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Abstract Regulations, definitions, and calculations related to emissions of Volatile Organic Compounds (VOC) from paints used for horizontal road markings (traffic paints) in North America and in European Union are different, which frequently makes simple comparisons impossible. To illustrate the dissimilarities, solvent packages of various exemplary paints that meet several normative requirements were compared for the nominal emissions according to different calculation procedures. For a unified assessment, volatile portions of the paints were evaluated based on Ozone Formation Potential (OFP). The analysis revealed that similar nominal VOC contents can lead to vastly different OFP, in an extreme case six times higher. Incongruously high OFP, which was calculated for emissions in Southern California despite strict limits can thus be explained. The provided calculations can be used by road administrators as a tool to demand materials with lowest environmental impact, by environmental researchers to pinpoint irregularities between declared and measured discharges, and can assist formulating chemists in selection of raw materials to prepare environmentally friendly road marking paints. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Air quality has significantly improved in Europe over the past few decades. Nonetheless we still find high concentrations in measurements mainly in specific regions or cities. This dimensional shift, from EU-wide to hot-spot exceedances, calls for a novel approach to regional air quality management (to complement EU-wide existing policies). The SHERPA (Screening for High Emission Reduction Potentials on Air quality) modelling tool was developed in this context. It provides an additional tool to be used in support to regional/local decision makers responsible for the design of air quality plans. It is therefore important to evaluate the quality of the SHERPA model, and its behavior in the face of various kinds of uncertainty. Uncertainty and sensitivity analysis techniques can be used for this purpose. They both reveal the links between assumptions and forecasts, help in-model simplification and may highlight unexpected relationships between inputs and outputs. Thus, a policy steered SHERPA module - predicting air quality improvement linked to emission reduction scenarios - was evaluated by means of (1) uncertainty analysis (UA) to quantify uncertainty in the model output, and (2) by sensitivity analysis (SA) to identify the most influential input sources of this uncertainty. The results of this study provide relevant information about the key variables driving the SHERPA output uncertainty, and advise policy-makers and modellers where to place their efforts for an improved decision-making process. [ABSTRACT FROM AUTHOR]

Air quality standards for settleable particulate matter (SPM) are found in many countries around the world. As well known, annoyance caused by SPM can be considered a community problem even if only a small proportion of the population is bothered at rather infrequent occasions. Many authors have shown that SPM cause soiling in residential and urban environments and degradation of materials (eg, objects and surface painting) that can impair the use and enjoyment of property and alter the normal activities of society. In this context, this paper has as main contribution to propose a guidance to establish air quality standards for annoyance caused by SPM in metropolitan industrial areas. To attain this objective, a new methodology is proposed which is based on the nonlinear correlation between the perceived annoyance (qualitative variable) and particles deposition rate (quantitative variable). Since the response variable is binary (annoyed and not annoyed), the logistic regression model is used to estimate the probability of people being annoyed at different levels of particles deposition rate and to compute the odds ratio function which gives, under a specific level of particles deposition rate, the estimated expected value of the population perceived annoyance. The proposed methodology is verified in a data set measured in the metropolitan area of Great Vitória, Espirito Santo, Brazil. As a general conclusion, the estimated probability function of perceived annoyance as a function of SPM has shown that 17% of inhabitants report annoyance to very low particles deposition levels of 5 g/(m 2 ∙30 days). In addition, for an increasing of 1 g/(m 2 ∙30 days) of SPM, the smallest estimated odds ratio of perceived annoyance by a factor of 1.5, implying that the probability of occurrence is almost 2 times as large as the probability of no occurrence of annoyance. [ABSTRACT FROM AUTHOR]

Season-long methane ( CH 4 ) exchange was observed in a rice paddy field in central Japan (Kanto Region) using the eddy covariance technique to clarify the variations in environmental controls on CH 4 exchange in different stages of cultivation. Before heading of rice plant, the CH 4 emission depended on wind speed and soil temperature. The soil temperature dependence can be due to an increase in CH 4 production, higher molecular diffusion, and higher conductance within rice plant at higher soil temperature. An occurrence of ebullitive emission was also suggested from the wind speed dependence. After heading was completed, relative humidity and water temperature influenced CH 4 emission. The amplitude of the diurnal variation in emission increased from 0.03 μ mol m − 2 s − 1 in the late pre-heading stage to 0.13 μ mol m − 2 s − 1 in the post-heading stage. Induced convective throughflow within the rice aerenchyma after the change in plant structure was attributable to this variation in environmental controls after the heading. After drainage, CH 4 emission was confined to short periods after strong rain events. The water level controlled the timing of emission, most likely by influencing the diffusion efficiency from the anoxic soil to the atmosphere and CH 4 oxidation in the surface oxic zone. The variation in the dominant transport pathway needs to be accounted for in terrestrial ecosystem models to accurately predict CH 4 emission from rice paddies. [ABSTRACT FROM AUTHOR]

Black carbon mitigation has received increasing attention for its potential contribution to both climate change mitigation and air pollution control. Although different bottom-up models concerned with unit mitigation costs of various technologies allow the assessment of alternative policies for optimized cost-effectiveness, the lack of adequate data often forced many reluctant explicit and implicit assumptions that deviate away from actual situations of rural residential energy consumption in developing countries, where most black carbon emissions occur. To gauge the theory-practice gap in black carbon mitigation – the unit cost differences that lie between what is estimated in the theory and what is practically achieved on the ground – this study conducted an extensive field survey and analysis of nine mitigation technologies in rural China, covering both northern and southern regions with different residential energy consumption patterns. With a special focus on two temporal characteristics of those technologies – lifetimes and annual utilization rates, this study quantitatively measured the unit cost gaps and explain the technical as well as sociopolitical mechanisms behind. Structural and behavioral barriers, which have affected the technologies’ performance, are discussed together with policy implications to narrow those gaps. [ABSTRACT FROM AUTHOR]

There is an ongoing debate regarding the influence of the source location of pollution on the fate of pollutants and their subsequent impacts. Several methods have been developed to derive site-dependent characterization factors (CFs) for use in life-cycle assessment (LCA). Consistent, precise, and accurate estimates of CFs are crucial for establishing long-term, sustainable air pollution abatement policies. We reviewed currently available studies on the regionalization of non-toxic air pollutants in LCA. We also extracted and converted data into indices for analysis. We showed that CFs can distinguish between emissions occurring in different locations, and that the different methods used to derive CFs map locations consistently from very sensitive to less sensitive. Seasonal variations are less important for the computation of CFs for acidification and eutrophication, but they are relevant for the calculation of CFs for tropospheric ozone formation. Large intra-country differences in estimated CFs suggest that an abatement policy relying on quantitative estimates based upon a single method may have undesirable outcomes. Within country differences in estimates of CFs for acidification and eutrophication are the results of the models used, category definitions, soil sensitivity factors, background emission concentration, critical loads database, and input data. Striking features in these studies were the lack of CFs for countries outside Europe, the USA, Japan, and Canada, the lack of quantification of uncertainties. Parameter and input data uncertainties are well quantified, but the uncertainty associated with the choice of category indicator is rarely quantified and this can be significant. Although CFs are scientifically robust, further refinements are needed before they can be integrated in LCA. Future research should include uncertainty analyses, and should develop a consensus model for CFs. CFs for countries outside Europe, Japan, Canada and the USA are urgently needed. [ABSTRACT FROM AUTHOR]

The world population is demonstrating an increasing awareness about the ecological impacts of air quality, including impacts on human health. The Veneto region and, more generally, the Po Valley (NE Italy), are characterised by frequent exceedance of limit values for air quality, in particular particulate matter (PM 10), which causes these areas to be listed as hotspots; thus, this region has some of the worst air pollution in Europe. The aim of the current research was to analyse a 10 year-long time series of air quality data (2011–2021) in the Veneto region to investigate the influence of selected factors on air quality, such as natural processes (meteorological conditions), environmental policies, and health emergency measures due to the COVID-19 pandemic. Generally, the considered pollutants, PM 10 , NO, and NO 2 , presented a decreasing trend during the last ten years. The reduction in nitrogen oxides was clearly improved after the implementation of a specific environmental protocol (the "New Agreement of Po Valley Basin"). Conversely, the PM 10 concentration seemed to be affected by other important emission sources, such as domestic heating systems, agricultural activities, and animal farms, which are not as strongly regulated as emission sources such as traffic. The 2020 lockdown mainly influenced nitrogen oxide concentrations. • Italy has infringed on the EU law regarding ambient air quality. • One of the more polluted Italian areas is the Po Valley, including the Veneto region. • A long time series of the air quality data region was statistically analysed. • Only nitrogen oxide concentrations were significantly reduced during the last ten years. • Environmental policies have mainly addressed traffic emissions. [ABSTRACT FROM AUTHOR]

