Road Traffic Emissions Research Articles

Quantifying metal emissions from vehicular traffic using real world emission factors.

Road traffic emissions are an increasingly important source of particulate matter in urban and non-road environments, where non-tailpipe emissions can contribute substantially to elevated levels of metals associated with adverse health effects. Thus, better characterization and quantification of traffic-emitted metals is warranted. In this study, real-world emission factors for fine particulate metals were determined from hourly x-ray fluorescence measurements over a three-year period (2015-2018) at an urban roadway and busy highway. Inter-site differences and temporal trends in real-world emission factors for metals were explored. The emission factors at both sites were within the range of past studies, and it was found that Ti, Fe, Cu, and Ba emissions were 2.2-3.0 times higher at the highway site, consistent with the higher proportion of heavy-duty vehicles. Weekday emission factors for some metals were also higher by 2.0-3.5 times relative to Sundays for Mn, Zn, Ca, and Fe, illustrating a dependence on fleet composition and roadway activity. Metal emission factors were also inversely related to relative humidity and precipitation, due to reduced road dust resuspension under wetter conditions. Correlation analysis revealed groups of metals that were co-emitted by different traffic activities and sources. Determining emission factors enabled the isolation of traffic-related metal emissions and also revealed that human exposure to metals in ambient air can vary substantially both temporally and spatially depending on fleet composition and traffic volume.

Comparative toxicity of ultrafine particles around a major airport in human bronchial epithelial (Calu-3) cell model at the air–liquid interface

Relatively high concentrations of ultrafine particles (UFPs) have been observed around airports, in which aviation and road traffic emissions are the major sources. This raises concerns about the potential health impacts of airport UFPs, particularly in comparison to those emitted by road traffic. UFPs mainly derived from aviation or road traffic emissions were collected from a location near a major international airport, Amsterdam-Schiphol airport (AMS), depending on the wind direction, along with UFPs from an aircraft turbine engine at low and full thrust. Human bronchial epithelial cells (Calu-3) model in combination with an air-liquid interface (ALI) cloud system was used for the in vitro exposure to UFPs at low doses ranging from 0.09 to 2.07 μg/cm2. Particle size distribution was measured. Cell viability, cytotoxicity and inflammatory potential (interleukin (IL) 6 and 8 secretion) on Calu-3 cells were assessed after exposure for 24 h. The biological measurements on Calu-3 cells confirm that pro-inflammatory responses still can be activated at the high cell viability (> 80%) and low cytotoxicity. By the Benchmark Dose (BMD) analysis, Airport and Non-Airport (road traffic) UFPs as well as UFPs samples from a turbine engine have similar toxic properties. Our results suggest that UFPs from aviation and road traffic in airport surroundings may have similar adverse effects on public health.

Biomonitoring of metal levels in urban areas with different vehicular traffic intensity by using Araucaria heterophylla needles

For the first time, Araucaria heterophylla needles were used as a biomonitor to assess the concentration of metals in urban areas. The samples were collected in the Andean city Quito, in Ecuador, from sites with high, moderate and low vehicular traffic intensity. Then, the concentrations of Ca, K, Mg, Mn, Fe, Al, Ba, Zn, Cu, Cr, Pb and Co were measured by using an Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). Source apportionment was studied employing Principal Component (PCA) and Pearson analyses. Ca, K, and Mg were identified to come from natural sources, showing the highest levels. On the other hand, Mn, Fe and Al were related to both natural and road traffic emissions, while Ba, Zn, Cu, Cr, Pb and Co were only related to road traffic emissions. The decelerating activities were identified as the main source for vehicle non-exhaust emissions in the area of study. Areas with the highest vulnerability in metal emissions from vehicular traffic in the city of Quito were also identified through Geographic Information System. Alarming concentrations of traffic-related metals near a pediatric hospital were revealed. It was observed that streets located near a green area such as urban park, even with high or moderate traffic intensity, may experience reduced concentrations of pollutants. This work showed that Araucaria heterophylla needles are suitable for monitoring metals associated with road traffic emissions in areas with different vehicular traffic intensity.

