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The importance of high vehicle power for passenger car emissions
... Kousoulidou et al. (2013) for example use 6 vehicles over a two-week period to study emissions factors compared to a remote sensing study which can study 20k or more vehicles per week. Whilst work is being done to improve the number of vehicles studied using PEMS with O'Driscoll et al. (2016) M a n u s c r i p t giving results that differ to what would be expected in a laboratory (Smit and Bluett 2011), especially in the field of high emitting vehicles where multiple measurements are possible (Carslaw et al. 2013). As remote sensing studies survey the emission performance of tens of thousands of vehicles, unlike PEMS or laboratory studies, their results can be used to contrast Real Driving Environments from different marques and models without fear of the results being distorted by a faulty vehicle, test or bad batch of fuel. ...
... There is some evidence that the RSD4600 underestimates the acceleration at the most extreme values however those levels of acceleration are not typical of real world driving and are still largely within the error of the instrumentation. The finding is A c c e p t e d M a n u s c r i p t that the speed and acceleration measured by the RSD4600 is validated and therefore the calculated VSP are considered reliable in such studies as Carslaw et al. (2013). ...
... The speed and acceleration measurements were validated using a state of the art GPS system with the RSD4600 performing strongly. As the speed and acceleration module performed well studies using the speed and this element of the RSD4600 to calculate vehicle specific power as a diagnostic tool are validated in other works such as Carslaw et al. (2013). The results are limited to vehicles operating in the lowest three gears however for urban driving these results represent the majority of operating conditions. ...
Implications:
Synchronized remote sensing measurements of NO were taken using two different remote sensing devices in an off-road study. It was found that the measurements taken by both instruments were well correlated. Fractional NO2 measurements from a prior study, measurable on only one device, were used to create new NOx emission factors for the device that could not be measured by the second device. These estimates were validated against direct measurement of total NOx emission factors and shown to be an improvement on previous methodologies. Validation of vehicle specific power was performed with good correlation observed.
... Remote sensing devices (RSDs), however, can un-intrusively take a snap-shot sample of fuel-specific emission rates (grams.kg -1 ) from a large number of vehicles in a single day (Beaton et al., 1995, Huang et al., 2018, proving cost-effective for fleet emission monitoring (Carslaw et al., 2011, Carslaw et al., 2013, Chen and Borken-Kleefeld, 2016, Grange et al., 2019 and high-emitter detection (Borken-Kleefeld, 2013, Pujadas et al., 2017, Huang et al., 2019. Nonetheless, some research contends that the validity of a single RSD record in reflecting the actual emission performance of a passing vehicle requires assessment (Qiu and Borken-Kleefeld, 2022). ...
... Vehicle Specific Power (VSP) value is a metric informing the power demands on the engine during driving (Jiménez-Palacios, 1999). The VSP value is often considered to be associated with NOx emissions (Carslaw et al., 2013, Yang et al., 2016. It is used to identify whether vehicles are at high load (where high emissions are expected) or at very low load (where fuel injection is disabled and plume sizes insufficient for valid remote sensing measurements). ...
Identifying and managing high-emitters among heavy-duty diesel vehicles is a key to mitigating urban air pollution, as a small number of such vehicles could contribute a significant amount of total transport emissions. On-board monitoring (OBM) systems can directly monitor the real-time emission performance of heavy-duty vehicles on road and have become part of the future emissions compliance framework. The challenge, however, lies in the frequent unavailability of OBM data, affecting the effective screening of high-emitting vehicles. This work proposes to bridge the gap by integrating OBM data with remote sensing data to create a comprehensive monitoring system. OBM data is used to characterize the detailed real-world NOx emission performance of both normally-behaving vehicles and high-emitters at various vehicle operating conditions. Remote sensing data is employed to screen out candidate high-emitting vehicles based on thresholds determined by OBM data. Finally, the dynamic NOx emission reduction potential across all roads is mapped by combining the trajectory data for each vehicle with the emission data. A case study in Chengdu, China, utilizing emission and traffic data from heavy-duty vehicles for transporting construction waste (a.k.a. slag trucks), reveals the national threshold for identifying high-emitters via remote sensing might be too lenient, particularly in the medium speed range. An emission reduction of 18.8% in the China V slag truck fleet could be achieved by implementing this novel method in practice in Chengdu. This approach establishes a reliable and ongoing scheme for pinpointing high-emitters through multi-source data, which allows local authorities to develop more robust and targeted strategies to mitigate urban air pollution from heavy-duty diesel vehicles.
... Zurich data have additional entries from campaigns using the HEAT-EDAR instrument. All instruments have been discussed extensively in previous studies (Bishop et al., 1996;Borken-Kleefeld & Chen, 2015; D. C. Carslaw et al., 2013;Chen & Borken-Kleefeld, 2014;Ropkins et al., 2017;Rushton et al., 2018). The measurement devices were regularly calibrated against known gas concentrations. ...
... Higher engine loads are known to increase the NOx emission rate of diesel cars (D. C. Carslaw et al., 2013). Fig. 4 presents NOx emissions as a function of vehicle class, emission technology, and instantaneous VSP, all while selecting records taken in the ambient temperature range between 20 • C and 30 • C. ...
Are emissions from passenger and diesel cars affected by increasing altitude?
... From this time, for vehicle emissions analysis it is often the higher level quantifications are of most interest. The conditions under which vehicles tend to emit high levels of emissions are of interest because of the potential to impact atmospheric concentrations of key pollutants (Carslaw et al., 2013); (Maia, 2013). In this paper a novel approach will be followed. ...
... It does, however, have a higher octane value which partially offsets this decrease in energy content. Different ethanol blend (E5, E27, E75, E85) properties are taken into consideration, in terms of unburned hydrocarbon density, fuel density, and fuel consumption carbon balance formula ( (Vilar et al., 2003) (Carslaw et al., 2013). The Program to Control Air Pollution from Motor Vehicles (PROCONVE) by the Brazilian National Council of the Environment (known as CONAMA) have been established air pollutant emission limits for motor vehicles with Diesel cycle engines (i.e. ...
On-road measurement of vehicle tailpipe emissions, analyzing the data and developing a model, is very important to identify and recommend improved design and management approaches for the transport sector. A light-duty vehicle, the flex-fuel Nissan Versa equipped with a 1.6 liter engine and manual transmission was monitored in real operation. The on-board monitoring equipment consisted of a five-gas analyzer for CO, HC(CH4), NOx, CO2 and SO2 in addition to dry systems, with sample lines directly connected to the tailpipe, and an on-board diagnostics (OBD II) connector, GPS, including other additional parameters monitoring (i.e. data logger with embedded microcontrollers). The operating parameters registered in this vehicle were: vehicle speed, engine speed, fuel consumption, angle position of the throttle valve, cooling water, oil and exhaust gas temperatures. The measurements were performed using gasoline with 27%, and 100% ethanol blends (E27 and E100 respectively, where E27 is used in emission certification). The vehicle-experiment (driving pattern) was realized in an urban route in the Fortaleza City, Brazil, under typical traffic conditions. The analysis indicates that the average emission rates (kg/h) for CO are more than a factor of 10 higher to NO idling emissions. AVL CRUISE integrated with AVL BOOST software were used to model the vehicle and the flex-fuel engine engine in both certification driving cycles and real operation ones. Real operation data is used to validate the model.
... Readers are referred to Cade and Noon (2003) Koenker (2005), and Hao and Naiman (2007) for further details on QRM; and to Baur et al. (2004), Munir et al. (2012) for the applicability of QRM to ground-level O 3 concentrations. QRM has also been used by Carslaw et al. (2013) on emission data for the first time in order to explain the emission characteristics of petrol and diesel cars. Carslaw et al. (2013) explained the advantage of using this method in comparison to other regression methods which consider the mean response only. ...
... QRM has also been used by Carslaw et al. (2013) on emission data for the first time in order to explain the emission characteristics of petrol and diesel cars. Carslaw et al. (2013) explained the advantage of using this method in comparison to other regression methods which consider the mean response only. However, Ul-Saufie et al. (2012) have used QRM for modelling PM 10 concentration and compared it performance with MLRM. ...
The ability to accurately model and predict the ambient concentration of Particulate Matter (PM) is essential for effective air quality management and policies development. Various statistical approaches exist for modelling air pollutant levels. In this paper, several approaches including linear, non-linear, and machine learning methods are evaluated for the prediction of urban PM10 concentrations in the City of Makkah, Saudi Arabia. The models employed are Multiple Linear Regression Model (MLRM), Quantile Regression Model (QRM), Generalised Additive Model (GAM), and Boosted Regression Trees1-way (BRT1) and 2-way (BRT2). Several meteorological parameters and chemical species measured during 2012 are used as covariates in the models. Various statistical metrics, including the Mean Bias Error (MBE), Mean Absolute Error (MAE), Root Mean Squared Error (RMSE), the fraction of prediction within a Factor of Two (FACT2), correlation coefficient (R), and Index of Agreement (IA) are calculated to compare the predictive performance of the models. Results show that both MLRM and QRM captured the mean PM10 levels. However, QRM topped the other models in capturing the variations in PM10 concentrations. Based on the values of error indices, QRM showed better performance in predicting hourly PM10 concentrations. Superiority over the other models is explained by the ability of QRM to model the contribution of covariates at different quantiles of the modelled variable (here PM10). In this way QRM provides a better approximation procedure compared to the other modelling approaches, which consider a single central tendency response to a set of independent variables. Numerous recent studies have used these modelling approaches, however this is the first study that compares their performance for predicting PM10 concentrations.