Understanding the relationship between mobile source emissions and subsequent human exposure is crucial for emissions control. Determining this relationship over space is fundamental to improve the accuracy and precision of public policies. In this study, we evaluated the spatial patterns of link-based PM 2.5 emissions and subsequent human exposure in a large Canadian metropolitan area - the Greater Toronto and Hamilton Area (GTHA). This study was performed in three stages. First, we estimated vehicle emissions using transportation models and emission simulators. Then we evaluated human exposure to PM 2.5 emissions using the Intake fraction (iF) approach. Finally, we applied geostatistical methods to assess spatial patterns of vehicle emissions and subsequent human exposure based on three prospective goals: i) classification of emissions (Global Moran's I test), ii) level of emission exposure (Getis-Ord General G test), and; iii) location of emissions (Anselin Local Moran's I). Our results showed that passenger vehicles accounted for the highest total amount of PM 2.5 emissions, representing 57% emissions from all vehicles. Examining only the emissions from passenger vehicles, on average, each person in the GTHA inhales 2.58 × 10 −3 ppm per day. Accounting the emissions from buses and trucks, on average each person inhales 0.12 × 10 −3 and 1.91 × 10 −3 ppm per day, respectively. For both PM 2.5 emissions and human exposure using iF approach, our analysis showed Moran's Index greater than 0 for all vehicle categories, suggesting the presence of significant clusters (p-value <0.01) in the region. Our study indicates that air pollution control policy must be developed for the whole region, because of the spatial distribution of housing and businesses centers and inter-connectivity of transportation networks across the region, where a policy cannot simply be based on a municipal or other boundaries. [ABSTRACT FROM AUTHOR]

In recent years several European air pollution policies have been based on a cost-effectiveness approach. In the European Union, the European Commission starts using the multi-pollutant, multi-effect GAINS (Greenhouse Gas Air Pollution Interactions and Synergies) model to identify cost-effective National Emission Ceilings and specific emission control measures for each Member State to reach these targets. In this paper, we apply the GAINS methodology to the case of Italy with 20 subnational regions. We present regional results for different approaches to environmental target setting for PM2.5 pollution in the year 2030. We have obtained these results using optimization techniques consistent with those of GAINS-Europe, but at a higher resolution. Our results show that an overall health-impact oriented approach is more cost-effective than setting a nation-wide limit value on ambient air quality, such as the one set for the year 2030 by the European Directive on ambient air quality and cleaner air for Europe. The health-impact oriented approach implies additional emission control costs of 153 million €/yr on top of the baseline costs, compared to 322 million €/yr for attaining the nation-wide air quality limit. We provide insights into the distribution of costs and benefits for regions within Italy and identify the main beneficiaries of a health-impact approach over a limit-value approach. [ABSTRACT FROM AUTHOR]

In this paper, we present ten scenarios developed using the IMAGE2.4 framework (Integrated Model to Assess the Global Environment) to explore how different assumptions on future climate and air pollution policies influence emissions of greenhouse gases and air pollutants. These scenarios describe emission developments in 26 world regions for the 21st century, using a matrix of climate and air pollution policies. For climate policy, the study uses a baseline resulting in forcing levels slightly above RCP6.0 and an ambitious climate policy scenario similar to RCP2.6. For air pollution, the study explores increasingly tight emission standards, ranging from no improvement, current legislation and three variants assuming further improvements. For all pollutants, the results show that more stringent control policies are needed after 2030 to prevent a rise in emissions due to increased activities and further reduce emissions. The results also show that climate mitigation policies have the highest impact on SO 2 and NO X emissions, while their impact on BC and OC emissions is relatively low, determined by the overlap between greenhouse gas and air pollutant emission sources. Climate policy can have important co-benefits; a 10% decrease in global CO 2 emissions by 2100 leads to a decrease of SO 2 and NO X emissions by about 10% and 5%, respectively compared to 2005 levels. In most regions, low levels of air pollutant emissions can also be achieved by solely implementing stringent air pollution policies. The largest differences across the scenarios are found in Asia and other developing regions, where a combination of climate and air pollution policy is needed to bring air pollution levels below those of today. [ABSTRACT FROM AUTHOR]

Critical operations of chemical process industry (CPI) plants such as ethylene plant shutdowns could emit a huge amount of VOCs and NOx, which may result in localized and transient ozone pollution events. In this paper, a general methodology for studying dynamic ozone impacts associated with flare emissions from ethylene plant shutdowns has been developed. This multi-scale simulation study integrates process knowledge of plant shutdown emissions in terms of flow rate and speciation together with regional air-quality modeling to quantitatively investigate the sensitivity of ground-level ozone change due to an ethylene plant shutdown. The study shows the maximum hourly ozone increments can vary significantly by different plant locations and temporal factors including background ozone data and solar radiation intensity. It helps provide a cost-effective air-quality control strategy for industries by choosing the optimal starting time of plant shutdown operations in terms of minimizing the induced ozone impact (reduced from 34.1 ppb to 1.2 ppb in the performed case studies). This study provides valuable technical supports for both CPI and environmental policy makers on cost-effective air-quality controls in the future. [ABSTRACT FROM AUTHOR]

This study describes a new methodology to calculate Non-Methane Volatile Organic Compounds from Domestic Solvent Use including Fungicides over the period 1992–2014. Improved emissions data compiled at a much more refined level can help policy-makers develop more effective policy’s to address environmental issues. However, a number of problems were found when member states attempt to use national statistics for Domestic Solvent Use including Fungicides. For instance, EMEP/EEA (2013) provides no guidance regarding which activity data should be used, resulting in emission estimates being potentially inconsistent and un-comparable. Also, previous methods and emission factors described in the EMEP/EEA (2013) guidebook do not exactly match data collected by state agencies. This makes using national statistics difficult. In addition, EMEP/EEA (2013) use broader categories than necessary (e.g. Cosmetics Aerosol/Non Aerosol) to estimate emissions while activity data is available at a more refined level scale (e.g. Personal Cleaning Products, Hair Products, Cosmetics, Deodorants and Perfumes). This can make identifying the drivers of emissions unclear. This study builds upon Tzanidakis et al. (2012) whereby it provides a method for collecting activity data from state statistics, developed country specific emission factors based on a survey of 177 Irish products and importantly, used a new method to account for the volatility of organic compounds found in commonly available domestic solvent containing products. This is the first study to account for volatility based on the characteristics of organic compounds and therefore is considered a more accurate method of accounting for emissions from this emission source. The results of this study can also be used to provide a simple method for other member parties to account for the volatility of organic compounds using sectorial adjustment factors described here. For comparison purposes, emission estimates were calculated using the Tier 1 approach currently used in the emission inventory, using activity data and emission factors unadjusted for volatility and adjusted for volatility. The unadjusted estimate is useful, because it demonstrates the failure to properly account for volatility can produce significantly over-estimated emissions from the Domestic Solvent Usage sector. Unadjusted emissions were found to be 30% lower than the EMEP/EEA (2013) Tier 1 period in 2014. Emissions were found to reduce a further 20.9% when the volatility of the organic compounds was included. This new method shows that member parties may be significantly overestimating emissions from Domestic Solvent Use including pesticides and further work should include refining organic compound content and the sectorial adjustment factor of products. [ABSTRACT FROM AUTHOR]

To improve air quality, knowledge of the sources and locations of air pollutant emissions is critical. However, for many global cities, no previous estimates exist of how much exposure to fine particulate matter (PM 2.5), the largest environmental cause of mortality, is caused by emissions within the city vs. outside its boundaries. We use the Intervention Model for Air Pollution (InMAP) global-through-urban reduced complexity air quality model with a high-resolution, global inventory of pollutant emissions to quantify the contribution of emissions by source type and location for 96 global cities. Among these cities, we find that the fraction of PM 2.5 exposure caused by within-city emissions varies widely (μ = 37%; σ = 22%) and is not well-explained by surrounding population density. The list of most-important sources also varies by city. Compared to a more mechanistically detailed model, InMAP predicts urban measured concentrations with lower bias and error but also lower correlation. Predictive accuracy in urban areas is not particularly high with either model, suggesting an opportunity for improving global urban air emission inventories. We expect the results herein can be useful as a screening tool for policy options and, in the absence of available resources for further analysis, to inform policy action to improve public health. • The contributions of different air pollution sources vary widely among cities. • The contributions of within-city vs. external emission sources to a city's air pollution also varies widely among cities. • The contributions above cannot be accurately predicted without air quality modeling. • An opportunity exists to improve global emission inventories in urban areas. [ABSTRACT FROM AUTHOR]