Mobile phone GPS data in urban customized bus: Dynamic line design and emission reduction potentials analysis

Customized Bus is a new mode of Internet-supported public transportation. It is regarded as one of the major strategies to reduce the usage of private cars and mitigate greenhouse gas emissions from road traffic. For a customized bus system, a dynamic bus line planning system based on the demand can largely improve the performance and promote the public acceptance of customized bus service. This paper introduces a method to generate planning suggestions for bus lines and stops based on massive demand data. A link network is generated from the input to represent the sharing route of the demand. With community detection, the link network is segmented into communities with similar travel routes. By examining the core-peripheral structure and matching the core part of communities with the road network, the customized bus lines are generated. Boarding and alighting hotspots are identified as the suggestion for customized bus stops. The methodology is tested by using mobile phone data in Tokyo. With the input of one-day sample, the algorithm can generate the result in approximately 1 min and extract 29 bus lines. According to the shape and spatial location of the bus lines, three types of bus lines serving different travel patterns are classified: radiation type lines, ring-type lines, and suburban lines. Analyzing the emission reduction potential of the extracted bus lines manifestes that bus line planning of the proposed method has the potential to relieve emission pressure on urban expressways and to reduce approximately 13% of road traffic emission.

Atmospheric particulate matter and potentially hazardous compounds around residential/road side soil in an urban area

Exposure to ambient coarse and fine particulate matter (PM10 and PM2.5) causes premature death worldwide due to the nature of their particle size. It contains potentially hazardous elements (PHEs) and polycyclic aromatic hydrocarbons (PAHs). This study aims to quantify the particulate matter (PM) loads on the surface of soil in twenty-five different locations including residential and roadside areas of an urban area in Northeast India. This study shows that the 24h mean concentration of PM (121 ± 49 μg/m3 for PM2.5 and 153 ± 45 μg/m3 for PM10) exceeded more than three times the WHO’s air quality standard limit for both PM2.5 (25 μg/m3) and PM10 (50 μg/m3) indicating poor air quality in the urban area during monsoon season. The health risk assessment of PAHs and PHEs including mutagenic or carcinogenic potency was observed to be higher as compared to other studies carried out on road traffic emissions in a similar type of urban area. This study also provides a brief database on the deposition of PM on the soil surfaces due to wet-deposition that would help to increase public awareness in such type of urban area for the control of PM pollution and further remediation.

Application of reduction scenarios on traffic-related NOx emissions in Trabzon, Turkey

Traffic-related emissions are the main sources of certain air pollutants that affect large number of people in many city centers. Because of this fact, quantification of traffic-related emissions and their dispersion modeling are required to determine human exposure to these pollutants. In this study, the most populated Ortahisar district of Trabzon, a city located in the Eastern Black Sea region of Turkey, was selected as the study area since high traffic density is known to be one of the major sources of air pollution in this district. Moreover, air quality measurement stations located close to major roads are available to provide experimental data for model validation. Traffic emission inventory for some pollutants (NOx, SO2, CO, PM and VOCs) was prepared. Considering that NOx is the most representative air pollutant of road traffic emissions, its inventory together with topographical properties and meteorological conditions were used in AERMOD dispersion model to calculate NOx concentrations at selected receptor points. For validation, model data were compared to measurement data by certain statistical tools. According to the model results, 10.1% of the population living in Ortahisar district was exposed to traffic-related NOx concentrations higher than the regulatory limit value. In the study, five different emission reduction scenarios were tested to observe the effects on the exposure levels. Model results indicated that the measures represented by these scenarios are capable of reducing exposure levels between 2.4 and 99.5 percent.