... The emission factors are based on European standard driving cycles, which might not reflect local driving situations accurately, see e.g. Carslaw et al. (2011Carslaw et al. ( , 2013. Models for cold start emissions are additionally provided which can be used to assess specific local developments, but more research is required to calculate local emissions more accurately. ...
... The emission factors are based on European standard driving cycles, which might not reflect local driving situations accurately, see e.g. Carslaw et al. (2011Carslaw et al. ( , 2013. Models for cold start emissions are additionally provided which can be used to assess specific local developments, but more research is required to calculate local emissions more accurately. ...
This report is a review of recent developments in economic appraisal in the transport sector and the use of appraisal in the decision making process in England. It is the annex to a report in which appraisal practice in England, and its development, is compared with that in Germany, Netherlands, Sweden, USA, Australia (NSW), and New Zealand as exemplars of good practice and varied institutional arrangements.
... Table 3 shows how, in an established hydrogen economy, the launch of zero-carbon hydrogen vehicles can lower average CO 2 emissions in the transportation sector. The data are based on the average emissions of 140 g CO 2 /km driven in 2008 [14]. ...
This edited book, which is a piece of artwork prepared TUBA-Energy Working Group, brings a holistic approach to energy and covers all aspects of it, ranging from its history and importance to fundamental thermodynamic concepts and from the dimensions of energy systems to the role of innovation in these systems. The topics covered in the book are extensive and include basic thermodynamic concepts and methods, traditional fossil fuels, renewable energy resources, nuclear energy, biofuels, and alternative fuels, hydrogen energy, waste-to-energy, energy conservation and efficiency, energy storage, energy materials, smart grids, energy policies and strategies, economics and effectiveness of energy systems, energy- environment-sustainability as well as energy innovation.
... Despite the fact that vans have contributed a significant proportion to total UK's CO 2 and NO X emissions, the majority of existing studies focus on the passenger car emissions (Carslaw et al., 2013;Chen and Borken-Kleefeld, 2016;Pavlovic et al., 2016). Considering many studies have already demonstrated the gap between laboratory and real-driving emissions for passenger cars (Carslaw et al., 2011;O'Driscoll et al., 2018;Tietge et al., 2019), it is expected there is a significant divergence for vans as well. ...
Refrigerated vans used for home deliveries are attracting attention as online grocery shopping in the UK is expanding rapidly and contributes to the increasing greenhouse gas (CO2) and nitrogen oxides (NOX) emissions. These vans are typically 3.5-tonne gross weight vehicles equipped with temperature-controlled units called Transport Refrigeration Units (TRUs), which are usually powered off the vehicles' engine. It is obvious that vehicles with added weight of TRUs consume more fuel and emit more NOX, let alone the vehicles' diesel engines are also powering the refrigeration units, which further elevates the emissions.
This research uses an instantaneous vehicle emission model PHEM (version 13.0.3.21) to simulate the real-world emissions from refrigerated vans. A validation of PHEM is included using data from laboratory (chassis dynamometer) tests over a realistic driving profile (the London Drive Cycle), to assess its ability to quantify the impact of changing vehicle weights and carrying loads. The impact of the TRU weight, greater frontal area increasing aerodynamic drag and refrigeration load on van emissions is then estimated by PHEM. The influence of ambient temperature, cargo weight and driving condition on CO2 and NOX emission from refrigerated van are also assessed.
Overall CO2 emissions of vans with TRUs are found to be 15% higher than standard vehicles, with NOX emissions estimated to be elevated by 18%. This confirms the need to take into account the impact of additional engine load when predicting van emissions in this and other sectors such as ambulances which are relatively heavy, high powered vehicles. Moreover, findings of the impact of TRUs on fuel consumptions can be used to optimize fuel-saving strategies for refrigerated vans and test cases for alternative low- or zero-emission technologies, to support progress to a sustainable net-zero society.
... 17,22,23 Particularly, Carslaw et al. found a clear increase of the NO x emission rate with increasing VSP. 13 In the NEDC type-approval driving cycle in Europe, VSP ranges from 3 to 22 kW/ton, which is consist of normal urban driving and extra-urban driving cycles. To assess impacts of vehicle power on the sample size determination, in Figure 4a, we present minimum sample size under various VSP bins and various accuracy performance metrics, i.e., 70, 80, and 90% certainty ratio of estimation, A n . ...
The power of remote vehicle emission sensing stems from the big sample size obtained and its related statistical representativeness for the measured emission rates. But how many records are needed for a representative measurement and when does the information gain per record become insignificant? We use Monte Carlo simulations to determine the relationship between the sample size and the accuracy of the sample mean and variance. We take the example of NO emissions from diesel cars measured by remote emission monitors between 2011 and 2018 at various locations in Europe. We find that no more than 200 remote sensing records are sufficient to approximate the mean emission rate for Euro 4, 5 and 6a,b diesel cars with 80% certainty within a ±1 g NO per kg fuel tolerance margin (~±50 mg NO per km). Between 300 and 800 remote sensing records are needed to approximate also the variance of the mean NO emission rates for those diesel car technologies. This translates to only 2 and up to 9 measurement days respectively to characterize the means and their variance for a car fleet typical in Europe.
... The choice of appropriate opmode distributions for emissions is based on second-by-second vehicle speed trajectory, also known as the drive cycles. Drive cycles allow a more accurate estimation of energy consumption by representing driving behavior and acceleration rates (Carslaw et al., 2013). Fujita et al. (2012) compared different emission modeling software with field measurements and found that the estimation of emissions in MOVES was highly sensitive to opmode selection. ...
This study presents the development of operating mode (opmode) distributions derived from local drive cycle construction methods developed based on real-world GPS data collection, and their impacts on average-speed emission factors (EFs). A data collection campaign was conducted between March and July 2018 whereby 82 research participants were recruited to record daily driving behaviors in the Greater Toronto and Hamilton Area (GTHA) for a period of one week. A drive cycle construction methodology was employed to build representative drive cycles based on micro-trips. The constructed drive cycles were compared with the interpolated drive cycles derived from the default database of the USEPA MOVES model. The results indicate that the MOVES default opmode distributions lead to higher average-speed EFs than the ones derived from local data. The difference between two drive cycle construction methods was also evaluated by comparing the variability in opmode distributions and the resulting average speed EFs. We observed that EFs were similar within each speed category, and the variation in cumulative opmode distributions was highest for an average speed of 40 mph. Moreover, a Monte Carlo Simulation was conducted to generate EF distributions based on local opmodes, further illustrating that local drive cycles generated significantly lower emission estimates than those based on the default database of MOVES. Finally, the minimum number of GPS data points required to develop a local opmode database with adequate variability was determined, illustrating that 4400–19,300 s were needed to generate robust distributions for different speed categories and road types.
... Under these conditions, the flame temperature is high and there is excess oxygen during the flame diffusion process in diesel engines [50,19]. Therefore, it is usual for diesel engines to generate more NO x in the motorway and rural sections because higher engine loads are required [51,27]. Under these conditions, an increase in fuel injection and a reduction of the airfuel equivalence ratio occurs [50,52]. ...
In real-world driving, most Euro 5 and 6 diesel passenger cars exceed the nitrogen oxides (NOx) emission limits of type approval procedure. The emission factors of the fleet of Euro 6 vehicles show high variability, irrespective of the NOx control technology. This comprehensive study focused on the events of high instantaneous NOx emissions produced under real driving, to assess their impact on emission factors. Additionally, the relationships of these events with different parameters measured using portable emissions measurement system (PEMS) were determined. Three Euro 6b diesel passenger cars with exhaust gas recirculation (EGR), lean-burn NOx trap (LNT) and selective catalytic reduction (SCR) were tested based on the real driving emissions (RDE) regulation.
The results show that high instantaneous NOx emissions represent a large amount of total NOx emissions, although they are produced in a small percentage of driving time. A theoretical constraint of these high NOx emissions could reduce emission factors by 30–82%. The emission of high instantaneous NOx emissions are related to characteristic speed modes of urban, rural and motorway sections, and are primarily produced in a narrow engine speed range of approximately 700 rpm. In general, the probability of producing high instantaneous NOx emissions increases as the engine speed, the exhaust gas temperature or the vehicle speed is increased. Finally, regarding driving severity, speed per positive acceleration (v⋅a+) observations above the maximum values of the new European driving cycle (NEDC) and the world-harmonized light-duty vehicle test cycle (WLTC), have a strong probability to yield high instantaneous NOx emissions. These findings could be useful in the design of low emission policies, optimization of NOx control strategies, and the improvement of micro/meso emission models.
... Between 2000 and 2015, new passenger cars in Europe grew from an average of 1300 kg to an average of 1400 kg in mass, this additional 100 kg load causing an increase from 0.3 to 0.5 L/100 km in fuel consumption or 7.5-12.5 gCO 2 /km in emission, respectively (Fontaras et al., 2017). In this context it is remarkable that while maximum engine power of petrol cars remained almost constant since 1990 among new registrations, it grew from 67 to 100 kW between 1995 and 2010 in diesel cars (Carslaw et al., 2013), also reflecting their size growth in this period. Knittel (2012) provided the most detailed investigation of the effects of light duty vehicles power and weight increase on fuel consumption in the USA, an analysis missing so far for the European market. ...
