M. Viana

Spanish National Research Council, Madrid, Madrid, Spain

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Publications (78)203.12 Total impact

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    ABSTRACT: Indoor and outdoor measurements of real-time ultrafine particles (UFP; N10-700 in this study) number concentration and average diameter were collected twice at 39 primary schools located in Barcelona (Spain), with classrooms naturally ventilated under warm weather conditions. Simultaneous outdoor N concentration measurements at schools under different traffic exposures showed the important role of this source, with higher levels by 40% on average at schools near heavy traffic, highlighting thus the increased exposure of children due to urban planning decisions. A well-defined spatial pattern of outdoor UFP levels was observed. Midday increases in outdoor N levels mainly attributed to nucleation processes have been recorded both at high and low temperatures in several of the outdoor school sites (increasing levels by 15%-70%). The variation of these increases also followed a characteristic spatial pattern, pointing at schools' location as a key variable in terms of UFP load owing to the important contribution of traffic emissions. Indoor N concentrations were to some extent explained by outdoor N concentrations during school hours, together with average temperatures, related with natural ventilation. Outdoor midday increases were generally mimicked by indoor N concentrations, especially under warm temperatures. At specific cases, indoor concentrations during midday were 30%-40% higher than outdoor. The time scale of these observations evidenced the possible role of: a) secondary particle formation enhanced by indoor precursors or conditions, maybe related with surface chemistry reactions mediated by O3, and/or b) UFP from cooking activities. Significant indoor N increases were detected after school hours, probably associated with cleaning activities, resulting in indoor N concentrations up to 3 times higher than those in outdoor. A wide variability of indoor/outdoor ratios of N concentrations and mean UFP sizes was detected among schools and measurement periods, which seems to be partly associated with climatic conditions and O3 levels, although further research is required.
    Science of The Total Environment 07/2014; 493C:943-953. · 3.16 Impact Factor
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    ABSTRACT: Particle size distribution patterns of trace elements and metals across three size fractions (<0.25 μm, quasi-ultrafine particles, q-UF; 0.25–2.5 μm, accumulation particles; 2.5–10 μm, coarse particles) were analysed in indoor and outdoor air at 39 primary schools across Barcelona (Spain). Special attention was paid to emission sources in each particle size range. Results evidenced the presence in q-UF particles of high proportions of elements typically found in coarse PM (Ca, Al, Fe, Mn or Na), as well as several potentially health-hazardous metals (Mn, Cu, Sn, V, Pb). Modal shifts (e.g., from accumulation to coarse or q-UF particles) were detected when particles infiltrated indoors, mainly for secondary inorganic aerosols. Our results indicate that the location of schools in heavily trafficked areas increases the abundance of q-UF particles, which infiltrate indoors quite effectively, and thus may impact children exposure to these health-hazardous particles.
    Atmospheric Environment 07/2014; · 3.06 Impact Factor
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    ABSTRACT: This study aims at interpreting the 2001-2012 trends of major air pollutants in Spain, with a major focus on evaluating their relationship with those of the national emission inventories (NEI) and policy actions. Marked downward concentration trends were evidenced for PM10, PM2.5 and CO. Concentrations of NO2 and NOx also declined but in a lesser proportion at rural and traffic sites. At rural sites O3 has been kept constant, whereas it clearly increased at urban and industrial sites. Comparison of the air quality trends and major inflection points with those from NEIs, the National Energy Consumption and the calendar of the implementation of major policy actions allowed us to clearly identify major benefits of European directives on power generation and industrial sources (such as the Large Combustion Plants and the Integrated Pollution Prevention and Control Directives). This, together with a sharp 2007-2008 decrease of coal consumption has probably caused the marked parallel decline of SO2, NOx and for PM2.5 concentrations. Also the effect of the EURO 4 and 5 vehicle emission standards on decreasing emissions of PM and CO from vehicles is noticeable. The smooth decline in NO2-NOx levels is mostly attributed to the low efficiency of EURO 4 and 5 standards in reducing real life urban driving NO2 emissions. The low NOx decrease together with the complexity of the reactions of O3 formation is responsible for the constant O3 concentrations, or even the urban increase. The financial crisis has also contributed to the decrease of the ambient concentration of pollutants; however this caused a major reduction of the primary energy consumption from 2008 to 2009, and not from 2007 to 2008 when ambient air PM and SO2 sharply decreased. The meteorological influence was characterized by a 2008-2012 period favorable to the dispersion of pollutants when compared to the 2001-2007.