Contributions of traffic and shipping emissions to city-scale NOx and PM2.5 exposure in Hamburg

Abstract We investigated the contribution of road traffic and shipping related emissions of NO2 and PM2.5 to total air quality and annual mean population exposure in Hamburg 2012. For this purpose, we compiled a detailed emission inventory following SNAP categories focusing on the detailed representations of road traffic and shipping emissions. The emission inventory was applied to a global-to-local Chemistry Transport Model (CTM) system to simulate hourly NO2 and PM2.5 concentrations with a horizontal grid resolution of 500 m. To simulate urban-scale pollutant concentrations we used the coupled prognostic meteorological and chemistry transport model TAPM. The comparison of modelled to measured hourly values gives high correlation and small bias at urban and background stations but large underestimations of NO2 and PM2.5 at measurements stations near roads. Simulated contributions of road traffic emissions to annual mean concentrations of NO2 and PM2.5 is highest close to highways with relative contributions of 50% for NO2 and 40% for PM2.5. Nevertheless, the urban domain is widely affected by road traffic, especially in the city centre. Shipping impact focuses on the port and nearby industrial areas with contributions of up to 60% for NO2 and 40% for PM2.5. In residential areas in the north of the port, shipping contributes with up to 20–30% for NO2 and PM2.5. Our simulation resulted in 14% of the population of Hamburg being exposed to hourly NO2 concentration above the hourly limit of 200 μg/m³,

Atmospheric pollution revealed by trace elements in recent snow from the central to the northern Tibetan Plateau

In order to determine the current levels, spatial distribution patterns, and potential pollution of trace elements (TEs) in the atmosphere of the Tibetan Plateau (TP), snow pit samples were collected in May 2016 from five TP glaciers: Qiyi (QY), Hariqin (HRQ), Meikuang (MK), Yuzhufeng (YZF), and Xiaodongkemadi (XDKMD). Concentrations of 13 TEs (Al, Ba, Cd, Co, Cr, Cu, Fe, Li, Pb, Sb, Sr, U, and Zn) in the snow were measured. The spatial distribution patterns and depth profiles of TEs from the studies sites revealed that the influence of dust on TEs was more significant on the MK and YZF glaciers than on the QY, HRQ, and XDKMD glaciers. The spatial distributions of TE EFFe values differed from their concentrations, however. The enrichment factor (EF) values and concentrations of some TEs in the YZF, QY, and XDKMD glaciers revealed that the pollution levels of these elements were significantly lower than those found in previous research. Examination based on EFs, principal component analysis, as well as the calculated non-dust contributions of TEs, revealed that dust was the principal source for most TEs in all five glaciers, while biomass burning was another potential natural source for TEs in some glaciers, such as QY. In contrast, Cd, Ba, Sr, Cu, Pb, Zn, and Sb were occasionally affected by anthropogenic sources such as road traffic emissions, fossil fuel combustion, and mining and smelting of nonferrous metals in and beyond the TP. Air mass backward trajectories revealed that potential pollutants were transported not only from local sources but also from Xinjiang Province in northwestern China, as well as South Asia, Central Asia, the Middle East, and Europe.

Selected Metals in Urban Road Dust: Upper and Lower Silesia Case Study

In this study, urban road dust (URD) samples were collected in two populated agglomerations of Wrocław and Katowice (Lower and Upper Silesia) in Poland. Both the total concentrations of URD-bound Mn, Ni, Cu, Zn, As, Rb, Ba, Cr, Mg, and Al and concentrations of their water-soluble fraction were determined. The contamination characteristics and health risk related to these elements were assessed. Contamination level assessment was done by Pollution Load Index (PLI), which indicated much higher pollution of Katowice agglomeration than Wrocław. The enrichment factor values (EF) showed that the most elements in both Katowice and Wrocław orginated from anthropogenic sources. The calculations of geo-accumulation index (Igeo) showed that Zn and As are the key pollutants in Katowice; and in the Wrocław region, Cu, Zn, Cr, and Ni are. The principle component analysis (PCA) and correlation analysis provide information about the potential sources of metals. Additionally, a positive matrix factorization (PMF) was performed and four factors in PMF analysis were found and then interpreted by comparing to the source profiles. Three contamination sources were revealed: fossil fuel combustion, road traffic and industrial emissions. Although the main source of studied metals in Lower Silesia is road traffic, in Upper Silesia, domestic heating with the use of hard and brawn coal and industrial activity predominates. Human exposure to individual toxic metals through road dust was assessed for both children and adults. By calculating the average daily dose (ADD) via ingestion, inhalation, and dermal contact, it was found that ingestion and then dermal contact were the greatest exposure pathways for humans in Katowice and Wrocław. Children had greater health risks than adults. According to the health risk assessment, the overall non-carcinogenic risks in both urban areas was rather low. The only exception was As bound to urban road dust in Katowice agglomeration, which indicates risk for children when ingested. The total excess cancer risk (ECR) was also lower than the acceptable level (10−6–10−4) for both adults and children, although ECR for Katowice was closer to this limit.