A comprehensive overview is provided evaluating direct real-world CO2 emissions of both diesel and petrol cars newly registered in Europe between 1995 and 2015. Before 2011, European diesel cars emitted less CO2 per kilometre than petrol cars, but since then there is no appreciable difference in per-km CO2 emissions between diesel and petrol cars. Real-world CO2 emissions of diesel cars have not declined appreciably since 2001, while the CO2 emissions of petrol cars have been stagnant since 2012. When adding black carbon related CO2-equivalents, such as from diesel cars without particulate filters, diesel cars were discovered to have had much higher climate relevant emissions until the year 2001 when compared to petrol cars. From 2001 to 2015 CO2-equivalent emissions from new diesel cars and petrol cars were hardly distinguishable. Lifetime use phase CO2-equivalent emissions of all European passenger vehicles were modelled for 1995–2015 based on three scenarios: the historic case, another scenario freezing percentages of diesel cars at the low levels from the early 1990s (thus avoiding the observed “boom” in new diesel registrations), and an advanced mitigation scenario based on high proportions of petrol hybrid cars and cars burning gaseous fuels. The difference in CO2-equivalent emissions between the historical case and the scenario avoiding the diesel car boom is only 0.3%. The advanced mitigation scenario would have been able to achieve a 3.4% reduction in total CO2-equivalent emissions over the same time frame. The European diesel car boom appears to have been ineffective at reducing climate-warming emissions from the European transport sector.
... The remote sensing data has several appealing characteristics [3]. Firstly, it is possible to sample large numbers of vehicles that make up a diverse car population. ...
More and more researchers are using remote sensing technology to measure real-world, on-road automobile emissions of nitric oxide (NO), one of the most important and frequently studied pollutants. Partnered with the National Institute of Water and Atmospheric Research (NIWA) in New Zealand, we aim to establish a robust NO emission factor prediction model using remote sensing data to forecast future emissions. This model can be extremely useful to local transport authorities for monitoring urban pollution levels and validating the effectiveness of existing traffic control policies. We have conducted this research using real-world data that were collected over a 10-year span between 2005 and 2015. The experimental results have shown that the vehicle emission patterns are continuously changing and the relevance of remote sensing data for future predictions decays as they get older.
We propose a 3-step machine learning approach to establish this model. Most notably we use quantile regression forest (a variation of random forest) as the base algorithm and use random forest's variable importance measure to validate and interpret the features. The model yields error rates that compare favourably to linear model based recursive partitioning and the original random forest model.
... Table 3 shows how, in an established hydrogen economy, the launch of zero-carbon hydrogen vehicles can lower average CO 2 emissions in the transportation sector. The data are based on the average emissions of 140 g CO 2 /km driven in 2008 [14]. ...
As we face global energy challenges, it becomes essential to focus on novel and innovative technologies that increase the diversity of energy resources. This requires significant innovation in energy production, conversion, delivery, storage, and end use. Hydrogen energy represents a great potential solution to meet global energy demand. Hydrogen energy could possibly represent a world where our energy-related emissions and other environmental damage issues are eliminated or minimized and where our demand for affordable, efficient, reliable, and clean energy is met. To fully understand "the hydrogen energy," it is necessary to comprehend all aspects of hydrogen from its characteristic properties to difference from existing fuels. Therefore, this chapter provides information on characteristics of hydrogen, and its comparison to other fuels and energy sources.
... A useful indicator of engine load is vehicle specific power (VSP), which is a function of speed, acceleration, and road grade (Jiménez-Palacios, 1999). Relationships between VSP and rates of fuel use and emissions have been evaluated for gasoline vehicles (e.g., Carslaw et al., 2013;Frey et al., 2010;Yao et al., 2010). Such rates are usually lowest for engine idling and increase monotonically with positive VSP. ...
Implications:
Reported comparisons of flex fuel vehicle (FFV) tailpipe emission rates for E85 versus gasoline have been inconsistent. To date, this is the most comprehensive evaluation of available and new data. The large range of inter-vehicle variability illustrates why prior studies based on small sample sizes led to apparently contradictory findings. E85 leads to significant reductions in tailpipe nitrogen oxide (NOx) and carbon monoxide (CO) emission rates compared with gasoline, indicating a potential benefit for ozone air quality management in NOx-limited areas. The comparison of FFV tailpipe emissions between E85 and gasoline is sensitive to power demand and driving cycles.
... For example, a Euro 3 car introduced in 2000 will be ~5-6 years old at the end of the Euro 3 period. Analysis of vehicle emission remote-sensing data has shown that vehicle ageing tends to decrease the NO 2 / NO x ratio of diesel passenger cars (and probably other types of vehicles fitted with a DOC) 16,33 . All of these influences, combined with other local effects, contribute to the overall pattern seen in Fig. 1. ...
Many European countries do not meet legal air quality standards for ambient nitrogen dioxide (NO2) near roads; a problem that has been forecasted to persist to 2030. Although European air quality standards regulate NO2 concentrations, emissions standards for new vehicles instead set limits for NOx—the combination of nitric oxide (NO) and NO2. From around 1990 onwards, the total emissions of NOx declined significantly in Europe, but roadside concentrations of NO2—a regulated species—declined much less than expected. This discrepancy has been attributed largely to the increasing usage of diesel vehicles in Europe and more directly emitted tailpipe NO2. Here we apply a data-filtering technique to 130 million hourly measurements of NOx, NO2 and ozone (O3) from roadside monitoring stations across 61 urban areas in Europe over the period 1990–2015 to estimate the continent-wide trends of directly emitted NO2. We find that the ratio of NO2 to NOx emissions increased from 1995 to around 2010 but has since stabilized at a level that is substantially lower than is assumed in some key emissions inventories. The proportion of NOx now being emitted directly from road transport as NO2 is up to a factor of two smaller than the estimates used in policy projections. We therefore conclude that there may be a faster attainment of roadside NO2 air quality standards across Europe than is currently expected.
... They also indicated that it is necessary to determine the amount of primary NO2 and identify systematic differences among emissions of the different dominant brands in European fleets. Along the same lines highlight the work done by the King's College London (Carslaw et al, 2011;Carslaw et al, 2013a, Carslaw et al, 2013b. The campaign was conducted from 2007 to 2010 (7 campaigns at different points) with a total of more than 80,000 valid records, the high values of the emission of NOx/CO2 for modern vehicles (Euro 4/5) were also detected contrary to expected emissions due to stricter emissions standards. ...
... Traffic emissions contribute significantly to air pollution (Beevers et al., 2012;Carslaw et al., 2013;May et al., 2014). In order to better analyse traffic emissions and their impact on air quality, it is necessary to understand the fuel type and pollutant contribution from different vehicles. ...
The multilinear engine (ME-2) factorization tool is being
widely used following the recent development of the Source Finder (SoFi)
interface at the Paul Scherrer Institute. However, the success of this tool,
when using the a value approach, largely depends on the inputs (i.e. target
profiles) applied as well as the experience of the user. A strategy to
explore the solution space is proposed, in which the solution that best
describes the organic aerosol (OA) sources is determined according to the
systematic application of predefined statistical tests. This includes
trilinear regression, which proves to be a useful tool for comparing different
ME-2 solutions. Aerosol Chemical Speciation Monitor (ACSM) measurements were
carried out at the urban background site of North Kensington, London from
March to December 2013, where for the first time the behaviour of OA sources
and their possible environmental implications were studied using an ACSM.
Five OA sources were identified: biomass burning OA (BBOA), hydrocarbon-like
OA (HOA), cooking OA (COA), semivolatile oxygenated OA (SVOOA) and
low-volatility oxygenated OA (LVOOA). ME-2 analysis of the seasonal data sets
(spring, summer and autumn) showed a higher variability in the OA sources
that was not detected in the combined March–December data set; this
variability was explored with the triangle plots f44 : f43 f44 : f60, in which a
high variation of SVOOA relative to LVOOA was observed in the f44 : f43
analysis. Hence, it was possible to conclude that, when performing source
apportionment to long-term measurements, important information may be lost
and this analysis should be done to short periods of time, such as
seasonally. Further analysis on the atmospheric implications of these OA
sources was carried out, identifying evidence of the possible contribution
of heavy-duty diesel vehicles to air pollution during weekdays compared to
those fuelled by petrol.
... The contribution elsewhere in Europe was smaller. The effect of the changing emissions on CCN may be different because organic compounds can also act as a source of new particles from nucleation (Carslaw et al., 2013b;Riccobono et al., 2014;, which could amplify the response. ...
The literature on atmospheric particulate matter (PM), or atmospheric aerosol, has increased enormously
over the last 2 decades and amounts now to some 1500–2000 papers per year in
the refereed literature. This is in part due to the enormous advances in
measurement technologies, which have allowed for an increasingly accurate
understanding of the chemical composition and of the physical properties of
atmospheric particles and of their processes in the atmosphere. The growing
scientific interest in atmospheric aerosol particles is due to their high
importance for environmental policy. In fact, particulate matter constitutes
one of the most challenging problems both for air quality and for climate
change policies. In this context, this paper reviews the most recent results
within the atmospheric aerosol sciences and the policy needs, which have
driven much of the increase in monitoring and mechanistic research over the
last 2 decades.