    Science of The Total Environment 06/2014; 490C:957-969. · 3.16 Impact Factor
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    ABSTRACT: Children spend a third of their day in the classroom, where air pollution levels may differ substantially from those outdoors due to specific indoor sources. Air pollution exposure assessments based on atmospheric particle mass measured outdoors may therefore have little to do with the daily PM dose received by school children. This study aims to investigate outdoor and indoor sources of PM2.5 measured at 39 primary schools in Barcelona during 2012. On average 47% of indoor PM2.5 measured concentrations was found to be generated indoors due to continuous resuspension of soil particles (13%) and a mixed source (34%) comprising organic (skin flakes, clothes fibers, possible condensation of VOCs) and Ca-rich particles (from chalk and building deterioration). Emissions from seven outdoor sources penetrated easily indoors being responsible for the remaining 53% of measured PM2.5 indoors. Unpaved playgrounds were found to increase mineral contributions in classrooms by 5-6μg/m(3) on average with respect to schools with paved playgrounds. Weekday traffic contributions varied considerably across Barcelona within ranges of 1-14μg/m(3) outdoor and 1-10μg/m(3) indoor. Indoors, traffic contributions were significantly higher (more than twofold) for classrooms with windows oriented directly to the street, rather than to the interior of the block or to playgrounds. This highlights the importance of urban planning in order to reduce children's exposure to traffic emissions.
    Science of The Total Environment 06/2014; 490C:757-765. · 3.16 Impact Factor
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    ABSTRACT: Proximity to road traffic involves higher health risks because of atmospheric pollutants. In addition to outdoor air, indoor air quality contributes to overall exposure. In the framework of the BREATHE study, indoor and outdoor air pollution was assessed in 39 schools in Barcelona. The study quantifies indoor and outdoor air quality during school hours of the BREATHE schools. High levels of fine particles (PM2.5), nitrogen dioxide (NO2), equivalent black carbon (EBC), ultrafine particle (UFP) number concentration and road traffic related trace metals were detected in school playgrounds and indoor environments. PM2.5 almost doubled (factor of 1.7) the usual urban background (UB) levels reported for Barcelona owing to high school-sourced PM2.5 contributions: [1] an indoor-generated source characterised mainly by organic carbon (OC) from organic textile fibres, cooking and other organic emissions, and by calcium and strontium (chalk dust) and; [2] mineral elements from sand-filled playgrounds, detected both indoors and outdoors. The levels of mineral elements are unusually high in PM2.5 because of the breakdown of mineral particles during playground activities. Moreover, anthropogenic PM components (such as OC and arsenic) are dry/wet deposited in this mineral matter. Therefore, PM2.5 cannot be considered a good tracer of traffic emissions in schools despite being influenced by them. On the other hand, outdoor NO2, EBC, UFP, and antimony appear to be good indicators of traffic emissions. The concentrations of NO2 are 1.2 times higher at schools than UB, suggesting the proximity of some schools to road traffic. Indoor levels of these traffic-sourced pollutants are very similar to those detected outdoors, indicating easy penetration of atmospheric pollutants. Spatial variation shows higher levels of EBC, NO2, UFP and, partially, PM2.5 in schools in the centre than in the outskirts of Barcelona, highlighting the influence of traffic emissions. Mean child exposure to pollutants in schools in Barcelona attains intermediate levels between UB and traffic stations.
    Environment International 05/2014; 69C:200-212. · 5.66 Impact Factor
  • Atmospheric Measurement Techniques Discussions. 01/2014; 7(8):8697-8742.
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    Environment International. 01/2014; 69:200–212.
  • Atmospheric Chemistry and Physics 01/2014; 14(9):4459-4472. · 5.51 Impact Factor
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    ABSTRACT: Atmospheric aerosols are emitted by natural and anthropogenic sources. Contributions from natural sources to ambient aerosols vary widely with time (inter-annual and seasonal variability) and as a function of the distance to source regions. This work aims to identify the main natural sources of atmospheric aerosols affecting air quality across Europe. The origin, frequency, magnitude, and spatial and temporal variability of natural events were assessed for the years 2008 and 2009. The main natural sources of atmospheric aerosols identified were African dust, sea spray and wildfires. Primary biological particles were not included in the present work. Volcanic eruptions did not affect air quality significantly in Europe during the study period. The impact of natural episodes on air quality was significant in Southern and Western Europe (Cyprus, Spain, France, UK, Greece, Malta, Italy and Portugal), where they contributed to surpass the PM10 daily and annual limit values. In Central and Northern Europe (Germany, Austria and Latvia) the impact of these events was lower, as it resulted in the exceedance of PM daily but not annual limit values. Contributions from natural sources to mean annual PM10 levels in 2008 and 2009 ranged between 1 and 2μg/m(3) in Italy, France and Portugal, between 1 and 4μg/m(3) in Spain (10μg/m(3) when including the Canary Islands), 5μg/m(3) in UK, between 3 and 8μg/m(3) in Greece, and reached up to 13μg/m(3) in Cyprus. The evaluation of the number of monitoring stations per country reporting natural exceedances of the daily limit value (DLV) is suggested as a potential tool for air quality monitoring networks to detect outliers in the assessment of natural contributions. It is strongly suggested that a reference methodology for the identification and quantification of African dust contributions should be adopted across Europe.