Integrating Modes of Transport in a Dynamic Modelling Approach to Evaluate Population Exposure to Ambient NO2 and PM2.5 Pollution in Urban Areas.

To evaluate the effectiveness of alternative policies and measures to reduce air pollution effects on urban citizen’s health, population exposure assessments are needed. Due to road traffic emissions being a major source of emissions and exposure in European cities, it is necessary to account for differentiated transport environments in population dynamics for exposure studies. In this study, we applied a modelling system to evaluate population exposure in the urban area of Hamburg in 2016. The modeling system consists of an urban-scale chemistry transport model to account for ambient air pollutant concentrations and a dynamic time-microenvironment-activity (TMA) approach, which accounts for population dynamics in different environments as well as for infiltration of outdoor to indoor air pollution. We integrated different modes of transport in the TMA approach to improve population exposure assessments in transport environments. The newly developed approach reports 12% more total exposure to NO2 and 19% more to PM2.5 compared with exposure estimates based on residential addresses. During the time people spend in different transport environments, the in-car environment contributes with 40% and 33% to the annual sum of exposure to NO2 and PM2.5, in the walking environment with 26% and 30%, in the cycling environment with 15% and 17% and other environments (buses, subway, suburban, and regional trains) with less than 10% respectively. The relative contribution of road traffic emissions to population exposure is highest in the in-car environment (57% for NO2 and 15% for PM2.5). Results for population-weighted exposure revealed exposure to PM2.5 concentrations above the WHO AQG limit value in the cycling environment. Uncertainties for the exposure contributions arising from emissions and infiltration from outdoor to indoor pollutant concentrations range from −12% to +7% for NO2 and PM2.5. The developed “dynamic transport approach” is integrated in a computationally efficient exposure model, which is generally applicable in European urban areas. The presented methodology is promoted for use in urban mobility planning, e.g., to investigate on policy-driven changes in modal split and their combined effect on emissions, population activity and population exposure.

Soluble Inorganic Arsenic Species in Atmospheric Submicron Particles in Two Polish Urban Background Sites

This paper presents results of the research on soluble inorganic As(III) and As(V) bound to submicron atmospheric particles (PM1) in two Polish urban background sites (Zabrze and Warsaw). The purpose of the research was to give some insight on the susceptibility to leaching of PM1-bound arsenic species from easily water-soluble compounds, i.e., considered potentially bioavailable based on its daily and seasonal changes. Quantitative analysis for 120 PM1 samples (collected from 24 June 2014 to 8 March 2015) was performed by using a high-performance liquid chromatography in combination with inductively coupled plasma mass spectrometry. The mean seasonal concentrations of dominant soluble As specie—As(V)—ranged from 0.27 ng/m3 in the summer season in Warsaw to 2.41 ng/m3 in the winter season in Zabrze. Its mean mass shares in total As were 44% in Warsaw and 75% in Zabrze in the winter and 18% and 48%, respectively, in the summer. Obtained results indicated fossil fuel combustion as the main source of PM1-bound As(V) and road traffic emission as its minor sources. In opposite to As(V), soluble As(III) was not clearly seasonally variable. In both seasons, its mean concentrations were higher in Zabrze than in Warsaw. As(III) concentrations were not preferentially shaped by an exact emission from road traffic in both cities.