The synthesis reveals many new processes and developments in the science
underpinning climate–aerosol interactions and effects of PM on human health
and the environment. However, while airborne particulate matter is
responsible for globally important influences on premature human mortality,
we still do not know the relative importance of the different chemical
components of PM for these effects. Likewise, the magnitude of the overall
effects of PM on climate remains highly uncertain. Despite the uncertainty
there are many things that could be done to mitigate local and global
problems of atmospheric PM. Recent analyses have shown that reducing black
carbon (BC) emissions, using known control measures, would reduce global
warming and delay the time when anthropogenic effects on global temperature
would exceed 2 °C. Likewise, cost-effective control measures on
ammonia, an important agricultural precursor gas for secondary inorganic
aerosols (SIA), would reduce regional eutrophication and PM concentrations in
large areas of Europe, China and the USA. Thus, there is much that could be
done to reduce the effects of atmospheric PM on the climate and the health of
the environment and the human population.
A prioritized list of actions to mitigate the full range of effects of PM is
currently undeliverable due to shortcomings in the knowledge of aerosol
science; among the shortcomings, the roles of PM in global climate and the
relative roles of different PM precursor sources and their response to
climate and land use change over the remaining decades of this century are
prominent. In any case, the evidence from this paper strongly advocates for
an integrated approach to air quality and climate policies.
... The reasons for these discrepancies are discussed at length elsewhere (e.g. Carslaw et al., 2013) and remain an area of active research for both LDVs and HDVs. It is anticipated and understood that NO x emissions rates will need to be updated as more knowledge on the realworld performance of EURO V HDVs, but especially EURO VI vehicles come to light. ...
... The reasons for these discrepancies are discussed at length elsewhere (e.g. Carslaw et al., 2013) and remain an area of active research for both LDVs and HDVs. It is anticipated and understood that NO x emissions rates will need to be updated as more knowledge on the realworld performance of EURO V HDVs, but especially EURO VI vehicles come to light. ...
Hydraulic fracturing (fracking) has been used extensively in the US and Canada since the 1950s and offers the potential for significant new sources of oil and gas supply. Numerous other countries around the world (including the UK, Germany, China, South Africa, Australia and Argentina) are now giving serious consideration to sanctioning the technique to provide additional security over the future supply of domestic energy. However, relatively high population densities in many countries and the potential negative environmental impacts that may be associated with fracking operations has stimulated controversy and significant public debate regarding if and where fracking should be permitted. Road traffic generated by fracking operations is one possible source of environmental impact whose significance has, until now, been largely neglected in the available literature. This paper therefore presents a scoping-level environmental assessment for individual and groups of fracking sites using a newly-created Traffic Impacts Model (TIM). The model produces estimates of the traffic-related impacts of fracking on greenhouse gas emissions, local air quality emissions, noise and road pavement wear, using a range of hypothetical fracking scenarios to quantify changes in impacts against baseline levels.
... The mean VSP at the site is about 19±9 kW/t and changes only by ±1 kW/t across the different vehicle ages. We know from previous measurements that the emission factor at this load is quite constant, as also (Bishop and Stedman, 2008;Carslaw et al., 2013) find across the model years for both, US and European cars. Hence we conclude that on-road driving conditions across age brackets are remarkably stable and thus perfectly suited for your time-series analysis. ...
Vehicle emission control systems have been found to degrade with use resulting in increasing emission rates with vehicle age. Standard European data for deterioration factors have only been based on a sample of vehicles with limited high mileage ranges, with only few Euro 3 and Euro 4 vehicles, and on laboratory tests only. Here we present deterioration rates derived from more than 110 0 000 records collected over the past thirteen years from on-road emission remote sensing in Zurich/Switzerland. Deterioration rates for hot NO x and CO emissions of older gasoline vehicles are much lower than assumed so far, but significantly higher for Euro 3 and Euro 4 cars. There is no evidence of high emitters but equipment gradually degrades across the fleet. Deterioration rates do not seem to depend on engine load. Routine idle emission tests have not resulted in measurable emission reductions of the inspected vehicles. National emission inventories should be updated in the light of this new data.
... With the proposal for a PEMS element in Euro 6c type approval from September 2017 (Delphi, 2013) the development of a robust yet practical road grade estimation methodology for PEMS analysis will be very important to assist the analysis of onroad test data and quantify the relationship between power output and exhaust emission. Whilst this research focused on CO 2 emission, it is expected that road grade will have an even greater influence on the emission of other exhaust pollutant such as NO x where a higher proportion of emissions are related to high power events (Carslaw et al., 2013). ...
... Several campaigns have been conducted in the UK since 2008, with results described in (Carslaw et al. 2011;Carslaw et al. 2013; Rhys-Tyler and Bell 2012). ...
... Earlier work reported results from a commercial RSD (remote sensing detector) instrument d an AccuScan RSD-4600 instrument supplied by Environmental Systems Products (Carslaw et al., 2011(Carslaw et al., , 2013Rhys-Tyler and Bell, 2012;Rhys-Tyler et al., 2011). While the commercial instrumentation has proved to be effective, a critical deficiency for the current work is its ability to measure only NO and not NO 2 . ...
In this paper we report the first direct measurements of nitrogen
dioxide (NO2) in the UK using a vehicle emission remote
sensing technique. Measurements of NO, NO2 and ammonia
(NH3) from almost 70,000 vehicles were made spanning vehicle
model years from 1985 to 2012. These measurements were carefully matched
with detailed vehicle information data to understand the emission
characteristics of a wide range of vehicles in a detailed way. Overall
it is found that only petrol fuelled vehicles have shown an appreciable
reduction in total NOx emissions over the past 15-20
years. Emissions of NOx from diesel vehicles, including those
with after-treatment systems designed to reduce emissions of
NOx, have not reduced over the same period of time. It is
also evident that the vehicle manufacturer has a strong influence on
emissions of NO2 for Euro 4/5 diesel cars and urban buses.
Smaller-engined Euro 4/5 diesel cars are also shown to emit less
NO2 than larger-engined vehicles. It is shown that
NOx emissions from urban buses fitted with Selective
Catalytic Reduction (SCR) are comparable to those using Exhaust Gas
Recirculation for Euro V vehicles, while reductions in NOx of
about 30% are observed for Euro IV and EEV vehicles. However, the
emissions of NO2 vary widely dependent on the bus technology
used. Almost all the NOx emission from Euro IV buses with SCR
is in the form of NO, whereas EEV vehicles (Enhanced Environmentally
friendly Vehicle) emit about 30% of the NOx as
NO2. We find similarly low amounts of NO2 from
trucks (3.5-12t and >12t). Finally, we show that NH3
emissions are most important for older generation catalyst-equipped
petrol vehicles and SCR-equipped buses. The NH3 emissions
from petrol cars have decreased by over a factor of three from the
vehicles manufactured in the late 1990s compared with those manufactured
in 2012. Tables of emission factors are presented for
NOx, NO2 and NH3 together with
uncertainties to assist the development of new emission inventories.
Hydrogen has emerged as a promising clean energy carrier for automobile applications. Magnesium hydride (MgH2) has garnered significant attention as a potential H2 storage material due to its high capacity and low cost. Nonetheless, its practical use is hindered by unfavorable H2 sorption kinetics and operating temperatures. This study presents a novel approach to enhance the H2 storage properties of MgH2 by adding graphene oxide (GO) supported tin dioxide (cSnO2) nanoparticles. The as-prepared catalysts (GO/SnO2) were synthesized through modified chemical methods followed by ball-milling with MgH2 characterized using various techniques, including X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray and Fourier transform infrared spectroscopy (FTIR). The catalytic effect of GO-SnO2 nanoparticles on MgH2 was investigated through systematic H2 sorption studies as well as thermal analysis. Results demonstrate that the onset temperature for H2 desorption was significantly reduced, and the dehydrogenation kinetics were substantially enhanced.
Twenty years on from the first edition of Pollution and the topic remains high in the public awareness. Environmental pollution is now a major area of research, consultancy and technological development and is a priority for the political agendas of both the developed and developing worlds.
The fifth edition of this book is fully updated, and includes an entirely new chapter on Climate Change, presenting an authoritative view on this topic. Chapters in fast moving areas have been completely revised and several newcomers have joined the original set of authors.
This popular book has proved invaluable as a teaching resource for two decades and is frequently used as a reference by practitioners in the field. Readers of earlier editions will benefit from updates on technologies such as nanoscience, and the legislative changes that have occurred since the fourth edition in 2001.
Brazil is the 9th largest producer of vehicles in the world, with 62.7% of the global fleet of Flex-Fuel Vehicles (FFVs). These vehicles used in Brazil operate with E27 (anhydrous ethanol used for gasohol blending) or E100 hydrous ethanol or any blend between these two. In recent years, Fortaleza city/Brazil has implemented Bus Rapid Transit (BRT) systems in two of the city’s most important avenues. Fortaleza BRT has two-way busways on the central verge of the roadway separated by two lanes from mixed traffic used by passenger cars, light commercial trucks, motorcycles, and heavy-duty vehicles. These systems have been regarded as a potential solution to improve some traffic factors, for only Buses, such as the average driving speed, thus benefiting both transportation and the environment. Thus, this research proposes a comprehensive impact evaluation of an FFV when traveling on BRT corridors, specifically on lanes from mixed traffic, and evaluate the emission factors, specifically on lanes from mixed traffic, composed of a wide variety of vehicle types. All tests in this study were performed at lanes from mixed traffic. Carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), and hydrocarbons (HCt) emissions were experimentally measured using a Portable Emission Measurement System (PEMS) under real-world traffic conditions in Fortaleza. FFV tailpipe emissions from E27, E85, and E100 fuels were highly sensitive to the power demand and traffic flow. Additionally, the VSP (Vehicle Specific Power) methodology was applied to characterize the driving modes. Overall, results showed the following: CO2 was, by far, the most highly emitted gas; the highest CO release occurred with E85 blend; NOx emission factors were similar for both E27 and E85, but much greater for E100; and HCt did not show a pattern, presenting both the highest and lowest emission levels with E100.
