Sundays estimated values of PM10 emissions always result lower than on weekdays and on average about 50% less. Based on estimated reductions for PM10 traffic emission and on observed reductions for PM10 ambient air concentrations, traffic emissions appear responsible for about 50% of the PM10 concentration levels in the urban area. This contribution is both due to exhaust and non-exhaust emissions: depending on site exposure to the traffic source, out of the 50% contribution of total traffic emissions to PM10 concentrations, a 4–40% share is estimated to come directly from the exhaust, whereas the remaining share derives from non-exhaust emissions and resuspension of soil dust.
Article
Airborne particle number concentrations and size distributions as well as CO and NOx concentrations monitored at a site within the central business district of Brisbane, Australia were correlated with the traffic flow rate on a nearby freeway with the aim of investigating differences between weekday and weekend pollutant characteristics. Observations over a 5-year monitoring period showed that the mean number particle concentration on weekdays was (8.8±0.1)×103 cm−3 and on weekends (5.9±0.2)×103 cm−3—a difference of 47%. The corresponding mean particle number median diameters during weekdays and weekends were 44.2±0.3 and 50.2±0.2 nm, respectively. The differences in mean particle number concentration and size between weekdays and weekends were found to be statistically significant at confidence levels of over 99%. During a 1-year period of observation, the mean traffic flow rate on the freeway was 14.2×104 and 9.6×104 vehicles per weekday and weekend day, respectively—a difference of 48%. The mean diurnal variations of the particle number and the gaseous concentrations closely followed the traffic flow rate on both weekdays and weekends (correlation coefficient of 0.86 for particles). The overall conclusion, as to the effect of traffic on concentration levels of pollutant concentration in the vicinity of a major road (about 100 m) carrying traffic of the order of 105 vehicles per day, is that about a 50% increase in traffic flow rate results in similar increases of CO and NOx concentrations and a higher increase of about 70% in particle number concentration.
Article
Results on interpretation of the variability of regional background PM levels in the Western Mediterranean basin (WMB) are presented. Mean PM levels recorded at Montseny, MSY (North-Eastern Spain) in the 2002–2007 period reached 17, 13 and 11 µg/m3 of PM10, PM2.5 and PM1, respectively.The daily evolution of PM levels is regulated by the breeze circulation (mountain and sea breezes). PM levels are lower at the rural sites at night owing to the nocturnal drainage flows and to the lowering of the mixing layer height below the MSY high. These nocturnal low levels allowed us to estimate the continental background PM levels. At midday, the atmospheric pollutants accumulated in the pre-coastal depression are transported upwards by the breeze, increasing PM levels.Maximum PM10 levels were recorded in summer, and February–March and November, and minimum values in the rest of the year coinciding with the highest frequency of Atlantic advection. PM peak episodes attributed to Saharan dust outbreaks were recorded in summer and February–March. In addition, anticyclonic situations (February–March and November) may impact in elevated rural areas by increasing hourly levels of PM1 up to 75 µg/m3. This scenario induces the stagnation of pollutants in the pre-coastal depression. Solar radiation activates mountain winds, transporting polluted air masses from the valleys to elevated areas resulting in an increase of fine PM levels in areas outside the boundary layer.A significant decrease in PM annual means (40% and 34% for the entire monitoring period, 7 µgPM10/m3 and 5 µgPM2.5/m3) was recorded at MSY between 2002 and 2007. There appears to be no single cause behind these trends. This could partially be ascribed to the varying frequency and intensity of Saharan dust episodes, but also to large-scale meteorological processes or cycles, and/or to local or meso-scale processes such as nearby anthropogenic emission sources.
Article
Economic activities and everyday life may create weekly variations in concentrations of air pollutants in urban settings. The present study contributes to this experience on the example of two typical medium-sized towns in Central Europe, Szeged and Freiburg considering the following air pollutants: NO, NO2, O3, Ox and PM10. Five-year data sets of hourly observations (1997–2001) collected in downtown traffic junctions are analysed. In addition, the effect of the weekly variation on the diurnal course of the air pollutants is also demonstrated, which is especially important when we consider the possible extremes of these traffic related air pollutants. Since the annual variation of the pollutants explains only a minor part of the total variance and, furthermore, the weekly variation behaves rather similarly in the different seasons, the weekly variation of the diurnal peaks is quantified for the whole year. The average annual variations of NO, NO2, O3 and Ox are very similar for both Szeged and Freiburg. Annual levels of NO2 and O3 are moderately higher, while those of PM10 are extremely higher in Szeged, which is reflected in their average weekly and diurnal variations, too. In Freiburg the diurnal variation of PM10 shows a clear daily course with only one wave, compared to that for Szeged with the shape of a double wave. In Szeged, highest percentile values of NO and NO2 occur mostly in the evening, while in Freiburg either in the mourning or in the evening and generally there is very little difference between them. In Szeged, maximum of O3 peak values, while in Freiburg minimum of them are found on weekends.
Article
Summer atmospheric coastal dynamics exert a significant influence on the levels and composition of atmospheric particulate matter (PM) in the North-Eastern Iberian Peninsula. Summer atmospheric scenarios in this region present a high degree of complexity as they are characterised by the absence of synoptic-scale air mass advections, the development of breeze circulations, enhanced photochemistry, local mineral dust re-suspension and the occurrence of African dust outbreaks. Three sampling sites were selected in Barcelona (NE Spain), an urban coastal site surrounded by complex topography. Regional dust modelling (DREAM) and high resolution meteorological modelling (MM5) were used to interpret PM levels and composition at the three sites. The results outline the effect of breeze dynamics and thermal internal boundary layer formation as the main meteorological drivers of the hourly evolution of PM levels. Levels of crustal components, secondary inorganic and carbon species are higher during the night, and only the marine aerosol content is higher during the day. Nitrate levels are higher during the night due to the thermal stability on NH4NO3. Sulphate levels are higher during the night as a consequence of the drainage flows. Lidar measurements and model results signalled the occurrence of two African dust episodes during the study period which mainly affected the free troposphere over Barcelona.
Article
Three years of measurement of PM2.5 with 5-min time resolution was conducted from 2005 to 2007 in urban and rural environments in Beijing to study the seasonal and diurnal variations in PM2.5 concentration. Pronounced seasonal variation was observed in the urban area, with the highest concentrations typically observed in the winter and the lowest concentrations generally found in the summer. In the rural area, the maximum in PM2.5 concentration usually appeared during the spring, followed by a second maximum in the summer, while the minimum generally occurred in the winter. Significant diurnal variations in PM2.5 concentration were observed in both urban and rural areas. In the urban area, the PM2.5 concentration displays a bimodal pattern, with peaks between 7:00 and 8:00 a.m. and between 7:00 and 11:00 p.m. The minimum generally appears around noon. The morning peak is attributed to enhanced anthropogenic activity during rush hours. The decreases of boundary layer height and wind speed in the afternoon companying with increased source activity during the afternoon rush hour result in the highest PM2.5 concentration during evening hours. In the rural area, the PM2.5 concentration shows a unimodal pattern with a significant peak between 5:00 and 11:00 p.m.The seasonal and diurnal variations in PM2.5 concentration in the urban area are mostly dominated by the seasonal and diurnal variability of boundary layer and source emissions. The year-to-year variability of rainfall also has an important influence on the seasonal variation of PM2.5 in the urban area. The seasonal and diurnal wind patterns are more important factors for PM2.5 variation in the rural area. Southerly winds carry pollutants emitted in southern urban areas northward and significantly enhance the PM2.5 concentration level in the rural area.