A systematic dataset of an observation network on a national scale has been organized to investigate the spatial distribution of bulk sulfur (S) deposition (S dep ) throughout China during 2000–2013, representing by far the most detailed data set to track the bulk sulfur deposition throughout China since 2000. Such a dataset is needed for ecosystem studies and for developing emission control policies. Bulk S dep values showed great variations, ranging from 2.17 to 70.55 kg ha −1 y −1 , with an average of 22.99 kg ha −1 y −1 . The average rate of bulk S dep located in East Coastal region (35.97 kg ha −1 y −1 ), Middle Yangtze region (57.90 kg ha −1 y −1 ), Middle Yellow River region (23.42 kg ha −1 y −1 ), North Coastal region (42.19 kg ha −1 y −1 ), Northeast region (34.28 kg ha −1 y −1 ), South Coastal region (36.97 kg S ha −1 y −1 ), Southwest region (33.85 kg ha −1 y −1 ) was 4.50, 7.24, 2.93, 5.28, 4.29, 4.63 and 4.24 times than that in Northwest region (7.99 kg ha −1 y −1 ). Bulk S dep over China was mainly from fossil fuel combustion (76.96%), biomass burning (7.64%), crust (6.22%), aged sea salt (5.48%) and agriculture (3.68%). A systematic observation network on a national scale should be established to conduct a long-term monitoring atmospheric S dep (including wet and dry deposition), based on exiting ecological stations administrated by different departments in China. [ABSTRACT FROM AUTHOR]

Wollongong, Australia is an urban site at the intersection of anthropogenic, biomass burning, biogenic and marine sources of atmospheric trace gases. The location offers a valuable opportunity to study drivers of atmospheric composition in the Southern Hemisphere. Here, a record of surface carbon monoxide (CO), methane (CH 4 ) and carbon dioxide (CO 2 ) was measured with an in situ Fourier transform infrared trace gas analyser between April 2011 and August 2014. Clean air was found to arrive at Wollongong in approximately 10% of air masses. Biomass burning influence was evident in the average annual cycle of clean air CO during austral spring. A significant negative short-term trend was found in clean air CO (−1.5 nmol mol −1 a −1 ), driven by a reduction in northern Australian biomass burning. Significant short-term positive trends in clean air CH 4 (5.4 nmol mol −1 a −1 ) and CO 2 (1.9 μmol mol −1 a −1 ) were consistent with the long-term global average trends. Polluted Wollongong air was investigated using wind-direction/wind-speed clustering, which revealed major influence from local urban and industrial sources from the south. High values of CH 4 , with anthropogenic ΔCH 4 /ΔCO 2 enhancement ratio signatures, originated from the northwest, in the direction of local coal mining. A pollution climatology was developed for the region using back trajectory analysis and ΔO 3 /ΔCO enhancement ratios. Ozone production environments in austral spring and summer were associated with anticyclonic meteorology on the east coast of Australia, while ozone depletion environments in autumn and winter were associated with continental transport, or fast moving trajectories from southern latitudes. This implies the need to consider meteorological conditions when developing policies for controlling air quality. [ABSTRACT FROM AUTHOR]

An extremely severe and persistent haze event occurred over the middle and eastern China in January 2013, with the record-breaking high concentrations of fine particulate matter (PM 2.5 ). In this study, an online-coupled meteorology-air quality model, the Weather Research and Forecasting Model with Chemistry (WRF/Chem), is applied to simulate this pollution episode over East Asia and northern China at 36- and 12-km grid resolutions. A number of simulations are conducted to examine the sensitivities of the model predictions to various physical schemes. The results show that all simulations give similar predictions for temperature, wind speed, wind direction, and humidity, but large variations exist in the prediction for precipitation. The concentrations of PM 2.5 , particulate matter with aerodynamic diameter of 10 μm or less (PM 10 ), sulfur dioxide (SO 2 ), and nitrogen dioxide (NO 2 ) are overpredicted partially due to the lack of wet scavenging by the chemistry-aerosol option with the 1999 version of the Statewide Air Pollution Research Center (SAPRC-99) mechanism with the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) and the Volatility Basis Set (VBS) for secondary organic aerosol formation. The optimal set of configurations with the best performance is the simulation with the Gorddard shortwave and RRTM longwave radiation schemes, the Purdue Lin microphysics scheme, the Kain-Fritsch cumulus scheme, and a nudging coefficient of 1 × 10 −5 for water vapor mixing ratio. The emission sensitivity simulations show that the PM 2.5 concentrations are most sensitive to nitrogen oxide (NO x ) and SO 2 emissions in northern China, but to NO x and ammonia (NH 3 ) emissions in southern China. 30% NO x emission reductions may result in an increase in PM 2.5 concentrations in northern China because of the NH 3 -rich and volatile organic compound (VOC) limited conditions over this area. VOC emission reductions will lead to a decrease in PM 2.5 concentrations in eastern China. However, 30% reductions in the emissions of SO 2 , NO x , NH 3 , and VOC, individually or collectively, are insufficient to effectively mitigate the severe pollution over northern China. More aggressive emission controls, which needs to be identified in further studies, are needed in this area to reach the objective of 25% PM 2.5 concentration reduction in 2017 proposed in the Action Plan for Air Pollution Prevention and Control by the State Council in 2013. [ABSTRACT FROM AUTHOR]

Air pollution levels within Lisbon city limits have been exceeding the limit values established in European Union and national legislation since 2001, with the most problematic cases related to the levels of fine particles (PM 10 ) and nitrogen dioxide (NO 2 ), mainly originated by road traffic. With the objective of answering this public health issue, an Air Quality Action Plan was developed in 2006 and the respective Enforcement Plan was published in 2009. From the overall strategy, one of the major measures presented in this strategy was the creation of a Low Emission Zone (LEZ) in Lisbon, which has been operating since July 2011. Implemented at different stages it has progressively expanded its area, including more vehicle types and adopting more stringent requirements in terms of minimum emission standards (currently LEZ phase 2 with EURO 2 in the city center – zone 1 and EURO 1 in the rest of the LEZ area – zone 2). At the same time the road axis comprised of Marquês de Pombal square and Avenida da Liberdade was subjected to profound changes in its traffic circulation model, reducing road traffic volumes. The analysis of the air quality data before and after the LEZ phase 2 has shown positive evolution when comparing the period between 2011 (before measures) and 2013 (after measures). In 2013, there was a reduction in PM 10 annual average concentration of 23% and NO 2 annual average concentrations of 12%, compared with the year 2011. Although PM 10 reductions were more significant inside the LEZ area, the same was not valid for NO 2 , suggesting that the implementation of these measures was not as effective in reducing NO 2 levels as shown by results in other cities like Berlin and London. The results from road traffic characterization indicate a relevant effect on fleet renewal with an overall decrease in the relative weight of pre-EURO 2 vehicles in 2012/2013, compared with data from 2011. An important increase in the share of EURO 4 and EURO 5 vehicles was also observed. Our conclusions show that the level of ambition is relevant for the observed effects. Therefore, stricter restriction standards should be enforced in the future stages of the Lisbon LEZ in conjunction with a higher effort and investment on LEZ enforcement. [ABSTRACT FROM AUTHOR]

For reducing health impacts from air pollution, it is important to know the sources contributing to human exposure. This study systematically reviewed and analysed available source apportionment studies on particulate matter (of diameter of 10 and 2.5 microns, PM 10 and PM 2.5 ) performed in cities to estimate typical shares of the sources of pollution by country and by region. A database with city source apportionment records, estimated with the use of receptor models, was also developed and available at the website of the World Health Organization. Systematic Scopus and Google searches were performed to retrieve city studies of source apportionment for particulate matter. Six source categories were defined. Country and regional averages of source apportionment were estimated based on city population weighting. A total of 419 source apportionment records from studies conducted in cities of 51 countries were used to calculate regional averages of sources of ambient particulate matter. Based on the available information, globally 25% of urban ambient air pollution from PM 2.5 is contributed by traffic, 15% by industrial activities, 20% by domestic fuel burning, 22% from unspecified sources of human origin, and 18% from natural dust and salt. The available source apportionment records exhibit, however, important heterogeneities in assessed source categories and incompleteness in certain countries/regions. Traffic is one important contributor to ambient PM in cities. To reduce air pollution in cities and the substantial disease burden it causes, solutions to sustainably reduce ambient PM from traffic, industrial activities and biomass burning should urgently be sought. However, further efforts are required to improve data availability and evaluation, and possibly to combine with other types of information in view of increasing usefulness for policy making. [ABSTRACT FROM AUTHOR]

