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Millions of people die every year from diseases caused by exposure to outdoor air pollution. Some studies have estimated premature mortality related to local sources of air pollution, but local air quality can also be affected by atmospheric transport of pollution from distant sources. International trade is contributing to the globalization of emission and pollution as a result of the production of goods (and their associated emissions) in one region for consumption in another region. The effects of international trade on air pollutant emissions, air quality and health have been investigated regionally, but a combined, global assessment of the health impacts related to international trade and the transport of atmospheric air pollution is lacking. Here we combine four global models to estimate premature mortality caused by fine particulate matter (PM 2.5 ) pollution as a result of atmospheric transport and the production and consumption of goods and services in different world regions. We find that, of the 3.45 million premature deaths related to PM 2.5 pollution in 2007 worldwide, about 12 per cent (411,100 deaths) were related to air pollutants emitted in a region of the world other than that in which the death occurred, and about 22 per cent (762,400 deaths) were associated with goods and services produced in one region for consumption in another. For example, PM 2.5 pollution produced in China in 2007 is linked to more than 64,800 premature deaths in regions other than China, including more than 3,100 premature deaths in western Europe and the USA; on the other hand, consumption in western Europe and the USA is linked to more than 108,600 premature deaths in China. Our results reveal that the transboundary health impacts of PM 2.5 pollution associated with international trade are greater than those associated with long-distance atmospheric pollutant transport.

Epidemiologic and health impact studies are inhibited by the paucity of global, long-term measurements of the chemical composition of fine particulate matter. We inferred PM2.5 chemical composition at 0.1° × 0.1° spatial resolution for 2004-2008 by combining aerosol optical depth retrieved from the MODIS and MISR satellite instruments, with coincident profile and composition information from the GEOS-Chem global chemical transport model. Evaluation of the satellite-model PM2.5 composition data set with North American in situ measurements indicated significant spatial agreement for secondary inorganic aerosol, particulate organic mass, black carbon, mineral dust, and sea salt. We found that global population-weighted PM2.5 concentrations were dominated by particulate organic mass (11.9 ± 7.3 μg/m(3)), secondary inorganic aerosol (11.1 ± 5.0 μg/m(3)), and mineral dust (11.1 ± 7.9 μg/m(3)). Secondary inorganic PM2.5 concentrations exceeded 30 μg/m(3) over East China. Sensitivity simulations suggested that population-weighted ambient PM2.5 from biofuel burning (11 μg/m(3)) could be almost as large as from fossil fuel combustion sources (17 μg/m(3)). These estimates offer information about global population exposure to the chemical components and sources of PM2.5.

This paper examines Beijing air quality in the winter and summer of 2001 using an integrated air quality modeling system (Fifth Generation Mesoscale Meteorological Model [MM5]/Community Multiscale Air Quality [CMAQ]) in nested mode. The National Aeronautics and Space Administration (NASA) Transport and Chemical Evolution over the Pacific (TRACE-P) emission inventory is used in the 36- (East Asia), 12- (East China), and 4-km (greater Beijing area) domains. Furthermore, we develop a local Beijing emission inventory that is used in the 4-km domain. We also construct a corroborated mapping of chemical species between the TRACE-P inventory and the Carbon Bond IV (CB-IV) chemical mechanism before the integrated modeling system is applied to study ozone (O3) and particulate matter (PM) in Beijing. Meteorological data for the integrated modeling runs are extracted from MM5. Model results show O3 hourly concentrations in the range of 80-159 parts per billion (ppb) during summer in the urban areas and up to 189 ppb downwind of the city. High fine PM (PM2.5) concentrations (monthly average of 75 microg x m(-3) in summer and 150 microg x m(-3) in winter) are simulated over the metropolitan and down-wind areas with significant secondary constituents. A comparison against available O3 and PM measurement data in Beijing is described. We recommend refinements to the developed local Beijing emission inventory to improve the simulation of Beijing's air quality. The 4-km modeling configuration is also recommended for the development of air pollution control strategies.