A very high-resolution assessment and modelling of urban air quality

Abstract. Urban air quality is one of the most prominent environmental concerns for modern city residents and authorities. Accurate monitoring of air quality is difficult due to intrinsic urban landscape heterogeneity and superposition of multiple polluting sources. Existing approaches often do not provide the necessary spatial details and peak concentrations of pollutants, especially at larger distances from monitoring stations. A more advanced integrated approach is needed. This study presents a very high-resolution air quality assessment with the Parallelized Large-Eddy Simulation Model (PALM), capitalising on local measurements. This fully three-dimensional primitive-equation hydrodynamical model resolves both structural details of the complex urban surface and turbulent eddies larger than 10 m in size. We ran a set of 27 meteorological weather scenarios in order to assess the dispersion of pollutants in Bergen, a middle-sized Norwegian city embedded in a coastal valley. This set of scenarios represents typically observed weather conditions with high air pollution from nitrogen dioxide (NO2) and particulate matter (PM2.5). The modelling methodology helped to identify pathways and patterns of air pollution caused by the three main local air pollution sources in the city. These are road vehicle traffic, domestic house heating with wood-burning fireplaces and ships docked in the harbour area next to the city centre. The study produced vulnerability maps, highlighting the most impacted districts for each weather and emission scenario. Overall, the largest contribution to air pollution over inhabited areas in Bergen was caused by road traffic emissions for NO2 and wood-burning fireplaces for PM2.5 pollution. The effect of emission from ships in the port was mostly restricted to the areas close to the harbour and moderate in comparison. However, the results have contributed to implementation of measures to reduce emissions from ships in Bergen harbour, including provision of shore power.

Health effects of PM2.5 emissions from on-road vehicles during weekdays and weekends in Beijing, China

Mobile source emissions have significantly contributed to fine particulate matter (PM2.5) pollution in urban atmospheric environments. Few studies have explored on-road vehicular PM2.5 emissions and the health effects attributed to these emissions under different traffic conditions. Based on driving data obtained from 20000 taxi receipts, a motor vehicle emission simulator (MOVES) model was used to estimate the PM2.5 emission levels of motor vehicles in the urban area within the Sixth Ring Road of Beijing (SRRB) on weekdays and weekends, respectively. Two different PM2.5 exposure scenarios were further simulated using an atmospheric dispersion model. Subsequently, the health effects attributable to traffic-related PM2.5 exposure were quantified by using exposure-response function to calculate the population acute morbidity and premature mortality during different time periods. We found that PM2.5 emission levels of motor vehicles on normal weekdays were overall higher than those on weekends. The median vehicular PM2.5 dispersion concentration in the study area was 2.68 μg/m3 on weekdays and 1.82 μg/m3 on weekends. Annually, there were 4435 premature deaths attributed to vehicle emissions (95% confidence interval (CI): 3655, 4904) under weekday exposure conditions, and this number sharply decreased to 3462 (95% CI: 3052, 4011) on weekends. Considering the hourly measurements, road traffic emissions have the greatest impact on public health during morning rush hour (8:00 a.m.). Total PM2.5 emissions were closely associated with road traffic conditions and largely determined the magnitude of the health impacts caused by traffic-related PM2.5 exposure. These findings provide information to aid in formulating reasonable public health policies to address vehicular PM2.5 emission-induced health implications.

Quantifying road traffic emissions embedded in a multi-objective traffic assignment model

In a road network, drivers typically seek to minimize their own travel time, often affecting system-wide performance. With the increasing environmental awareness, for an efficient traffic assignment (TA), besides concerns with travel times, traffic managers should not neglect the system-wide level of both global and local pollutant emissions. Measuring road traffic emissions can be costly and different models based on vehicle-specific parameters with many input variables have been suggested in the literature. This paper proposes a simple way to quantifying carbon dioxide (CO2) and nitrogen oxides (NOX) emissions with only average speed as input variable and presents a multi-objective TA approach that seeks to minimize system-wide travel time, distance travelled (associated with fuel consumption) and global and local pollutant emissions. A real-world case study on an intercity corridor with many alternative routes between two zones is presented. Experiments considering TA based on travel time, and on time, distance travelled, and pollutant emissions are reported. Results highlight that system optimal distribution based on the suggested multi-objective TA based on three components yields savings in terms of distance travelled (2.6%) and emissions (1.3% for CO2 and 1.1% for NOX), but penalizes travel time 3%, which is translated in an increase of 20sec per vehicle, when compared to the solution only focused on minimizing travel time. The developed methodology is a suitable tool for traffic analysts to predict vehicle system-wide travel time, distance travelled and pollutant emissions with few vehicle information but with a reasonable detail for a specific traffic flow on a given road network, to support analyses for sustainable transport policies and may be used, for instance, as an environmental impact component of a pricing scheme, traffic signal control strategies based on emissions reduction, or to minimize congestion by giving prior information to drivers on the specific routes to be chosen.