A total of 13 diesel buses and 12 diesel trucks in Macao were tested using portable emission measurement systems (PEMS) including a SEMTECH-DS for gaseous emissions and a SEMTECH-PPMD for PM 2.5 . The average emission rates of gaseous pollutants and CO 2 are developed with the operating mode defined by the instantaneous vehicle specific power (VSP) and vehicle speed. Both distance-based and fuel mass-based emission factors for gaseous pollutants (e.g., CO, THC and NO X ) are further estimated under typical driving conditions. The average distance-based NO X emission of heavy-duty buses (HDBs) is higher than 13 g km −1 . Considering the unfavorable conditions for selective reductions catalyst (SCR) systems, such as low-speed driving conditions, more effective technology options (e.g., dedicated natural gas buses and electric buses) should be considered by policy makers in Macao. We identified strong effects of the vehicle size, engine displacement and driving conditions on real-world CO 2 emission factors and fuel consumption for diesel vehicles. Therefore, detailed profiles regarding vehicle specifications can reduce the uncertainty in their fleet-average on-road fuel consumption. In addition, strong correlations between relative emission factors and driving conditions indicated by the average speed of generated micro-trips are identified based on a micro-trip method. For example, distance-based emission factors of HDBs will increase by 39% for CO, 29% for THC, 43% for NO X and 26% for CO 2 when the average speed decreases from 30 km h −1 to 20 km h −1 . The mitigation of on-road emissions from diesel buses and trucks by improving traffic conditions through effective traffic and economic management measures is therefore required. This study demonstrates the important role of PEMS in understanding vehicle emissions and mitigation strategies from science to policy perspectives. [ABSTRACT FROM AUTHOR]

Weekly inventories for emissions of agricultural ammonia were calculated for 139 4 × 4 km grid cells over 52 weeks in the intensely farmed Lower Fraser Valley, BC. The grid cells were located both inside and outside an area that had been depopulated of poultry due to an outbreak of Avian Influenza prior to the start of the study. During the study period, ambient ammonia concentrations were measured hourly at two locations outside the cull area and one location inside the cull area. Large emission differences between grid cells and differences in temporal variation between cells were related to farming practices and meteorological factors such as temperature and rainfall. Weekly average ambient concentrations at the three sampling locations were significantly correlated with estimates of weekly emissions for many of the grid cells in the study area. Inside the cull area, ambient concentrations during the cull (week 1) were 37% of the concentrations after the cull (week 52), while outside the cull there was almost no difference between week 1 and week 52, suggesting that in normal (non-cull) conditions, about 60% of the ambient ammonia was due to poultry farms. Estimated emissions in weeks 1 and 52 for grid cells affected by the cull indicated that over 90% of the emissions came from poultry. The discrepancy in difference between week 1 and 52 for emissions and ambient concentrations could be due to atmospheric factors like transport, atmospheric reactions, dispersion or deposition; to errors in the inventory including farming data, emission factors; and omission of some non-poultry emission sources. Overall the study supports the ammonia emission inventory estimates. Detailed emission data helps in modeling ammonia in the atmosphere and is useful for developing abatement policy. [ABSTRACT FROM AUTHOR]

Long-term trend of the atmospheric NO 2 was analyzed using ambient monitoring data collected from seven major cities in Korea over two decades (1989–2010). In light of the notable environmental policies initiated since June 2000, these NO 2 data were also evaluated after dividing the entire study period into period I (1989–1999) and period II (2000–2010). Accordingly, the mean concentrations of NO 2 in five out of seven cities in period II were higher by 1–26% than period I. This recognizable increase in period II is likely to reflect the effect of increasing consumption rates in primary energy (e.g., petroleum and LNG). An examination of the seasonal trend of NO 2 consistently indicates the highest concentrations occurred during winter because of the combined effects of the anthropogenic emission and meteorological conditions. A health risk assessment of our data indicated that the NO 2 exposure (to adults, children, and infants) increased from period I to period II. Also, the long-term trends of NO 2 were analyzed based on the seasonal Mann–Kendall test and the Sen's slopes. It revealed that NO 2 levels of most cities had the linearly increasing trends during period I. However, decreasing trends appeared during period II to reflect the direct effect of implementation of administrative efforts including the fuel switching control policy. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3 ) emissions from agriculture to the atmosphere, along with emissions of other pollutants from a variety of sources, are of concern to agriculture worldwide. National emissions from agricultural sources in Canada are linked to domestic consumption and export demand for agricultural products. The onus to limit emissions is often directed to the producers, but the marketplace and consumer are also responsible for the environmental impact of their choices. This objective of this study was to quantitatively link agricultural NH 3 emissions to per person consumption of food and protein and to agricultural exports from Canada. There are substantial differences in the NH 3 emissions per unit consumed protein among the various food types. As a result, shifts in the Canadian diet have had a large impact on relative per person NH 3 emissions. From 1981 to 2006, the total per person protein intake in the Canadian diet increased about 5%, but NH 3 emission related to that diet decreased 20%. This is largely related to consumption of less beef, which has a high emission per unit of meat or protein, and more poultry and cereals which have much lower emissions. Although these changes in diet were not because of environmental concerns by the consumers, they had substantial effects on national-level emissions. These consumer driven effects may well exceed the possible effects of best management practices intended to address NH 3 emissions at the producer level. Note that the Canadian population has increased 50% from 1981 to 2006 and meat and egg exports increased 570%, so that total emissions from food production in Canada have increased. Our results imply there will be further effects on national NH 3 emissions because of dietary and export drivers that are generally outside the scope of agro-environmental policy. [ABSTRACT FROM AUTHOR]

A dynamic evaluation of the Community Multiscale Air Quality (CMAQ) modeling system version 5.0.1 was conducted to evaluate the model's ability to predict changes in ozone levels between 2002 and 2005, a time period characterized by emission reductions associated with the EPA's Nitrogen Oxides State Implementation Plan as well as significant reductions in mobile source emissions. Model results for the summers of 2002 and 2005 were compared to simulations from a previous version of CMAQ to assess the impact of model updates on predicted pollutant response. Changes to the model treatment of emissions, meteorology and chemistry had substantial impacts on the simulated ozone concentrations. While the median bias for high summertime ozone decreased in both years compared to previous simulations, the observed decrease in ozone from 2002 to 2005 in the eastern US continued to be underestimated by the model. Additional “cross” simulations were used to decompose the model predicted change in ozone into the change due to emissions, the change due to meteorology and any remaining change not explained individually by these two components. The decomposition showed that the emission controls led to a decrease in modeled high summertime ozone close to twice as large as the decrease attributable to changes in meteorology alone. Quantifying the impact of retrospective emission controls by removing the impacts of meteorology during the control period can be a valuable approach for communicating to policy makers the net benefit of national control measures. [ABSTRACT FROM AUTHOR]

Abstract: To design and implement an effective emission control strategy for black carbon (BC), the locations and strength of BC sources must be identified. Lack of accurate source information from the Russian Federation has created difficulty for a range of research and policy activities in the Arctic because Russia occupies the largest landmass in the Arctic Circle. A project was initiated to resolve emission sources of BC in the Russian Federation by using the Potential Source Contribution Function (PSCF). It used atmospheric BC data from two Arctic sampling stations at Alert Nunavut, Canada, and Tiksi Bay, Russia. The geographical regions of BC emission sources in Russia were identified and summarized as follows: (1) a region surrounding Moscow, (2) regions in Eurasia stretching along the Ural Mountains from the White Sea to the Black Sea, and (3) a number of scattered areas from western Siberia to the Russian Far East. Particulate potassium ions, non-marine sulfate, and vanadium were used to assist in resolving the source types: forest fire/biomass burning, coal-fired power plant, and oil combustion. Correlating these maps with the BC map helped to resolve source regions of BC emissions and connect them to their corresponding source types. The results imply that a region south of Moscow and another north of the Ural Mountains could be significant BC sources, but none of the grid cells in these regions could be linked to forest fires, oil combustion, or coal-fired power plants based on these three markers. [Copyright &y& Elsevier]