Vehicle emission remote sensing devices have been widely used for monitoring and assessing the real-world emission performance of vehicles. They are also well-suited to identify candidate high emitting vehicles as remote sensing surveys measure the on-road, real-driving emissions (RDE) of a high proportion of the operational vehicle fleet passing through a testing site. This study uses the Gumbel distribution to characterize the fuel-specific NOx emission rates (g·kg⁻¹) from diesel vans (formally referred to as light commercial vehicles or LCVs) and screen candidate high emitting vehicles. Van emission trends of four European countries (Belgium, Sweden, Switzerland and the UK) from Euro 3 to Euro 6a/b have been studied, and the impact of road grade on candidate Euro 6a/b high-emitters is also evaluated. The measurements of Euro 6a/b fleets from four countries are pooled together, and a consistent 4% of candidate high-emitters are found in both class II and class III Euro 6a/b vans, accounting for an estimated 24% and 21% total NOx emissions respectively. The pooled four country data is differentiated by vehicle models and manufacture groups. Engine downsizing of Euro 6a/b class II vans is suspected to worsen the emission performance when vehicles are driven under high engine load. The VW Group is found to be the manufacture with cleanest NOx emission performance in the Euro 6a/b fleets. By distinguishing high-emitters from normally behaving vehicles, a more robust description of fleet behaviour can be provided and high-emitting vehicles targeted for further testing by plume chasing or in an inspection garage. If the vehicle is found to have a faulty, deteriorated or tampered emission after-treatment system, the periodic vehicle inspection safety and environmental performance certificate could be revoked.
Light commercial vehicles (LCVs) account for about 10-15% of road traffic in Europe. There have only been few investigations on their on-road emission performance. Here, on-road remote sensing vehicle emission measurements from 18 locations across four European countries are combined for a comprehensive analysis of NO
x
and smoke emission rates from diesel LCV in the past two decades. This allows differentiating the performance by emission standards, model years, curb weights, engine loads, manufacturers, vehicle age, and temperature, as well as by measurement devices. We find a general consistency between devices and countries. On-road NO
x
emission rates have been much higher than type approval limit values for all manufacturers, but some perform systematically better than others. Emission rates have gone down only with the introduction of Euro 6a-b emission standards since the year 2015. Smoke emission rates are considered a proxy for particulate emissions. Their emissions have decrease substantially from the year 2010 onward for all countries and size classes measured. This is consistent with the substantial tightening of the particulate matter emission limit value that typically forced the introduction of a diesel particulate filter. The average NO
x
emission rate increases with engine load and decreasing ambient temperatures, particularly for Euro 4 and 5 emission classes. This explains to a large extent the differences in the absolute level between the measurement sites together with differences in fleet composition. These dependencies have already been observed earlier with diesel passenger cars; they are considered part of an abnormal emission control strategy. Some limited increase of the NO
x
emission rate is observed for Euro 3 vehicles older than 10 years. The strong increase for the youngest Euro 6 LCVs might rather reflect technology advances with successively younger models than genuine deterioration. However, the durability of emission controls for Euro 6 vehicles should be better monitored closely. Smoke emission rates continuously increase with vehicle age, suggesting a deterioration of the after-treatment system with use.
The quantification and comparison of NOX emission from in-situ car fleets, and identification of the highest emitters is an ongoing challenge. This challenge will become more important as new and increasingly complex emissions removal systems penetrate the market. We combine real-world data with new-to-the-field statistical methods to describe fleet-scale emissions behaviours and identify candidate gross-emitter vehicles.
19,605 passenger cars were observed using a Remote Sensing Device across Aberdeen in 2015. Of these, 736 were Euro 6 Passenger Cars. The distribution of observed pollutant per unit of fuel burnt ratios for most fuel type and Euro standards followed an asymmetrical shape best characterised by the Gumbel distribution. The Gumbel distribution approach was not able to fully replicate the distribution of measurements of petrol or Euro 6 diesel cars due to the presence of a subset of high-emitting outliers, ranging from the 13th percentile for Euro 3 petrol to the 2nd percentile for Euro 6 petrol, with Euro 6 diesel having a 5th percentile outlier value. No outlier fraction was observed for pre-Euro 6 diesels.
The off-model fractions resembled Gumbel distributed data and in some cases could be modelled as a separate distribution with the fleet behaving as a superposition of them. It is shown that VSP was not directly linked to this behaviour and it is hypothesised that it is caused by the emissions control systems operating sub-optimally. The reasons for sub-optimal operation are beyond the scope of this paper but may be linked to air-fuel mixture sensors, cold-start running and deterioration of the catalytic converter. Larger data-sets with more Euro 6 passenger cars are required to fully test this. Application of this methodology to larger data sets from more widely deployed remote sensing devices will allow observers to identify potentially problematic vehicles for further investigation into their emission control systems.
This paper reports upon and analyses vehicle emissions measured by the Emissions Detecting and Reporting (EDAR) system, a Vehicle Emissions Remote Sensing System (VERSS) type device, used in five UK based field campaigns in 2016 and 2017. In total 94,940 measurements were made of 75,622 individual vehicles during the five campaigns. The measurements are subset into vehicle type (bus, car, HGV, minibus, motorcycle, other, plant, taxi, van, and unknown), fuel type for car (petrol and diesel), and EURO class, and particulate matter (PM), nitric oxide (NO) and nitrogen dioxide (NO2) are reported. In terms of recent EURO class emission trends, NO and NOx emissions decrease from EURO 5 to EURO 6 for nearly all vehicle categories. Interestingly, taxis show a marked increase in NO2 emissions from EURO 5 to EURO 6. Perhaps most concerningly is a marked increase in PM emissions from EURO 5 to EURO 6 for HGVs. Another noteworthy observation was that vans, buses and HGVs of unknown EURO class were often the dirtiest vehicles in their classes, suggesting that where counts of such vehicles are high, they will likely make a significant contribution to local emissions. Using Vehicle Specific Power (VSP) weighting we provide an indication of the magnitude of the on-site VERSS bias and also a closer estimate of the regulatory test/on-road emissions differences. Finally, a new ‘EURO Updating Potential’ (EUP) factor is introduced, to assess the effect of a range of air pollutant emissions restricted zones either currently in use or marked for future introduction. In particular, the effects of the London based Low Emission Zone (LEZ) and Ultra-Low Emissions Zone (ULEZ), and the proposed Birmingham based Clean Air Zone (CAZ) are estimated. With the current vehicle fleet, the impacts of the ULEZ and CAZ will be far more significant than the LEZ, which was introduced in 2008.
Internet of Things (IoT) can help transport authorities to address the challenge of road traffic air pollution. The extent to which it can help varies across the different measures and solutions adopted. To some it is fundamental, to others it improves a solution that could function without IoT. The main shorter‐term approaches to reducing traffic pollution are reducing vehicle usage via green modal shift, vehicle bans, telecommuting and trip‐chaining; making vehicles cleaner, e.g. improved air filtering and electric vehicles; optimizing driver and vehicle performance; reducing congestion; smoothing traffic flow; and reducing exposure, e.g. by moving pedestrians away from heavy traffic or vice versa. Longer‐term measures included better urban planning. An emerging area of research, development, and demonstrations in IoT and transport is the use of Vehicle‐to‐Infrastructure communications to reduce congestion and emissions. A great example of a large‐scale distributed network of real‐time air quality IoT sensors is the Newcastle Urban Observatory.
Continuous air quality monitoring networks were commissioned in the mid-twentieth century throughout the developed world to underpin the understanding of air pollution. These monitoring networks have produced a vast observational record which continues to grow. However, these data are generally used for simple tasks such as checking for compliance to legal standards or guidelines and the additional information contained in the data sets is not well leveraged to aid scientific understanding and inform policy makers. This thesis addresses this issue and has the goal of extracting additional information from "routine"' air quality monitoring data using new, and novel data analyses with a focus on the impact of transportation activities across Europe. Specifically, this thesis outlines the development of bivariate polar plots with pair-wise statistics to aid source apportionment, the development of a European air quality database which much of this thesis's work is based on, a European-wide analysis of roadside nitrogen dioxide (NO2), and the development of a framework and software to robustly detect and quantify changes in pollutant concentrations. The additional functionality of bivariate polar plots was useful for isolating the natural and anthropogenic sources of pollutants and is now included in the open source openair R package. The NO2 analysis revealed that directly emitted NO2 from road vehicles is decreasing across Europe and assumed emissions are too high resulting in pessimistic projections of future compliance. This conclusion is very important for policy makers to consider in their planning of disruptive interventions, most relevant of which are low emission zones because the observations suggest that the outlook is better than traditionally thought. For those analysing trends, a new technique has been developed that is highly effective at robustly characterising and quantifying the effects of interventions and the tools developed are available in the form of the open source rmweather R package.