    Science of The Total Environment 12/2013; 472C:825-833. · 3.16 Impact Factor
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    ATMOSPHERIC CHEMISTRY AND PHYSICS 11/2013; 13(21):10767-10768. · 5.30 Impact Factor
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    ATMOSPHERIC CHEMISTRY AND PHYSICS 09/2013; 13:8991-9019. · 5.30 Impact Factor
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    ABSTRACT: The influence of biomass burning (BB) aerosols, whether of regional or local origin, on fine aerosol levels in the Barcelona urban environment (Spain) was investigated. High-time resolved data on light-absorbing aerosols and inorganic tracers in PM2.5 were combined to this end during a dedicated sampling campaign carried out in winter 2011. The evaluation of PM inorganic components and equivalent black carbon evidenced that local-scale BB emissions were not detectable, whereas a source of K, different to vehicular traffic (road dust) and construction/demolition dust re-suspension, was detectable in the urban area. Source apportionment analysis evidenced the contribution from one source traced by S (62% of the source profile) and K (16% of the source profile), which was interpreted as regional-scale transport of secondary aerosols including BB contributions. The S/K ratio for this source (S/K = 4.4) indicated transport of the polluted air masses, as occurs from the rural areas towards the Barcelona urban environment. On average for the study period, the contribution of K-related aerosols from regional BB to PM2.5 levels in the urban environment was estimated as 1.7 μg/m3 as a daily mean, accounting for 8% of the PM2.5 mass during the winter period under study. The contribution from this source to urban aerosols should be lower on the annual scale.
    Atmospheric Environment 06/2013; 72:81–88. · 3.06 Impact Factor
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    ABSTRACT: Globally, coal is second to oil the biggest energy source. Coal combustion is utilized mainly for power generation, in industry and to a lesser extent also for home heating in small stoves and boilers. The latter is known to be a major burden for air quality. The present paper describes the results of a PM and PAH source apportionment casestudy, carried out in Krakow (Poland), where coal is still widely used for residential heating. In the service and residential sectors Poland alone consumes much more coal than all the old EU member states together consume in these sectors. Krakow is Poland’s second largest city and one of the most polluted cities with regards to particulate matter (PM) and associated compounds, such as benzo(a)pyrene (B(a)P. The present study was designed to apportion various coal combustion sources in comparison with other main sources for these pollutants, and the obtained results are expected to be useful for planning abatement strategies in all areas of the world, where coal combustion in small appliances is significant. Outdoor and indoor PM10 collected in Krakow, during typical winter pollution events, was chemically analyzed together with PM emissions from 20 major sources and the obtained data was subjected to multivariate receptor modelling. 52 individual compounds were included comprising elementary and organic carbon (EC/OC), major anions and cations, trace elements, polyaromatic hydrocarbons and azaarenes. The source apportionment was accomplished by seven different multivariate receptormodels: Chemical mass balance modelling (CMB), constrained positive matrix factorization (CMF), Edge analysis (UNMIX), positive matrix factorization (PMF), PCA coupled with multi-linear regression analysis (PCA-MLRA), Self organizing Maps (SOM), and cluster Analysis (CA). The results of the source apportionment of PM10 and benzo(a)pyrene pollution from coal combustion in Krakow, Poland has been described elsewhere with focus on the pollution problem (Junninen et al., 2008). In the present report complete detailed information is given on the receptor modelling exercise, and all underpinning data. All material is available on an electronic form (bo.larsen@ec.europa.eu).