Monsoon Season Quantitative Assessment of Biomass Burning Clear-Sky Aerosol Radiative Effect at Surface by Ground-Based Lidar Observations in Pulau Pinang, Malaysia in 2014

Direct and indirect aerosol effects are still one of the largest uncertainties related to the Earth energy budget, especially in a wild and remote region like South-East Asia, where ground-based measurements are still difficult and scarce, while endemic cloudy skies make difficult active and passive satellite observations. In this preliminary study, we analyzed and quantitatively assessed the differences between monsoon and inter-monsoon seasons, in terms of radiative effects at surface and columnar heating rate, of clear-sky biomass burning aerosols (no clouds) using ground-based lidar observations obtained with a 355 nm elastic lidar instrument, deployed since 2012 at the Physics Department of Universiti Sains Malaysia (USM). The model-based back-trajectory analysis put in evidence that, during the monsoon seasons (November–March and June–September), the air masses advected towards the observational site transit over active fire hotspot regions, in contrast with the inter-monsoon season. In between the monsoon seasons (April–May, October), the atmosphere over Penang is constituted by local background urban aerosols that originate from road traffic emissions, domestic cooking, and industrial plants emissions. The analysis was carried out using the vertically-resolved profiles of the seasonal averaged aerosol optical properties (monsoon vs. inter-monsoon seasons), e.g., the atmospheric extinction coefficient, to evaluate the seasonal surface aerosol radiative effect and column heating rate differences through the Fu–Liou–Gu (FLG) radiative transfer model. The results put in evidence that the biomass burning advection during the monsoon season (especially during the South West monsoon from June to September) lowers the noon daytime incoming solar shortwave solar radiation reaching the Earth surface with respect to the local background conditions by 91.5 W/m2 (114–69 W/m2). The aerosols also lead to an averaged heating in the first kilometer of the atmosphere of about 4.9 K/day (6.4–3.4 W/m2). The two combined effects, i.e., less absorbed energy by Earth surface and warming of the first kilometer of the boundary layer, increase the low-level stability during monsoon seasons, with a possible reduction in cloud formation and precipitation. The net effect is to exacerbate the haze episodes, as the pollutants rest trapped into the boundary layer. Besides these considerations, the lidar measurements are of great interest in this particular world region and might be used for cal/val of the future space missions, e. g., Earthcare.

Associations between metal constituents of ambient particulate matter and mortality in England: an ecological study

ObjectivesTo investigate long-term associations between metal components of particulate matter (PM) and mortality and lung cancer incidence.DesignSmall area (ecological) study.SettingPopulation living in all wards (~9000 individuals per ward) in the...

Combined NOx and noise pollution from road traffic in Trabzon, Turkey

Environmental impacts of motor vehicles in the form of air and noise pollution have attracted more interest in recent years due to their relation with some health problems such as asthma, bronchitis, cardiovascular disease, myocardial infarction, and hypertension. Recently, it has been suggested that not only their individual effects but also their combined effects should be considered in public health studies. In this study, NOx and noise pollution levels were determined in Trabzon, a city in the Eastern Black Sea region of Turkey. For this purpose, a traffic emission inventory was prepared to be used in an air pollution modeling software to determine the concentrations of NOx, one of the primary pollutants from road traffic emissions, within the study area. Also, vehicle counts and types were determined to be used in noise pollution software to evaluate the noise pollution levels in the study area. Model results were compared to measurement data by using different statistical tools. Separate and combined exposures of the population to traffic-related NOx and noise emissions were examined together with meteorological and topographic effects on them. The relationship between NOx and noise pollution indicated that, they are highly correlated in two districts (Valilik and Meydan) out of the four examined in Trabzon city center, suggesting traffic is the dominant source for both. Results indicated that percentages of the population exposed to traffic-related NOx and noise levels above the regulatory limits were 10% and 21%, respectively. It was determined that 6% of the population, 29 school and 19 hospital buildings were exposed to both noise and NOx levels above the regulatory limits in the city center of Trabzon. These percentages should be considered as conservative since additional NOx and noise sources other than traffic might increase the exposure levels of the population.