A review of the literature from 2013 related to automotive wastes is presented. Topics include solid wastes from autobodies and tires, and vehicle emissions to soil and air as a result of the use of conventional and alternative fuels. Potential toxicological and health risks related to automotive wastes are also discussed.
Approximately 600,000 deaths occur worldwide annually for children up to five years of age. Pneumonia is the leading cause and more than 50% of these deaths are attributed to air pollution. It is still responsible for increased risk of respiratory infections, asthma, adverse neonatal conditions and congenital anomalies. Air pollution also affects the cognitive development of children and induces future development of chronic diseases in adulthood. In order to define criteria based on remote sensing measurements to identify Otto cycle light duty vehicles (LDV) with high emissions of carbon monoxide, hydrocarbons or nitric oxide it was used secondary data produced by Remote Sensing do Brasil Ltda, from which 179,142 in-use vehicles were selected, that belongs to the city of São Paulo’s current fleet. All those vehicles had complete measurements of emission of carbon monoxide (CO), hydrocarbons (HC) and nitric oxide (NO), and also speed and acceleration of the vehicle during measurements, and slope of the track at the place chosen for the measurements. Statistical models of the Generalized Additive Models for Location, Scale and Shape (GAMLSS) class were adjusted to test the influence of fuel type, Vehicle Specific Power (VSP) and of the Brazilian Vehicle Emission Control Program [Proconve] phases on CO, HC and NO emissions, measured using Remote Sensing Device (RSD). The emissions were then conceptually subdivided into two groups: vehicles with normal and abnormal emission, for the various pollutants in vehicles of L3, L4 and L5 phases of Proconve, which were of interest for the air quality management. Latent variables were defined to indicate the distribution of vehicles in relation to those groups and phases. The algorithm Expectation – Maximization (EM) was employed to identify all parameters of the distributions. We use the 98% percentiles of the statistical distribution set, for vehicles of groups with normal emissions to determine the limit values for vehicles with high emissions of pollutants and Proconve Phase. Therefore, the Type I Error was set at 2% and this percentage was established considering the Type II Error to point the vehicle as having normal emission when in fact it is a high emitter. Through this approach, the indicative values of vehicles with high emissions according to the pollutant and the Proconve Phase were determined. Results of emissions measured with the RSD technique indicated a decrease in CO and HC emissions according to the Proconve Phase. For the NO, the emissions behavior did not follow the reductions imposed by the Proconve Phases. It was found that newer vehicles – year model from 2005 to 2009 – exclusively gasohol-powered vehicles, were the ones that presented the highest NO emissions. Several possible causative factors of this differential behavior of NO were discussed in this study. A significant increase in the environmental concentrations of Nitrogen Oxides (NOx) was detected in 2007, when this parameter was monitored in the winter period. This may indicate the influence of the high emitter vehicles, but it requires a more in-depth cause-effect study for confirmation of this behavior.
Vehicle emissions are a major contributor to air pollution in cities and have serious health impacts to their inhabitants. On-road remote sensing is an effective and economic tool to monitor and control vehicle emissions. In this review, the mechanism, accuracy, advantages and limitations of remote sensing were introduced. Then the applications and major findings of remote sensing were critically reviewed. It was revealed that the emission distribution of on-road vehicles was highly skewed so that the dirtiest 10% vehicles accounted for over half of the total fleet emissions. Such findings highlighted the importance and effectiveness of using remote sensing for in situ identification of high-emitting vehicles for further inspection and maintenance programs. However, the accuracy and number of vehicles affected by screening programs were greatly dependent on the screening criteria. Remote sensing studies showed that the emissions of gasoline and diesel vehicles were significantly reduced in recent years, with the exception of NOx emissions of diesel vehicles in spite of greatly tightened automotive emission regulations. Thirdly, the experience and issues of using remote sensing for identifying high-emitting vehicles in Hong Kong (where remote sensing is a legislative instrument for enforcement purposes) were reported. That was followed by the first time ever identification and discussion of the issue of frequent false detection of diesel high-emitters using remote sensing. Finally, the challenges and future research directions of on-road remote sensing were elaborated.
How does remote sensing work?
What is best practice for on-road emissions sensing?
What’s the possible role of remote sensing for in-use surveillance?
Find answers in the recent White Paper issued by the ICCT.
In this paper we present the results corresponding to on-road traffic emissions measurements obtained during two field campaigns developed in the Madrid region (Spain) during 2014 and 2015 in the framework of the CORETRA project. The experimental strategy was based on the use of a RSD 4600 remote sensor in interurban roads. These measurements have produced a global database of > 190,000 vehicles with their associated emission data (NO/CO2, HC/CO2 and CO/CO2), which can be considered representative of the current Spanish circulating fleet. The results of M1 vehicles were analysed according to their distribution by Euro Standard and engine model. One of the relevant findings is that, despite the progressive introduction of increasingly stringent standards, no NO emission reduction is observed for diesel vehicles with time, although this behavior shows significative differences among brands and engine models.
We have also investigated the presence of “high emitter” (HE) vehicles in the Spanish M1 circulating fleet and most of the HE detected corresponded to diesel vehicles with very high NO/CO2 values. With these results at hand, we strongly propose the future incorporation of the “high emitter vehicle” definition into the European environmental legislation, as well as the establishment of specific strategies in each country/region in order to identify these anomalous vehicles. Identification and repair of HE vehicles within the European circulating fleets, although are not easy tasks, should be considered very important for the improvement of air quality in the EU. The use of non-intrusive optical technologies (i.e. RSD) is an excellent option to provide instantaneous real emission data of each individual vehicle without disturbing traffic and for on-road fleet monitoring. In summary, it is a good strategy to obtain valuable information about the long term surveillance of real vehicle emission trends, specially after the introduction of new standard.
Analysing on-road emissions from remote sensing campaigns (Zurich/CH)
In the agricultural sector, toxic substances can be released into the atmosphere. In recent years, Europe has encountered a significant environmental issue related to the dispersion of pesticides during maize seeding, especially when performed with pneumatic seed drills. This phenomenon can be very dangerous for insects, as the dispersed dust contains pesticides (insecticides, fungicides, etc.) used to dress maize seeds. On the basis of these considerations, experimental tests have been carried out using a filtration system to clean the airflow that exits from the fan of pneumatic maize seed drills.
The tested filtration system does not interfere with the seeding quality because the vacuum level observed within filtration system assembled on the seeder (5.7 kPa) is 27% higher than the correct vacuum level to guarantee good seeding quality (4.2 kPa). In addition, it enables the reduction of the risk of environmental contamination as no dust deposits were found at different distances from the machine.
The use of a filtration system shows advantages in term of environmental and operator safety because dangerous materials are contained in the filter case, thus avoiding contamination of neighbouring areas and the machinery used (tractor and seed drill).
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The literature on atmospheric particulate matter (PM), or atmospheric aerosol, has increased enormously over the last 2 decades and amounts now to some 1500–2000 papers per year in the refereed literature. This is in part due to the enormous advances in measurement technologies, which have allowed for an increasingly accurate understanding of the chemical composition and of the physical properties of atmospheric particles and of their processes in the atmosphere. The growing scientific interest in atmospheric aerosol particles is due to their high importance for environmental policy. In fact, particulate matter constitutes one of the most challenging problems both for air quality and for climate change policies. In this context, this paper reviews the most recent results within the atmospheric aerosol sciences and the policy needs, which have driven much of the increase in monitoring and mechanistic research over the last 2 decades.
The synthesis reveals many new processes and developments in the science underpinning climate–aerosol interactions and effects of PM on human health and the environment. However, while airborne particulate matter is responsible for globally important influences on premature human mortality, we still do not know the relative importance of the different chemical components of PM for these effects. Likewise, the magnitude of the overall effects of PM on climate remains highly uncertain. Despite the uncertainty there are many things that could be done to mitigate local and global problems of atmospheric PM. Recent analyses have shown that reducing black carbon (BC) emissions, using known control measures, would reduce global warming and delay the time when anthropogenic effects on global temperature would exceed 2 °C. Likewise, cost-effective control measures on ammonia, an important agricultural precursor gas for secondary inorganic aerosols (SIA), would reduce regional eutrophication and PM concentrations in large areas of Europe, China and the USA. Thus, there is much that could be done to reduce the effects of atmospheric PM on the climate and the health of the environment and the human population.
A prioritized list of actions to mitigate the full range of effects of PM is currently undeliverable due to shortcomings in the knowledge of aerosol science; among the shortcomings, the roles of PM in global climate and the relative roles of different PM precursor sources and their response to climate and land use change over the remaining decades of this century are prominent. In any case, the evidence from this paper strongly advocates for an integrated approach to air quality and climate policies.
More than a third of Europe’s population is exposed to excessive levels of air pollution, in particular along busy roads. The EU has responded by tightening exhaust emission standards for vehicles, among others. Our research however finds that this has only partially been effective: Today’s diesel cars emit still as much NOx than the models 20 years ago. Hence, for future air quality there are a number of important questions:
• Will the next generation of diesel cars perform significantly better on the road – or still only in the laboratory?
• How quickly will the legislative test cycles be amended so that emission reductions in the laboratory are also translated to real emission reductions on the road?
• Are subsidies for diesel fuel still warranted given that average diesel cars have much higher pollutant emissions but not less CO2 emissions than gasoline cars anymore?