Abstract: China has suffered from serious air pollution and CO2 emission. Challenges of emission reduction policy not only come from technology advancement, but also generate from the fact that, China has pronounced disparity between regions, in geographical and socioeconomic. How to deal with regional disparity is important to achieve the reduction target effectively and efficiently. This research conducts a spatial analysis on the emission patterns of three air pollutants named SO2, NO x and PM2.5, and CO2, in China's 30 provinces, applied with spatial auto-correlation and multi regression modeling. We further analyze the regional disparity and inequity issues with the approach of Lorenz curve and Gini coefficient. Results highlight that: there is evident cluster effect for the regional air pollutants and CO2 emissions. While emission amount increases from western regions to eastern regions, the emission per GDP is in inverse trend. The Lorenz curve shows an even larger unequal distribution of GDP/emissions than GDP/capita in 30 regions. Certain middle and western regions suffers from a higher emission with lower GDP, which reveal the critical issue of emission leakage. Future policy making to address such regional disparity is critical so as to promote the emission control policy under the “equity and efficiency” principle. [Copyright &y& Elsevier]

Abstract: Methane is a potent greenhouse gas, 21 times as powerful as carbon dioxide in contributing to climate change on a ton-for-ton basis. Methane, along with other short-lived forcers such as black carbon and tropospheric ozone, could play an important role in addressing global climate change. This stems both from their overall effect on climate systems, and from their concentrated impact in the short term. Because reducing emissions of such short-lived pollutants may have a large near-term impact in slowing climate change, the United States and other countries have come together to cooperate under the Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants, and other partnerships such as the Global Methane Initiative. For global impact, the success of such partnerships depends on their ability to scale up project-specific emission reductions. This paper assesses options and challenges for scaling based on a case study of Russia's oil and gas sector. We examine the challenges to achieving far-reaching emission reductions, successes of companies to date, how Russia has sought to influence methane emissions through its environmental fine system, and options for helping companies achieve large-scale emission reductions in the future through simpler and clearer incentives. [Copyright &y& Elsevier]

Abstract: As a pioneer in controlling vehicle emissions within China, Beijing released the Clean Air Action Plan 2013–2017 document in August 2013 to improve its urban air quality. It has put forward this plan containing the most stringent emission control policies and strategies to be adopted for on-road vehicles of Beijing. This paper estimates the historic and future trends and uncertainties in vehicle emissions of Beijing from 1998 to 2020 by applying a new emission factor model for the Beijing vehicle fleet (EMBEV). Our updated results show that total emissions of CO, THC, NO x and PM2.5 from the Beijing vehicle fleet are 507 (395–819) kt, 59.1 (41.2–90.5) kt, 74.7 (54.9–103.9) kt and 2.69 (1.91–4.17) kt, respectively, at a 95% confidence level. This represents significant reductions of 58%, 59%, 31% and 62%, respectively, relative to the total vehicle emissions in 1998. The past trends clearly posed a challenge to NOx emission mitigation for the Beijing vehicle fleet, especially in light of those increasing NO x emissions from heavy-duty diesel vehicles (HDDVs) which have partly offset the reduction benefit from light-duty gasoline vehicles (LDGVs). Because of recently announced vehicle emission controls to be adopted in Beijing, including tighter emissions standards, limitations on vehicle growth by more stringent license control, promotion of alternative fuel technologies (e.g., natural gas) and the scrappage of older vehicles, estimated vehicle emissions in Beijing will continue to be mitigated by 74% of CO, 68% of THC, 56% of NO x and 72% of PM2.5 in 2020 compared to 2010 levels. Considering that many of the megacities in China are facing tremendous pressures to mitigate emissions from on-road vehicles, our assessment will provide a timely case study of significance for policy-makers in China. [Copyright &y& Elsevier]

Abstract: A regulation was implemented on 9/1/2009, excluding Euro 0, I and II heavy duty vehicles from entering Amsterdam's Low Emission Zone (LEZA). The current study investigated whether and to what extent this regulation had an effect on air quality. Data for a period starting two years before the regulation up to 31 December 2010 were obtained from two monitoring sites within the LEZA, one located in a street frequently used by heavy-duty vehicles, and one at an urban background location. The difference in concentrations of NO2, NOx, PM10 and soot, between the two sites was attributed to traffic. Soot was measured by two proxies, Elemental Carbon (EC) and Absorbance that showed a significant mutual correlation. The traffic contribution concentrations measured were adjusted for wind direction, wind speed, type of day (weekday/weekend) and traffic intensity. Since the implementation of the LEZA, the traffic contribution concentrations compared to the roadside site concentrations were decreased by 4.9% (95%-CI: 3.0–6.9%) for NO2, 5.9% (95%-CI: 3.7–6.4%) for NOx, 5.8% (95%-CI: 3.3–8.4%) for PM10, 7.7% (95%-CI: 2.3–13.0%) for Absorbance and 12.9% (95%-CI: 5.2–20.5%) for EC. The current study demonstrated significant decreases in traffic-related air pollution concentrations in the vicinity of a roadside monitoring station after the implementation of a low emission zone in Amsterdam. [Copyright &y& Elsevier]

Abstract: The uncertain, future development of emissions of short-lived trace gases and aerosols forms a key factor for future air quality and climate forcing. The Representative Concentration Pathways (RCPs) only explore part of this range as they all assume that worldwide ambitious air pollution control policies will be implemented. In this study, we explore how different assumptions on future air pollution policy and climate policy lead to different concentrations of air pollutants for a set of RCP-like scenarios developed using the IMAGE model. These scenarios combine low and high air pollution variants of the scenarios with radiative forcing targets in 2100 of 2.6 W m−2 and 6.0 W m−2. Simulations using the global atmospheric chemistry and transport model TM5 for the present-day climate show that both climate mitigation and air pollution control policies have large-scale effects on pollutant concentrations, often of similar magnitude. If no further air pollution policies would be implemented, pollution levels could be considerably higher than in the RCPs, especially in Asia. Air pollution control measures could significantly reduce the warming by tropospheric ozone and black carbon and the cooling by sulphate by 2020, and in the longer term contribute to enhanced warming by methane. These effects tend to cancel each other on a global scale. According to our estimates the effect of the worldwide implementation of air pollution control measures on the total global mean direct radiative forcing in 2050 is +0.09 W m−2 in the 6.0 W m−2 scenario and −0.16 W m−2 in the 2.6 W m−2 scenario. [Copyright &y& Elsevier]

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

Abstract: In this study, the emission inventories of NO x , which is a major air pollutant of South Korea were compared and analyzed. The two bottom-up emission inventories, Clean Air Policy Support System (CAPSS) and Regional Emission inventory in ASia (REAS), which are the latest emission inventories about the air pollutant emissions about South Korea were compared to find out the trend of NO x emission during 1996–2005. Also, these two emission inventories were compared with the top down NO x emissions estimated from satellite observations to validate the amount of NO x emitted from South Korea. The total NO x emission trends, sectoral and regional comparisons were carried out. The trend of the top down estimated NO x emission was similar to CAPSS and REAS. However, the magnitudes of the top down estimated NO x emission were usually closer to those of CAPSS than those of REAS. The NO x emissions from transportation sector of REAS were larger than that of CAPSS, and this corresponded to the difference of total amount of NO x emission between CAPSS and REAS. By comparing the differences of the ratios of the vehicle kilometers traveled (VKT) and emission factors (EFs), it was identified that most of the difference between CAPSS and REAS was due to these factors for diesel vehicles in REAS. Implications of this higher VKT values in REAS were discussed. [Copyright &y& Elsevier]