In the last 10 yr, Beijing has made a great effort to improve its air quality. However, it is still suffering from regional coarse particulate matter (PM10) pollution that could be a challenge to the promise of clean air during the 2008 Olympics. To provide scientific guidance on regional air pollution control, the Mesoscale Modeling System Generation 5 (MM5) and the Models-3/Community Multiscale Air Quality Model (CMAQ) air quality modeling system was used to investigate the contributions of emission sources outside the Beijing area to pollution levels in Beijing. The contributions to the PM10 concentrations in Beijing were assessed for the following sources: power plants, industry, domestic sources, transportation, agriculture, and biomass open burning. In January, it is estimated that on average 22% of the PM10 concentrations can be attributed to outside sources, of which domestic and industrial sources contributed 37 and 31%, respectively. In August, as much as 40% of the PM10 concentrations came from regional sources, of which approximately 41% came from industry and 31% from power plants. However, the synchronous analysis of the hourly concentrations, regional contributions, and wind vectors indicates that in the heaviest pollution periods the local emission sources play a more important role. The implications are that long-term control strategies should be based on regional-scale collaborations, and that emission abatement of local sources may be more effective in lowering the PM10 concentration levels on the heavy pollution days. Better air quality can be attained during the Olympics by placing effective emission controls on the local sources in Beijing and by controlling emissions from industry and power plants in the surrounding regions.

Based on the TRACE-P emission data and a Shanghai local emission inventory, the regional air quality model Models-3/CMAQ was applied with the mesoscale model MM5 to simulate the distribution and transport status of O3 and PM10 in the Yangtze River Delta (YRD) in January and July 2001. Ten days' hourly monitoring data at Shanghai monitoring sites were used to verify the model performance. Results show that the correlation coefficients between monitoring and simulation data of O3 and PM10 are 0.77 and 0.52, and the indices of agreement reach 0.81 and 0.99, respectively. The Models-3 simulation shows a 27% underestimation of the maximum O3 hourly concentration, but performs well in average O3 hourly concentration simulation with a normalized bias of -3.1%. The model shows a 10% underestimation of the average PM10 hourly concentration, with a normalized bias of 46%. Models-3/CMAQ has the ability to simulate the processes of air pollution transport in the YRD, and the model results are acceptable. Among the 16 major cities of the YRD, the maximum O3 hourly concentrations in 14 cities exceed the class II Chinese National Ambient Air Quality Standard (CNAAQS). The high O3 concentration area covers most of the south Jiangsu and north Zhejiang Province. Influenced by local emissions and northerly air pollution transport, the daily average concentrations in Taizhou, Yangzhou, Nanjing, Zhenjiang and Changzhou cities during January of 2001 exceed the Class II national standard. Air pollution transport and chemical transformation are quite obvious in the YRD. In summer, under strong radiation conditions, the air pollutants emitted from southern cities usually impose a negative impact on the downwind cities, due to secondary pollution formation; while under weak radiation conditions, the pollutants impact the surrounding area with primary pollution. In winter, the particle pollution level in the YRD is relatively high, which is closely related to the transportation of particulates from the north area to the YRD. The air pollution in the YRD has developed as a regional problem, rather than just a local one.

An intensive field study was conducted in Sumatra, Indonesia, during a peat fire episode to investigate the physical and chemical characteristics of particulate emissions in peat smoke and to provide necessary data for source-receptor analyses. Ambient air sampling was carried out at three different sites located at varying distances from the peatfires to determine changes in mass and number concentrations of PM2.5 and its chemical composition (carbonaceous and nitrogenous materials, polycyclic aromatic hydrocarbons, water-soluble inorganic and organic ions, and total and water-soluble metals). The three sites represent a rural site directly affected by the local peat combustion, a semirural site, and an urban site situated downwind of the peat fires. The mass concentration of PM2.5 and the number concentration of airborne particles were as high as 1600 microg/m3 and 1.7 x 10(5) cm(-3), respectively, in the vicinity of peat fires. The major components of PM2.5 in peat smoke haze were carbonaceous particles, particularly organic carbon, NO3-, and SO4(2-), while the less abundant constituents included ions such as NH4+, NO2-, Na+, K+, organic acids, and metals such as Al, Fe, and Ti. Source apportionment by chemical mass balance receptor modeling indicates that peat smoke can travel long distances and significantly affect the air quality at locations downwind.