Research Report 2012 & 2013: an important focus of the past year has been the completion and delivery of our submission to the Research Excellence Framework (REF 2014). The scope of the previous exercise by the Higher Education Funding Council (RAE 2008) – was extended to include the assessment of not only our research outputs, but also the impacts of these outputs on industry, economy and society. The latter focus plays to one of our strengths as a provider of high-level independent research and consultancy to government and regulators. For our research activities we have held ISO9001 accreditation continuously since 1995. During 2012 and 2013, our research impacts have included the following: Path-breaking research has exposed the inadequacy of NOX emission controls on diesel vehicles and shaped European legislation on low emission zones (Dr James Tate see page 6 ''Surveying Vehicle Emissions''). Valuations of travel time savings and forecasts of the demand response to travel time savings have formed key inputs to the economic case for High Speed 2 (Dr James Laird and Professor Peter Mackie see page 8 ''Economic Appraisal and Evaluation''; Professor Mark Wardman and Dr Richard Batley see pages 10 and 12 ''Modelling and Valuing Reliability and Punctuality'' and ''Passenger Demand for Rail Travel''). Long-standing research on the effectiveness of Intelligent Speed Adaptation (ISA) has been translated into changes to the Euro NCAP accreditation scheme (Professor Oliver Carsten, Dr Samantha Jamson) Publications covering our ISA research are listed on pages 22 – 25 under authors Carsten; Chorlton; Jamson and Lai. Research activities at ITS cover a diverse set of themes and have engaged a vast array of sponsors and stakeholders. On pages 3 – 21 our research projects are listed alphabetically under theme headings. Research highlights of 2012 and 2013 include: A major new project with expert partners and cities across Europe, CH4LLENGE expands understanding, transfers knowledge, and supports implementation of schemes in sustainable urban mobility planning (Dr Caroline Mullen see page 4). In 2013, the Department for Transport published five reports (amounting to some 500 pages of output) on the valuation of journey time savings produced by Professor Mark Wardman, Dr Richard Batley, Dr James Laird, Professor Peter Mackie and Phill Wheat (the reports can be found on our website). ITS researchers submitted evidence to the House of Commons Transport Select Committee Inquiry on winter resilience. In their submission, Professor Greg Marsden and Jeremy Shires drew on key issues from the Disruption project (see page 15), which included a large scale survey of UK regions affected by snow, storms and flooding during January 2013. Dr Susan Grant-Muller is a co-investigator on a Big Data centre recently funded by the Economic and Social Research Council, a collaborative venture with other academic schools at Leeds and University College London. The grant will help to establish a new Master's course in Geography and Business and will fund a Consumer Data Research Centre (CDRC). Staff achievements during 2012 and 2013 include the following highlights: Greg Marsden, Stephane Hess and Simon Shepherd were promoted to Professor. Charlotte Kelly was awarded a 3-year fellowship by the National Institute for Clinical Excellence (NICE). PhD student Rawia El Rashidy is one of ten women at the University of Leeds to be honoured as a 'Woman of Achievement'. This was in recognition of her being awarded a gold medal in the 'Young Researchers in Europe' competition 2012.
Quantile regression is a way to estimate the conditional quantiles of a response variable distribution in the linear model that provides a more complete view of possible causal relationships between variables in ecological processes. Typically, all the factors that affect ecological processes are not measured and included in the statistical models used to investigate relationships between variables associated with those processes. As a consequence, there may be a weak or no predictive relationship between the mean of the response variable (y) distribution and the measured predictive factors (X). Yet there may be stronger, useful predictive relationships with other parts of the response variable distribution. This primer relates quantile regression estimates to prediction intervals in parametric error distribution regression models (eg least squares), and discusses the ordering characteristics, interval nature, sampling variation, weighting, and interpretation of the estimates for homogeneous and heterogeneous regression models.
We report the dendrimer-mediated synthesis and shape evolution of gold–silver alloy nanoparticles (Au–Ag alloy NPs) with different metal compositions. In this study, amine-terminated generation 5 poly(amidoamine) dendrimers were used as stabilizers to prepare Au–Ag alloy NPs with different gold atom/silver atom/dendrimer molar ratios without the assistance of additional reducing agents. Following a one-step acetylation reaction to transform the dendrimer terminal amines to acetyl groups, a series of Au–Ag alloy NPs with surface acetyl groups were formed. The alloy NPs before and after acetylation reaction were characterized using 1H NMR, UV–vis spectrometry, transmission electron microscopy, inductively coupled plasma-optical emission spectroscopy, and X-ray absorption coefficient measurements. We showed that the optical property, the size, and the morphology of the bimetallic NPs were greatly affected by the metal composition and their surface modification. At the constant total metal atom/dendrimer molar ratio, the alloy NPs experienced a shape evolution from spherical particles and polyhedrons to curved nanowires with the Au content. Acetylation of the dendrimer terminal amines seemed to thicken the nanowires. The formed Au–Ag alloy NPs were stable at different pH (pH 5–8) and temperature (4–50 °C) conditions. X-ray absorption coefficient measurements showed that the attenuation intensity of the alloy NPs was dependent on both the metal composition and surface functional groups. At a given metal composition, the X-ray attenuation intensity of the binary NPs was enhanced after acetylation. The formed metal alloy NPs with tunable size and shape prepared using the dendrimer stabilizers may be used in a range of applications in catalysis, sensing, and biomedical sciences.
Traffic-related emissions represent a major component of airborne pollution. Historically, dynamometer testing has been most widely used to estimate vehicle emission rates, and these emission rates, in turn, have been used as inputs when modeling traffic-related air quality impacts. However, such conventional drive cycle testing is not considered strictly representative of vehicles under real driving conditions. Therefore, in recent years, significant scientific effort has been focused on the measurement and analysis of real-world vehicle emissions. Here, the use of vehicle emissions monitoring methods (e.g., in-situ methods such as tunnel, inverse dispersion, and remote sensing studies, and in-traffic measures such as probe vehicle and car chaser studies) to provide real-world emission estimates is reviewed and discussed in detail. Advantages and disadvantages are identified for the different vehicle emissions monitoring methods, both relative to dynamometer-based approaches and each other. Potential applications of different approaches are also discussed, with particular attention being placed on their complementary use.
This research aims to determine the overall effects that a vehicle's short-term operating history has on its subsequent emissions, and how Vehicle Specific Power (VSP)-based vehicle emission models could be improved to account for these effects. Current VSP-based emission models, such as the U.S. EPA's MOtor Vehicle Emission Simulator (MOVES), only predict emissions based on instantaneous vehicle activity and the corresponding VSP value; the past short-term vehicle operational activity is not taken into account (e.g., the last 10–20 s of operation). For example, instantaneous vehicle emissions could be affected by a hard acceleration vs. a deceleration event at that particular point in time. This paper attempts to determine the accuracy of VSP-based emission models, which may suffer due to the fact that the history effects are being overlooked.A number of experiments were carried out in order to determine the anomalies resulting from instantaneous estimation as opposed to taking short-term vehicle operating history into account. These experiments compare model estimates with actual emission measurements. A quantitative analysis shows that the higher power operating modes (such as modes 33, 35, 37, 38, and 40 in MOVES) had the greatest variability – sometimes in the range of 60–100% – due to the effects that vehicle operating history has on carbon monoxide (CO). Hydrocarbons (HC) in higher power operating modes also vary 40–60% depending on the driving cycle. For lower power operating modes (e.g., MOVES modes 1–30), the uncertainty for all pollutants was significantly less. It was also established that the carbon dioxide (CO2) and nitrogen oxide (NOx) estimations conducted by MOVES were least affected by the vehicle operational history effects compared with other emissions. As such, MOVES emission results are more accurate for mild to normal driving cycles, but there is greater uncertainty for higher power driving cycles.
A simple minimization problem yielding the ordinary sample quantiles in the location model is shown to generalize naturally to the linear model generating a new class of statistics we term "regression quantiles." The estimator which minimizes the sum of absolute residuals is an important special case. Some equivariance properties and the joint aymptotic distribution of regression quantiles are established. These results permit a natural generalization to the linear model of certain well-known robust estimators of location. Estimators are suggested, which have comparable efficiency to least squares for Gaussian linear models while substantially out-performing the least-squares estimator over a wide class of non-Gaussian error distributions.
Ambient trends in nitrogen oxides (NOx) and nitrogen dioxide (NO2) for many air pollution monitoring sites in European cities have stabilised in recent years. The lack of a decrease in the concentration of NOx and in particular NO2 is of concern given European air quality standards are set in law. The lack of decrease in the concentration of NOx and NO2 is also in clear disagreement with emission inventory estimates and projections. This work undertakes a comprehensive analysis of recent vehicle emissions remote sensing data from seven urban locations across the UK. The large sample size of 84,269 vehicles was carefully cross-referenced to a detailed and comprehensive database of vehicle information. We find that there are significant discrepancies between current UK/European estimates of NOx emissions and those derived from the remote sensing data for several important classes of vehicle. In the case of light duty diesel vehicles it is found that NOx emissions have changed little over 20 years or so over a period when the proportion of directly emitted NO2 has increased substantially. For diesel cars it is found that absolute emissions of NOx are higher across all legislative classes than suggested by UK and other European emission inventories. Moreover, the analysis shows that more recent technology diesel cars (Euro 3–5) have clear increasing NOx emissions as a function of Vehicle Specific Power, which is absent for older technology vehicles. Under higher engine loads, these newer model diesel cars have a NOx/CO2 ratio twice that of older model cars, which may be related to the increased use of turbo-charging. Current emissions of NOx from early technology catalyst-equipped petrol cars (Euro 1/2) were also found to be higher than emission inventory estimates – and comparable with NOx emissions from diesel cars. For heavy duty vehicles, it is found that NOx emissions were relatively stable until the introduction of Euro IV technology when emissions decreased by about 30%. The more limited data available for urban buses shows that there has been little change in NOx emissions from Euro I to Euro IV. There is general much better consistency across the different estimates of heavy duty vehicle NOx emissions than for light duty vehicles.Highlights► Trends in ambient NOx concentrations have tended to stabilise in recent years. ► Little change in light duty vehicle NOx emissions over 20 years or so. ► Increased diesel car power demand leads to increased NOx for newer vehicles. ► Older catalyst-equipped vehicles emit more NOx than previously thought. ► Important implications at a European level for meeting NO2 limits.