Abstract: China's air pollution control policies during the 12th Five Year Plan (2011–2015) are characterized by the targets of 10% nitrogen oxides (NO x ) reduction and 8% sulfur dioxide (SO2) reduction from the 2010 levels. In this study, the Community Multi-scale Air Quality (CMAQ) modeling system was used to evaluate the impact of only SO2, only NO x , and joint SO2/NO x control measures on particulate matter pollution, the greatest concern for urban air quality in China. Four emission scenarios were developed for 2015, including a business-as-usual scenario, a reference NO x control scenario based on the governmental plan, an accelerated NO x control technology scenario, and a scenario assuming joint controls of NO x and SO2 based on the governmental plan. Under the planned NO x control measures, the annual mean concentrations of particulate matter less than or equal to 2.5 μm (PM2.5) decline by 1.5–6 μg m−3, i.e. 1.6%–8.5%, in the majority of eastern China. The largest reduction occurs in the middle reach of the Yangtze River. Under accelerated NO x control measures, the annual average PM2.5 concentration reductions (compared with the business-as-usual scenario) in eastern China are 65% higher than the reductions under planned control measures. The unusual increase of PM2.5 concentrations in the North China Plain and the Yangtze River Delta during January after the reductions of NO x emissions was an integrated effect of excessive NO x , the ammonia-rich inorganic aerosol chemistry, and the non-methane volatile organic compounds (NMVOC) sensitive photochemical regime. Under the joint controls of NO x and SO2, the annual mean PM2.5 concentrations decline over 3 μg m−3, i.e. 3.2%–13%, in the majority of eastern China, and some areas in the middle reach of the Yangtze River have reductions as large as 6–8.3 μg m−3, i.e. 5.0%–13%. The average PM2.5 concentration reductions in eastern China are 1.20 μg m−3, 3.14 μg m−3, 3.57 μg m−3, 4.22 μg m−3 in January, May, August, and November, respectively. The corresponding declining rates are 2.3%, 12.2%, 14.3%, and 8.1%, respectively. More stringent policies should be implemented in winter to reduce the heavy pollution periods. The annual average PM2.5 concentration reductions in three major city clusters are comparable with the average reductions of eastern China. Stringent regional control policies are required for the significant improvement of particulate air quality in major city clusters. [Copyright &y& Elsevier]

Abstract: The air quality impacts of aviation are becoming increasingly important given their impact on human health and the projected growth of aviation. In the United States, the government has set targets to manage and reduce the environmental impacts of aviation. In an environmental policy assessment context it is often necessary to rapidly evaluate many possible scenarios, and quantification of uncertainty is important. This makes direct application of comprehensive air quality models such as the Community Multiscale Air Quality (CMAQ) modeling system impractical due to computational cost. Here we develop a response surface model (RSM) – a form of rapid surrogate model – of the impact of aviation emissions on air quality in the United States. We develop an RSM design space and populate it with results from 46 CMAQ simulations, and perform cross-validation of the resultant RSM. The RSM models present-day as well as future impacts amid changing population and non-aviation emissions sources. This enables rapid estimates of the (particulate matter) air quality and human health impacts of aviation emissions scenarios. Cross-couplings between precursor gaseous emissions and PM2.5 species are found, consistent with competition for atmospheric ammonia. We apply the RSM to quantify the human health benefits of emissions reductions in 2018. Using the RSM we estimate that in 2005, aviation landing and takeoff emissions cause ∼195 [90% CI: 80–340] early deaths, while the same emissions cause ∼350 [90% CI: 145–610] mortalities in 2018. An emissions tradespace between aviation NO x and SO x emissions is constructed. It is found that with fleet-wide desulfurization of jet fuel, a 35% reduction in aviation NO x emissions would result in maintaining the same level of aviation-attributable early deaths in 2018 relative to 2005 levels, while an 80% reduction in NO x emissions would half aviation-attributable early deaths. [Copyright &y& Elsevier]

Abstract: Traffic related air pollution is a major health concern in many countries. The potential costs and benefits of different abatement policies are usually estimated by either models, case studies or previously implemented intervention measures. Such estimations have, however, limited ability to predict the effect of a reduction in primary pollutants' emissions on secondary pollutants such as ozone, because of the nonlinear nature of the photochemical reactions. This study examines the short term effects of a drastic change in emissions on a national scale during the Jewish holiday of Day of Atonement (DA) in Israel. During the holiday nearly all anthropogenic emission sources are ceased for a period of 25 h, including all vehicles, commercial, industrial and recreational activities. DAs during the 15 years period of 1998–2012 are analyzed at three sites with respect to primary and secondary air pollutants, and in greater details for 2001. A dramatic decrease in primary pollutants emissions (83–98% in NO) causes an 8 ppbv increase in ozone at the urban core. Downwind (27 km), ozone decreases by only 5 ppbv. Nighttime O3 is shown to increase to 20 ppbv at the urban sites and 30 ppbv downwind. In spite of the striking reduction in emissions, changes in ozone are not greater than what is reported in the literature about less significant events like the ozone weekend effect. Changes in ambient pollution levels observed during DA provide some indication to the possible outcomes of a major change in anthropogenic emissions. These may be considered as the best case scenario for emissions reduction intervention measures and thus aid policy makers in evaluating potential benefits of such measures. [Copyright &y& Elsevier]

Abstract: Emissions from burning major agricultural residue were measured through laboratory simulations using a self-designed dilution chamber system. Emission factors of CO2, CO, non-methane hydrocarbons (NMHCs), oxygenated volatile organic compounds (OVOCs), PM10, PM2.5, OC and EC in PM2.5 were measured for burning rice straw in flaming and smoldering combustion, and for burning of sugarcane leaves. NMHCs emitted from crop straw open burning were dominated by C2 hydrocarbons (ethene, ethane, ethyne), contributing (53.4 ± 4.6)% in volume in rice straw burning emissions and 41.8% in sugarcane burning emissions, respectively. Acetone and aldehyde were major OVOCs species in open straw burning emissions. A survey was conducted to determine the fraction of field crop biomass burned during harvesting season and the amounts of household firewood and crop residue consumption in 2008. Information obtained from the survey, together with measured EFs for field burning of rice straw and sugarcane, and EFs from literatures for field burning of other agricultural residues, biofuel combustion and forest fires, were used in developing the source inventories of carbonaceous pollutants in the PRD region. The annual emissions of CO, VOCs (including NMHCs and OVOCs), NO x , PM2.5, OC and EC from burning biomass were estimated to be 186.38, 15.94, 4.93, 15.56, 7.10, 2.25 kt in the year 2008, respectively. These estimates are lower than previously published estimates by 23–63%. Open burning patterns (flaming and smoldering) and rural biofuel use contribute to the differences. Field burning of straw contributed mainly to VOCs, PM2.5 and OC emissions while the residential sector was the dominant source of EC, CO and NO x . The contributions of biomass burning to entire PRD emissions are estimated as 3.37–6.53%, respectively, for PM, and 1.82–3.17%, respectively, for VOCs, and 0.52–2.77%, respectively, for NO x . [Copyright &y& Elsevier]

Particle number size distributions were simultaneously measured at the Guangzhou (GZ) urban site (23.13°N, 113.26°E) and the Back-garden (BG) rural site (23.5°N, 113.03°E) in the Pearl River Delta (PRD) region in July, 2006. It provided new findings into the evolution of particle number size distribution and new particle formation (NPF) in two different environments. Number concentration of particles (20 nm–10 μm diameter) at GZ was about 70% higher than at BG and significantly affected by traffic emission. However, number concentrations of the regional aerosols (100–660 nm) were (6 ± 3) × 103 cm−3 at both sites. At BG, the diurnal variation of particle number size distributions showed an obvious particle growth process beginning at about 9:00 (LT), probably caused by NPF. In contrast, particle number concentrations in the size rages of 20–45 nm, 45–100 nm, and 100–660 nm showed similar trends with two main peaks at about 12:00 (LT) and 19:00 (LT) at GZ. NPF events were observed at both sites, but the occurrence frequency at GZ was about 50% lower than at BG. Regional NPF events at both sites probably in the same air mass were simultaneously observed with similar growth rates, concentrations and production rates of the condensable vapors, and condensational sinks on July 6. On the whole, deceasing traffic emission will improve air quality efficiently in the aspect of particle number concentration and fine particulate pollution in the summer of PRD should be controlled in a regional scale, especially with stagnant air mass from South China Sea. [ABSTRACT FROM AUTHOR]

Abstract: In recent years, Mainland China, and in particular the industrial hotbed of the Pearl River Delta (PRD) has experienced an increasingly serious problem of high concentrations of airborne particulate matter. Following the tightening-up of China's air quality policies in recent years, and with especially fine particles now added to a new air quality objective, the identification of major source regions and major types of pollutants has become crucial. In this study, the Comprehensive Air Quality Model (CAMx), together with the Particulate Source Apportionment Technology (PSAT) source apportionment method, has been applied to analyze how different emission activities influence PM concentration in the PRD region. By using this method, a detailed source region and emission category contribution matrix is derived for all regions within the Hong Kong/PRD region and source appointment results show that, on average, for different cities super-regional transport and mobile vehicles are the two major fine particle sources, contributing 62% (34.3 μg m−3) and 21% (12.2 μg m−3) of the total figure in December, and 42% (13.1 μg m−3) and 28% (9.7 μg m−3) in April. Meanwhile, over the same period in Hong Kong, in addition to these two factors, marine proved another very significant source of particle pollutant, amounting to 18% of the total figure (4.7 μg m−3). Another important cause of high PM levels has been the transport of fine particles between cities within the PRD region, with three different regions selected for detailed analysis. Results show that for the Hong Kong/PRD region local reduction of mobile sources and collaboration between different areas could have succeeded in alleviating the air pollution problem. [Copyright &y& Elsevier]