    EUR 23621 EN 05/2013; European Communities., ISBN: 978-92-79-10938-6
  • Atmospheric Chemistry and Physics 01/2013; 13(12):32849-32883. · 4.88 Impact Factor
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    ABSTRACT: The identification of sources is one of the prerequisites for the implementation of the Air Quality Directive (AQD). It provides scientific support to the development and periodic revision of air quality plans and short term action plans and to the quantification of categories with special status like long range transport, natural sources and winter road salting and sanding. The suitability of receptor models (RM) for the apportionment of pollutant sources in the implementa-tion of the AQD is testified by the amount of published studies in 2005 and 2010 in correspondence with the entry into force of new provisions for PM10 and PM2,5, respectively. In recent years, Member States were requested to provide official estimations of source contribution to the Commission like the quantification of natural sources in 2006 and PM10 time extension reports in 2009 (Fragkou et al., 2011). These experiences have shown that al-though this kind of methodology is used by about 60% of the European experts involved in source apportion-ment there is a considerable variability in the methodo-logical approaches and adopted tools. Furthermore, there are critical steps that require strict quality assurance standards and skilled practitioners (e.g. identification of the appropriate number of sources). In order to foster harmonization in this field, the JRC has promoted a number of interconnected initiatives linked to FAIRMODE. One of those was to set up a group of experts with skills in different areas to assess RM methodologies and propose common criteria and procedures for source apportionment studies. The infor-mation collected was summarized in a document which is intended to serve as a basis for a common Receptor Model Technical Protocol (RMTP). The RMTP is addressed to different kinds of us-ers: Policy makers and managers interested in the output of RMs for development of mitigation measures, air quality experts and scientists unfamiliar with these tech-niques, and RM practitioners involved in the model ex-ecution and interpretation of results. In order to address such heterogeneous readership the document was designed to be accessible at different levels. The RMTP is organized in three sections: • an introduction to present the methodology to the unskilled reader, illustrating its capabilities and recom-mending when and how to use it. • a core section concerning the most common RM methodologies for source apportionment with in-depth analysis boxes for more experienced readers. The section is structured in 13 chapters following, as a check list, the logical steps to accomplish a source apportionment study. The first chapters deal with preliminary activities like the evaluation of the study area, collection of exist-ing information and experimental design. In the follow-ing chapters data collection and data treatment are dis-cussed. The section includes also chapters regarding spe-cific aspects of widely used methodologies like CMB, Factor Analysis, and PMF. The evaluation of test per-formance and reporting are discussed in the last part of this section. • the third section of the document was conceived to give an insight on the capabilities and the possible future trends in RM methodology. It consists of four chapters dealing with advanced, innovative techniques for which ready- to-use tools are already available or under development: trajectory analysis combined with RM, constrained and expanded models, AMS data processing, and the aethalometer model. The document includes a number of annexes to provide additional and practical information on specific topics, and examples. References Fragkou et al., 2011 http://www.harmo.org/Conferences/Proceedings/_Kos/publishedSections/H14-290.pdf
    European Aerosol Conference 2012; 09/2012
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    ABSTRACT: During the 1999–2008 period a statistically significant downward trend in the concentrations of SO2, NOx, CO and PM2.5 was determined at most of the urban and urban-background monitoring sites in the Madrid metropolitan area. However, no statistically significant trend was detected in PM10 concentrations at any urban and rural site and in NO2 concentrations at the urban sites. The reduction in the annual coal consumption and in the number of gasoline vehicles and the use of particle filters for diesel engines in this area, have contributed to this reduction of SO2, CO and fine PM concentrations, but the increase of the diesel fleet is probably the cause of an increase of the NO2/NOx ratio and the lack of a decreasing trend of NO2 concentrations. Chemical characterisation and receptor modelling analysis results showed that mean contributions to PM10 and PM2.5 levels attributed to anthropogenic sources throughout the 1999–2008 period, decreased at the Madrid urban areas mainly by reductions in their carbonaceous and SO42− contents. However, the contribution of mineral dust to PM10 bulk levels did not significantly decrease at the urban sites. Thus, strategies aimed at reducing levels of PM10 and PM2.5 concentrations focussing mainly on road traffic and coal consumption, can be insufficient to reduce the number of days exceeding the PM10 Daily Limit Value (50 μg m−3) at some metropolitan areas, such as Madrid, where crustal content due to anthropogenic activities and natural phenomena is elevated even when the African dust contribution during episodic days is excluded. Changes in the structure of the metropolitan area such as the increase of the Madrid car fleet and of its proportion of diesel vehicles, could also contribute to keep or increase the concentration of other pollutants (NO2) which resulted in increases of the NO3− contribution to PM10 and PM2.5 levels.