This paper proposes the use of the conditional quantile regression approach for the interpretation of the nonlinear relationships between daily maximum 1-h ozone concentrations and both meteorological and persistence information. When applied to eight years (1992-1999) of data from four monitoring sites in Athens, quantile regression results show that the contributions of the explanatory variables to the conditional distribution of the ozone concentrations vary significantly at different ozone regimes. This evidence of heterogeneity in the ozone values is hidden in an ordinary least-square regression that is confined to providing a single central tendency measure. Furthermore, the utilization of an 'amalgated' quantile regression model leads to a significantly improved goodness of fit at all sites. Finally, computation of conditional ozone densities through a simple quantile regression model allows the estimation of complete density distributions that can be used for forecasting next day's ozone concentrations under an uncertainty framework.
Quantile regression is gradually emerging as a unified statistical methodology for estimating models of conditional quantile functions. By complementing the exclusive focus of classical least squares regression on the conditional mean, quantile regression offers a systematic strategy for examining how covariates influence the location, scale and shape of the entire response distribution. This monograph is the first comprehensive treatment of the subject, encompassing models that are linear and nonlinear, parametric and nonparametric. The author has devoted more than 25 years of research to this topic. The methods in the analysis are illustrated with a variety of applications from economics, biology, ecology and finance. The treatment will find its core audiences in econometrics, statistics, and applied mathematics in addition to the disciplines cited above.
The remote sensing technology developed by the University of Denver provides the first practical approach to routinely characterize real-world, on-road automobile CO and HC exhaust emissions. It has been used to measure the exhaust emissions of more than 1 000 000 vehicles in many locations, This study presents an analysis and comparison of 22 fleet profiles collected by the remote sensor in different regions around the world. Three patterns of emissions distributions and contributions of the fleets are revealed by a hierarchial cluster analysis. The importance of vehicle maintenance on average CO and He emissions is revealed by a quintile analysis. Good maintenance practices in Gothenburg, Sweden, contrast with other locations such as Los Angeles, CA, and Melbourne, Australia. The absolute emissions differences between well- and badly maintained vehicles of any age are considerably larger than observable effects of emission control technology and vehicle age.
For obtaining type approval in the European Union, light-duty vehicles have to comply with emission limits during standardized laboratory emissions testing. Although emission limits have become more stringent in past decades, light-duty vehicles remain an important source of nitrogen oxides and carbon monoxide emissions in Europe. Furthermore, persisting air quality problems in many urban areas suggest that laboratory emissions testing may not accurately capture the on-road emissions of light-duty vehicles. To address this issue, we conduct the first comprehensive on-road emissions test of light-duty vehicles with state-of-the-art Portable Emission Measurement Systems. We find that nitrogen oxides emissions of gasoline vehicles as well as carbon monoxide and total hydrocarbon emissions of both diesel and gasoline vehicles generally remain below the respective emission limits. By contrast, nitrogen oxides emissions of diesel vehicles (0.93 ± 0.39 grams per kilometer [g/km]), including modern Euro 5 diesel vehicles (0.62 ± 0.19 g/km), exceed emission limits by 320 ± 90%. On-road carbon dioxide emissions surpass laboratory emission levels by 21 ± 9%, suggesting that the current laboratory emissions testing fails to accurately capture the on-road emissions of light-duty vehicles. Our findings provide the empirical foundation for the European Commission to establish a complementary emissions test procedure for light-duty vehicles. This procedure could be implemented together with more stringent Euro 6 emission limits in 2014. The envisaged measures should improve urban air quality and provide incentive for innovation in the automotive industry.
A new method is presented which is designed to investigate whether laboratory test data used in the development of vehicle emission models adequately reflects emission distributions, and in particular the influence of high-emitting vehicles. The method includes the computation of a 'high-emitter' or 'emission distribution' correction factor for use in emission inventories. In order to make a valid comparison we control for a number of factors such as vehicle technology, measurement technique and driving conditions and use a variable called 'Pollution Index' (g/kg). Our investigation into one vehicle class has shown that laboratory and remote sensing data are substantially different for CO, HC and NO(x) emissions, both in terms of their distributions as well as in their mean and 99-percentile values. Given that the remote sensing data has larger mean values for these pollutants, the analysis suggests that high-emitting vehicles may not be adequately captured in the laboratory test data. The paper presents two different methods for the computation of weighted correction factors for use in emission inventories based on laboratory test data: one using mean values for six 'power bins' and one using multivariate regression functions. The computed correction factors are substantial leading to an increase for laboratory-based emission factors with a factor of 1.7-1.9 for CO, 1.3-1.6 for HC and 1.4-1.7 for NO(x) (actual value depending on the method). However, it also clear that there are points that require further examination before these correction factors should be applied. One important step will be to include a comparison with other types of validation studies such as tunnel studies and near-road air quality assessments to examine if these correction factors are confirmed. If so, we would recommend using the correction factors in emission inventories for motor vehicles.
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1999. Includes bibliographical references (p. 345-361). by José Luis Jiménez-Palacios. Ph.D.
Atlantic tropical cyclones are getting stronger on average, with a 30-year trend that has been related to an increase in ocean temperatures over the Atlantic Ocean and elsewhere. Over the rest of the tropics, however, possible trends in tropical cyclone intensity are less obvious, owing to the unreliability and incompleteness of the observational record and to a restricted focus, in previous trend analyses, on changes in average intensity. Here we overcome these two limitations by examining trends in the upper quantiles of per-cyclone maximum wind speeds (that is, the maximum intensities that cyclones achieve during their lifetimes), estimated from homogeneous data derived from an archive of satellite records. We find significant upward trends for wind speed quantiles above the 70th percentile, with trends as high as 0.3 +/- 0.09 m s(-1) yr(-1) (s.e.) for the strongest cyclones. We note separate upward trends in the estimated lifetime-maximum wind speeds of the very strongest tropical cyclones (99th percentile) over each ocean basin, with the largest increase at this quantile occurring over the North Atlantic, although not all basins show statistically significant increases. Our results are qualitatively consistent with the hypothesis that as the seas warm, the ocean has more energy to convert to tropical cyclone wind.
The authors undertook a new approach using an old technology to develop a long-path IR photometer that can remotely measure CO emissions from operating vehicles. The University of Denver's instrument consists of three basic units: the source, a detector, and a computer. IR absorption is used to determine the amounts of CO and CO2 emitted by a passing automobile. The IR light source, located on one side of a roadway, sends a collimated beam into a gas filter radiometer equipped with two liquid-nitrogen-cooled indium antimonide photovoltaic detectors. A 4.3-μm bandpass filter isolates the CO2 spectral region, and a 4.6-μm beam passes through a rotating gas filter wheel one-half of which contains a CO and H2 mixture and the other half N2. The rotating wheel modulates the signal and provides both a reference channel and a CO data channel.
NH3 emissions from motor vehicles have been the subject of a number of recent studies due to their potential impact on ambient particulate matter (PM). Highly time-resolved NH3 emissions can be measured and correlated with specific driving events utilizing a tunable diode laser (TDL). It is possible to incorporate NH3 emissions with this new information into models that can be used to predict emissions inventories from vehicles. The newer generation of modal models are based on modal events, with the data collected at second-by-second time resolution, unlike the bag-based emission inventory models such as EMFAC and MOBILE. The development of an NH3 modal model is described in this paper. This represents one of the first attempts to incorporate vehicle NH3 emissions into a comprehensive emissions model. This model was used in conjunction with on-road driving profiles to estimate the emissions of SULEV, ULEV, and LEV vehicles to be 9.4 +/- 4.1, 21.8 +/- 5.2, and 34.9 +/- 6.0 mg/mi, respectively. We also implement this new NH3 model to predict and evaluate the NH3 emission inventory in the South Coast air basin (SoCAB).
In 1990 Congress passed the Clean Air Act Ammendments, many parts of which deal with motor vehicles. Motor vehicles are the primary source of urban carbon monoxide and are an important source of hydrocarbons and oxides of nitrogen responsible for the formation of photochemical smog and ground-level ozone. Cost estimates for implementing the Acts`s mobil source provisions range up to $12 billion annually. Because of the huge economic cost affecting a ubiquitous transportation method, the authors analyse the scientific basis for the legistation programs. Their work is described here. They conclude that regulatory policies based on a computer model that targets all vehicles equally, with out recognizing the overriding importance of individual maintenance, may not be cost-effective or may be ineffective. 23 refs., 1 fig., 1 tab.
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