Abstract: Ground-level ozone is a secondary pollutant that causes serious health and environmental damage. One of the main challenges in controlling ground-level ozone is to identify the categories of ozone precursor species that contribute the most to ozone levels, and the regions from which they are emitted. In this study, we apply a photochemical model source apportionment tool to identify the contributions of various precursors to seasonal ozone levels in Hong Kong (HK) and the Pearl River Delta (PRD) region, according to their source regions and categories. We establish a full precursor contribution matrix for the ozone concentrations in all cities within the HK/PRD region. This matrix can be used to rank the relative importance of precursors by source region/category for each city. It can also be used to show how the precursor emissions from any city/category affect ozone levels in neighboring cities. The results show substantial seasonal variation in the source contributions from the HK/PRD region. During ozone episodes, precursors from the region accounted for 68–80% of ozone concentrations in July and 35–55% in October, but only 19–32% in January and April. For all of the cities in the PRD, the top three precursor categories contributing to ozone episodes were mobile, point and area sources. Biogenic and point sources were more important in July than in October. In contrast, the ranking of contributing source regions showed considerable variation across cities and seasons, implying substantial variations in the ways in which precursors from one city affect ozone levels in neighboring cities. Our results show that source contribution and impact analysis can be very useful for evaluating the ozone control strategies of local governments. For the PRD region, a local reduction in mobile, area and point sources, together with regional collaborations on pollution control, are of particular importance in effectively reducing episodic ozone concentrations. [Copyright &y& Elsevier]

Abstract: A new exhaust emission inventory of ocean-going vessels (OGVs) was compiled for Hong Kong by using Automatic Identification System (AIS) data for the first time to determine typical main engine load factors, through vessel speed and operation mode characterization. It was found that in 2007, container vessel was the top emitting vessel type, contributing 9,886, 11,480, 1,173, 521 and 1166 tonnes of SO2, NO x , PM10, VOC and CO, respectively, or about 80%–82% of the emissions. The top five, which also included ocean cruise, oil tanker, conventional cargo vessel and dry bulk carrier, accounted for about 98% of emissions. Emission maps, which add a new spatial dimension to the inventory, show the key emission hot spots in Hong Kong and suggest that a significant portion of emissions were emitted at berth. Scientific evidence about the scale and distribution of ship emissions has contributed in raising public awareness and facilitating stakeholder engagement about the issue. Fair Winds Charter, the world's first industry-led voluntary emissions reduction initiative, is a perfect example of how careful scientific research can be used in public engagement and policy deliberation to help drive voluntary industry actions and then government proposals to control and regulate marine emissions in Hong Kong and the Pearl River Delta region. [Copyright &y& Elsevier]

Abstract: With the new air quality standards forthcoming in China, the Pearl River Delta region is facing new challenges to achieve its air quality goal. The success of the emission reduction measures introduced by local authorities in the run-up to the Guangzhou Asian Games demonstrated that the Pearl River Delta air quality can be improved by introducing integrated emission reduction measures. This paper combines observation data, emission reduction measures, and air quality simulations that were applied during the Asian Games (12–27 November 2010) to analyze the relationship between emissions and concentrations of pollutants in Guangzhou. The Asian Games abatement strategy totally reduced emissions of 41.1% SO2, 41.9% NO x , 26.5% PM10, 25.8% PM2.5 and 39.7% VOC. The concentrations of SO2, NO2, PM10 and PM2.5 were reduced by 66.8%, 51.3%, 21.5% and 17.1%, respectively. In Guangzhou, the main challenge to be overcome with the new air quality daily requirements is mostly for NO2, PM2.5, and hourly ozone maxima. If pollutants maintain the same concentrations before and after the Asian Games, there will be 47.4% and 31.6% non-attainment days for NO2 and PM2.5 respectively as a period average. Although PM10 concentration can meet the daily limits (150 μg m−3), it is quite difficult to meet the annual limit value (70 μg m−3). One important implication is that the long-term, step-by-step integrated measures of the past six years work better than the strict, intensive, short-term measures on SO2, NO2 and VOC control. Dust control by limiting construction sites and watering the roads can further reduce 12.8% of the PM10 concentration. However, to reduce ambient PM2.5, the abatement strategy should be more complex and extensive. On the contrary, ozone pollution was not improved during the Asian Games, indicating that alleviation strategies should be improved by scientific studies to determine the appropriate control ratio of NO2 and VOC in the Pearl River Delta region. [Copyright &y& Elsevier]

Abstract: Ambient air measurements of volatile organic compounds (VOCs) and oxygenated volatile organic compounds (OVOCs) were conducted and characterised during a two-year grid study in the Pearl River Delta (PRD) region of southern China. The present grid study pioneered the systematic investigation of the nature and characteristics of complex VOC and OVOC sources at a regional scale. The largest contributing VOCs, accounting over 80% of the total VOCs mixing ratio, were toluene, ethane, ethyne, propane, ethene, butane, benzene, pentane, ethylbenzene, and xylenes. Sub-regional VOC spatial characteristics were identified, namely: i) relatively fresh pollutants, consistent with elevated vehicular and industrial activities, around the PRD estuary; and ii) a concentration gradient with higher mixing ratios of VOCs in the west as compared with the eastern part of PRD. Based on alkyl nitrate aging determination, a high hydroxyl radical (OH) concentration favoured fast hydrocarbon reactions and formation of locally produced ozone. The photochemical reactivity analysis showed aromatic hydrocarbons and alkenes together consisted of around 80% of the ozone formation potential (OFP) among the key VOCs. We also found that the OFP from OVOCs should not be neglected since their OFP contribution was more than one-third of that from VOCs alone. These findings support the choice of current air pollution control policy which focuses on vehicular sources but warrants further controls. Industrial emissions and VOCs emitted by solvents should be the next targets for ground-level ozone abatement. [Copyright &y& Elsevier]

Abstract: Total emission control of sulfur has been stringently implemented in the last two five-year plans (2000–2010), as a key national environmental policy in China. As a result of this policy, SO2 emissions in the Pearl River Delta (PRD) region were reduced by 212.5 kilotons. The regional monitoring network data indicate a 39% reduction of ambient SO2 concentrations between 2006 and 2009. SCIAMACHY satellite data show a 27% decrease in the whole column SO2 concentration during the same period. To assess what role changes in meteorology contributed to the observed changes in concentrations in this time period, sensitive experiments for November of 2006 and 2009 where different combinations of changing emissions under constant meteorology and vice versa were simulated using the MM5-STEM model. In general, the model can well capture the day-to-day variation patterns of meteorology and ambient SO2. At the regional scale, long-term emission controls constantly reduce ambient SO2 and sulfate concentrations, while meteorology has negative and positive effects in the PRD. The contribution of meteorological effects to the composite difference of SO2 concentration varied in different cities, ranging from −20% to 33%. According to meteorological effects, three categories of cities were established and indicated the meteorological role in different cities. Regional transport is very important to WQS site, ranging from −39 to +67 μg m−3 for the SO2 concentration. Both the meteorological conditions and trans-boundary transport play important and complex role in the linkage between emission and ambient concentration. [Copyright &y& Elsevier]

Abstract: The information provided by the scientific studies and control measures implemented in the Pearl River Delta (PRD) region of China reveals that tremendous progress has been made in the understanding of regional air pollution issues and the deployment of mitigation measures for alleviating these problems. Given the unparalleled rapid economic growth in the PRD over the past two decades, such progress was only made possible by strong, science-based support and the partnerships between government and research institutions in the region and overseas. Researchers from these partnership programs and related studies have deployed cutting-edge expertise and experience in various crucial mainland China and mainland China/Hong Kong-level projects. China recognizes the importance of protecting the environment and cleaning up the air in the pursuit of sustainable growth and economic development. To avoid falling into a cycle of event-driven clean-up efforts, China has recently taken a major step and updated the national ambient air quality standards. Clearly, China is implementing an increasing number of evidence-based policies to address air pollution problems. Thus, to bring a fresh impetus at a national level, the PRD must maintain and augment the Hong Kong-mainland collaborative momentum, inducing a “whole-China” effort to clean up air pollution. To strengthen the science-based support system and ensure continuous and concerted effort in implementing the regional multi-pollutant control strategy, there must be an overarching and integral Hong Kong–Guangdong science consortium framework supporting the formulation of regional policy and control measures built on common goals under the “one country, two systems” principle. The “PRD Approach” of the air quality management regime reflected regional cooperative efforts in synchronous air pollutant control, catalyzed the crucial role of information disclosure and subtly transformed the air quality management approach to overcome the nation's new air pollution challenges. [Copyright &y& Elsevier]