    Atmospheric Environment 09/2012; 57:175–185. · 3.06 Impact Factor
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    ABSTRACT: The adverse consequences of particulate matter (PM) on human health have been well documented. Recently, special attention has been given to mineral dust particles, which may be a serious health threat. The main global source of atmospheric mineral dust is the Sahara desert, which produces about half of the annual mineral dust. Sahara dust transport can lead to PM levels that substantially exceed the established limit values. A review was undertaken using the ISI web of knowledge database with the objective to identify all studies presenting results on the potential health impact from Sahara dust particles. The review of the literature shows that the association of fine particles, PM₂.₅, with total or cause-specific daily mortality is not significant during Saharan dust intrusions. However, regarding coarser fractions PM₁₀ and PM₂.₅₋₁₀ an explicit answer cannot be given. Some of the published studies state that they increase mortality during Sahara dust days while other studies find no association between mortality and PM₁₀ or PM₂.₅₋₁₀. The main conclusion of this review is that health impact of Saharan dust outbreaks needs to be further explored. Considering the diverse outcomes for PM₁₀ and PM₂.₅₋₁₀, future studies should focus on the chemical characterization and potential toxicity of coarse particles transported from Sahara desert mixed or not with anthropogenic pollutants. The results of this review may be considered to establish the objectives and strategies of a new European directive on ambient air quality. An implication for public policy in Europe is that to protect public health, anthropogenic sources of particulate pollution need to be more rigorously controlled in areas highly impacted by the Sahara dust.
    Environment international 07/2012; 47:107-14. · 6.25 Impact Factor
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    ABSTRACT: Mean annual biomass burning contributions to the bulk particulate matter (PM(X)) load were quantified in a southern-European urban environment (Barcelona, Spain) with special attention to typical Mediterranean winter and summer conditions. In spite of the complexity of the local air pollution cocktail and the expected low contribution of biomass burning emissions to PM levels in Southern Europe, the impact of these emissions was detected at an urban background site by means of tracers such as levoglucosan, K(+) and organic carbon (OC). The significant correlation between levoglucosan and OC (r(2)=0.77) and K(+) (r(2)=0.65), as well as a marked day/night variability of the levoglucosan levels and levoglucosan/OC ratios was indicative of the contribution from regional scale biomass burning emissions during night-time transported by land breezes. In addition, on specific days (21-22 March), the contribution from long-range transported biomass burning aerosols was detected. Quantification of the contribution of biomass burning aerosols to PM levels on an annual basis was possible by means of the Multilinear Engine (ME). Biomass burning emissions accounted for 3% of PM(10) and PM(2.5) (annual mean), while this percentage increased up to 5% of PM(1). During the winter period, regional-scale biomass burning emissions (agricultural waste burning) were estimated to contribute with 7±4% of PM(2.5) aerosols during night-time (period when emissions were clearly detected). Long-range transported biomass burning aerosols (possibly from forest fires and/or agricultural waste burning) accounted for 5±2% of PM(2.5) during specific episodes. Annually, biomass burning emissions accounted for 19%-21% of OC levels in PM(10), PM(2.5) and PM(1). The contribution of this source to K(+) ranged between 48% for PM(10) and 97% for PM(1) (annual mean). Results for K(+) from biomass burning evidenced that this tracer is mostly emitted in the fine fraction, and thus coarse K(+) could not be taken as an appropriate tracer of biomass burning.
    Science of The Total Environment 05/2012; 427-428:175-90. · 3.16 Impact Factor
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    ABSTRACT: Abstract. The lack of standard reference materials for calibrating, troubleshooting and intercomparing techniques that measure the composition of black carbon, commonly referred to as soot, has been a major obstacle that hinders improved understanding of how climate and health is impacted by this ubiquitous component of the atmosphere. A different approach is offered here as a means of constructing precisely controlled material with fractions of organic carbon (OC) on the surface of elemental carbon (EC) whose structure reflects that of the combustion produced particles found in the atmosphere. The proposed soot reference material (SRM) uses EC as a basis substrate for surface coatings of organic compounds that are representative of the main classes of organics identified in the coverage of soot produced by fossil fuel burning. A number of methods are used to demonstrate the quality and stability of the reference EC and SRM. Comparison of the nominal fraction of OC deposited on the EC substrate with the fraction measured with thermal/optical analysis (TOA) shows excellent agreement. Application of this type of reference material for evaluating the different methods of carbon analysis may help resolve differences that currently exist between comparable measurement techniques when trying to separate OC and EC from ambient samples.
    Atmos. Meas. Tech. Discus. 01/2012; 5:2315-2362.

Publication Stats

2k Citations
203.12 Total Impact Points

Institutions

  • 2006–2010
    • Spanish National Research Council
      • Institute of Environmental Assessment and Water Research
      Madrid, Madrid, Spain
  • 2009
    • University of Aberdeen
      • School of Biological Sciences
      Aberdeen, SCT, United Kingdom
  • 2008
    • Instituto de Salud Carlos III
      Madrid, Madrid, Spain
  • 2002–2008
    • Institute Of Earth Sciences Jaume Almera
      Barcino, Catalonia, Spain