Emissions vs exposure: Increasing injustice from road traffic-related air pollution in the United Kingdom

This paper presents unique spatial analyses identifying substantial discrepancies in traffic-related emissions generation and exposure by socioeconomic and demographic groups. It demonstrates a compelling environmental and social injustice narrative with strong policy implications for the UK and beyond.In the first instance, this research presents a decadal update for England and Wales to Mitchell and Dorling’s 2003 analysis of environmental justice in the UK. Using 2011 UK Government pollution and emissions data with 2011 UK Census socioeconomic and demographic data based on small area census geographies, this paper demonstrates a stronger relationship between age, poverty, road NOx emissions and exposure to NO2 concentrations. Areas with the highest proportions of under-fives and young adults, and poorer households, have the highest concentrations of traffic-related pollution.In addition, exclusive access to UK annual vehicle safety inspection records (‘MOT’ tests) allowed annual private vehicle NOx emissions to be spatially attributed to registered keepers. Areal analysis against Census-based socioeconomic characteristics identified that households in the poorest areas emit the least NOx and PM, whilst the least poor areas emitted the highest, per km, vehicle emissions per household through having higher vehicle ownership, owning more diesel vehicles and driving further.In conclusion, the analysis indicates that, despite more than a decade of air quality policy, environmental injustice of air pollution exposure has worsened. New evidence regarding the responsibility for generation of road traffic emissions provides a clear focus for policy development and targeted implementation.

Estimation of emissions of air pollutants in the Krapina-Zagorje county

The Program for the protection of air quality, ozone layer, climate change mitigation and adaptation of the Krapina-Zagorje County is prepared in accordance with the Article 12 of the Air Protection Act (OG 130/11, 47/14, 61/17, 118/18). The Program sets targets and measures by priority sectors, deadlines and responsible authorities for measures implementation over a five-year period in the County. For the purpose of defining protection measures, based on available data, estimation of annual emissions of pollutants into air was performed: nitrogen oxides, carbon monoxide, sulphur oxides, particles, volatile organic compounds, ammonia, carbon dioxide, methane and dinitrogen monoxide from the main sectors. Emissions were estimated using the EMEP/EEA methodology and 2006 IPCC Guidelines for National Greenhouse Gas Inventories methodology. Road traffic emissions were estimated using DEFRA/DECC methodology. Based on the results on estimated pollutant emissions in the County, appropriate measures have been defined for the protection and improvement of air quality.

Development of a road traffic emission inventory with high spatial-temporal resolution in the world's most densely populated region-Macau.

With rapid economic growth, road transport is contributing substantial adverse effects on urban air quality, especially in densely populated cities with high growth rate of GDP per capita, such as Macau. A high spatial-temporal resolution road traffic emission inventory is essential for assessment of environmental stresses imposed by local vehicle movements. To improve the accuracy and temporal-spatial resolution for emission inventory, through a bottom-up approach, link-based road traffic emission inventory with a spatial resolution of 0.1km∗0.1km and a temporal resolution of 1h for Macau in 2014 was developed by using a traffic model (VISUM), a road traffic emission model (TREM), the Geographic Information System (GIS), and the most up-to-date information available. Results show that the total annual emissions of CO, CO2, PM, NOX, and VOC in 2014 were 14,770, 413,099, 69, 1151, and 2945tons, respectively. The estimated fuel consumption agreed well also with the statistical fuel consumption in Macau. Meanwhile, analysis of 3 scenarios on changes of road traffic emissions due to the operation of a light railway transit (LRT) system, variation on share of diesel, electric, and gasoline within the vehicle fleet, and replacement of vehicles with ones of Euro 5 and Euro 6 emission standards was carried out. This study provides a solid framework for developing high spatial-temporal resolution emission inventories for other densely populated cities of small area.