Abstract: The Guangzhou government adopted many vehicle emission control policies and strategies during the five-year preparation (2005–2009) to host the 2010 Asian Games. This study established a multi-year emission inventory for vehicles in Guangzhou during 2005–2009 and estimated the uncertainty in total vehicle emissions by taking the assumed uncertainties in fleet-average emission factors and annual mileage into account. In 2009, the estimated total vehicle emissions in Guangzhou were 313 000 (242 000–387 000) tons of CO, 60 900 (54 000–70 200) tons of THC, 65 600 (56 800–74 100) tons of NO x and 2740 (2100–3400) tons of PM10. Vehicle emissions within the urban area of Guangzhou were estimated to be responsible for ∼40% of total gaseous pollutants and ∼25% of total PM10 in the entire city. Although vehicle use intensity increased rapidly in Guangzhou during 2005–2009, vehicle emissions were estimated to have been reduced by 12% for CO, 21% for THC and 20% for PM10 relative to those in 2005. NO x emissions were estimated to have remained almost constant during this period. Compared to the “without control” scenario, 19% (15%–23%) of CO, 20% (18%–23%) of THC, 9% (8%–10%) of NO x and 16% (12%–20%) of PM10 were estimated to have been mitigated from a combination of the implementation of Euro III standards for light-duty vehicles (LDVs) and heavy-duty diesel vehicles and improvement of fuel quality. This study also evaluated several enhanced vehicle emission control actions taken recently. For example, the enhanced I/M program for LDVs was estimated to reduce 11% (9%–14%) of CO, 9% (8%–10%) of THC and 2% (2%–3%) of NO x relative to total vehicle emissions in 2009. Total emission reductions by temporary traffic controls for the Asian Games were estimated equivalent to 9% (7%–11%) of CO, 9% (8%–10%) of THC, 5% (5%–6%) of NO x and 10% (8%–13%) of PM10 estimated total vehicle emissions in 2009. Those controls are essential to further vehicle emission mitigation in Guangzhou required by the new National Ambient Air Quality Standards. [Copyright &y& Elsevier]

Abstract: In recent years, heavy metal pollution accidents were reported frequently in China. The atmospheric heavy metal pollution is drawing all aspects of attention. This paper summarizes the recent research results from our studies and previous studies in recent years in China. The level, temporal variation, seasonal variation and size distribution of the heavy metals of atmospheric Lead(Pb), Vanadium(V), Manganese(Mn), Nickel(Ni), Chromium(Cr), Cadmium(Cd), Copper(Cu), Zinc(Zn) and Arsenic(As) were characterized in China. The emission characteristics and sources of atmospheric heavy metals and As in China were reviewed. Coal burning, iron and steel industry and vehicle emission are important sources in China. Control policies and effects in China were reviewed including emission standards, ambient air quality standards, phase out of leaded gasoline and so on, and further works for atmospheric heavy metals control were suggested. The comprehensive heavy metals pollution control measures and suggestions were put forward based on the summarization of the development and experience of the atmospheric heavy metal pollution control abroad. [Copyright &y& Elsevier]

Abstract: For policy-making, human health risks of fine particulate m(PM2.5) are commonly assessed by comparing environmental concentrations with reference values, which does not necessarily reflect the impact on health in a population. The goal of this study was to compare health impacts in the Moerdijk area, The Netherlands resulting from local emissions of PM2.5 from industry and traffic in a case study using the risk advancement period (RAP) of mortality. The application of the RAP methodology on the local scale is a promising technique to quantify potential health impacts for communication purposes. The risk advancement period of mortality is the time period by which the mortality risk is advanced among exposed individuals conditional on survival at a baseline age. The RAP showed that road traffic was the most important local emission source that affects human health in the study area, whereas the estimated health impact from industry was a factor of 3 lower. PM2.5 due to highway-traffic was the largest contributor to the health impact of road traffic. This finding is in contrast with the risk perception in this area. [Copyright &y& Elsevier]

Abstract: Monte Carlo sampling of pre-specified parameter ranges has been used to replace single ‘best estimate’ Photochemical Trajectory Model runs with 9006 ‘acceptable’ model runs that were each consistent with the observations of elevated O3 during July 2006 at a rural location in southern England. These acceptable parameter sets were then used for probabilistic evaluation of policy relevant photochemical oxidant control strategies, based on 30% reductions in VOC and NO x precursor emissions and the geographic locations where the emission reductions were carried out. Indicator species ratios were used to complete a diagnostic evaluation of model performance. The chemical mechanism employed in the base case model was replaced with four other mechanisms from the literature. Probabilistic uncertainty analysis showed that the results of the policy-relevant scenarios showed little or no sensitivity to chemical mechanism choice. A large degree of error compensation could be achieved through the selection of acceptable parameter sets and this hid the differences between the five chemical mechanisms studied. [Copyright &y& Elsevier]

Abstract: The potential adverse human health impacts of emissions from UK airports have become a significant issue of public concern. We produce an inventory of UK airport emissions – including emissions from aircraft landing and takeoff operations, aircraft auxiliary power units (APUs) and ground support equipment (GSE) – with quantified uncertainty. Emissions due to more than 95% of UK passenger enplanements are accounted for. We apply a multi-scale air quality modelling approach to assess the air quality impacts of UK airports. Using a concentration-response function we estimate that 110 (90% CI: 72–160) early deaths occur in the UK each year (based on 2005 data) due to UK airport emissions. We estimate that up to 65% of the health impacts of UK airports could be mitigated by desulphurising jet fuel, electrifying GSE, avoiding use of APUs and use of single engine taxiing. Two plans for the expansion of UK airport capacity are examined – expansion of London Heathrow and new hub airport in the Thames Estuary. Even if capacity is constrained, we find that the health impacts of UK airports still increases by 170% in 2030 due to an increasing and aging population, increasing emissions, and a changing atmosphere. We estimate that if Heathrow were to be expanded as per previous UK Government plans, UK-wide health impacts in 2030 would increase by 4% relative to the 2030 constrained case, but this increase could become a 48% reduction if emissions mitigation measures were employed. We calculate that 24% of UK-wide aviation-attributable early deaths could be avoided in 2030 if Heathrow were replaced by a new airport in Thames Estuary because the location is downwind of London, where this reduction occurs notwithstanding the increase in aircraft emissions. A Thames hub airport would (isolated from knock-on effects at other airports) cause 60–70% fewer early deaths than an expanded Heathrow, or 55–63% fewer early deaths than an unexpanded Heathrow. Finally, replacing Heathrow by a Thames Estuary airport combined with emissions mitigation measures would reduce UK-wide aviation-attributable early deaths by 56% in 2030 while increasing aircraft movements, which would represent aviation causing about the same level of adverse health impacts as today in absolute terms. We note that because aviation emissions are included in the EU Emissions Trading Scheme, all options are CO2-neutral in terms of direct emissions (but not climate-neutral). [Copyright &y& Elsevier]

Abstract: Halocarbon emissions from China are of great interest to both policy makers and academia. To estimate halocarbon emissions with interspecies correlation methods, previous studies adopted CO, HCFC-22 or other species as reference tracers. However, few of these studies compared the results using different reference tracers. In this study, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs) and carbon monoxide (CO) concentrations were measured at a monitoring site in northern China in 2009/2010, and halocarbon emissions were estimated using an interspecies correlation method. A comparison was performed of the correlations between estimated halocarbon emissions and two reference tracers, CO and HCFC-22. The results show that both species are significantly correlated with most of the target species (P < 0.01), whereas HCFC-22 shows better correlations than does CO. Our estimated halocarbon emissions for 2009 agree within uncertainties with results obtained with other approaches, including inverse modeling and interspecies correlation methods. The emissions for 2001–2009 estimated in different studies (all using top–down approaches) show a clear decrease in the emissions of CFC-11 and CFC-12 and an increase in the emissions of HCFC-22, HCFC-141b and HCFC-142b in China. Moreover, the combined Ozone Depletion Potential weighted emissions of CFCs are much greater than the reported consumption, whereas the emissions of HCFC counterparts are not more than one-half of the reported consumption. This result suggests that HCFCs are being accumulated in banks and that these banks will sustain elevated in China. [Copyright &y& Elsevier]