The Chinese "coal-to-gas" and "coal-to-electricity" strategies aim at reducing dispersed coal consumption and related air pollution by promoting the use of clean and low-carbon fuels in northern China. Here, we show that on top of meteorological influences, the effective emission mitigation measures achieved an average decrease of fine particulate matter (PM2.5) concentrations of ∼14% in Beijing and surrounding areas (the "2+26" pilot cities) in winter 2017 compared to the same period of 2016, where the dispersed coal control measures contributed ∼60% of the total PM2.5 reductions. However, the localized air quality improvement was accompanied by a contemporaneous ∼15% upsurge of PM2.5 concentrations over large areas in southern China. We find that the pollution transfer that resulted from a shift in emissions was of a high likelihood caused by a natural gas shortage in the south due to the coal-to-gas transition in the north. The overall shortage of natural gas greatly jeopardized the air quality benefits of the coal-to-gas strategy in winter 2017 and reflects structural challenges and potential threats in China's clean-energy transition. [ABSTRACT FROM AUTHOR]

KORUS-AQ was an international cooperative air quality field study in South Korea that measured local and remote sources of air pollution affecting the Korean Peninsula during May–June 2016. Some of the largest aerosol mass concentrations were measured during a Chinese haze transport event (24 May). Air quality forecasts using the WRF-Chem model with aerosol optical depth (AOD) data assimilation captured AOD during this pollution episode but overpredicted surface particulate matter concentrations in South Korea, especially PM 2.5 , often by a factor of 2 or larger. Analysis revealed multiple sources of model deficiency related to the calculation of optical properties from aerosol mass that explain these discrepancies. Using in situ observations of aerosol size and composition as inputs to the optical properties calculations showed that using a low-resolution size bin representation (four bins) underestimates the efficiency with which aerosols scatter and absorb light (mass extinction efficiency). Besides using finer-resolution size bins (8–16 bins), it was also necessary to increase the refractive indices and hygroscopicity of select aerosol species within the range of values reported in the literature to achieve better consistency with measured values of the mass extinction efficiency (6.7 m 2 g -1 observed average) and light-scattering enhancement factor (f (RH)) due to aerosol hygroscopic growth (2.2 observed average). Furthermore, an evaluation of the optical properties obtained using modeled aerosol properties revealed the inability of sectional and modal aerosol representations in WRF-Chem to properly reproduce the observed size distribution, with the models displaying a much wider accumulation mode. Other model deficiencies included an underestimate of organic aerosol density (1.0 g cm -3 in the model vs. observed average of 1.5 g cm -3) and an overprediction of the fractional contribution of submicron inorganic aerosols other than sulfate, ammonium, nitrate, chloride, and sodium corresponding to mostly dust (17 %–28 % modeled vs. 12 % estimated from observations). These results illustrate the complexity of achieving an accurate model representation of optical properties and provide potential solutions that are relevant to multiple disciplines and applications such as air quality forecasts, health impact assessments, climate projections, solar power forecasts, and aerosol data assimilation. [ABSTRACT FROM AUTHOR]

The winter haze is a growing problem in North China, but the causes are not well understood. The chemistry version of theWeather Research and Forecasting model (WRF-Chem) was applied in North China to examine how PM2.5 concentrations change in response to changes in emissions (sulfur dioxide (SO2), black carbon (BC), organic carbon (OC), ammonia (NH3), and nitrogen oxides (NOx)), as well as meteorology (temperature, relative humidity (RH), and wind speeds) changes in winter. From 1960 to 2010, the dramatic changes in emissions lead to +260% increases in sulfate, +320% increases in nitrate, +300% increases in ammonium, +160% increases in BC, and +50% increases in OC. The responses of PM2.5 to individual emission species indicate that the simultaneous increases in SO2, NH3, and NOx emissions dominated the increases in PM2.5 concentrations. PM2.5 shows more notable increases in response to changes in SO2 and NH3 as compared to increases in response to changes in NOx emissions. In addition, OC also accounts for a large fraction in PM2.5 changes. These results provide some implications for haze pollution control. The responses of PM2.5 concentrations to temperature increases are dominated by changes in wind fields and mixing heights. PM2.5 shows relatively smaller changes in response to temperature increases and RH decreases compared to changes in response to changes in wind speed and aerosol feedbacks. From 1960 to 2010, aerosol feedbacks have been significantly enhanced due to higher aerosol loadings. The discussions in this study indicate that dramatic changes in emissions are the main cause of increasing haze events in North China, and long-term trends in atmospheric circulations may be another important cause since PM2.5 is shown to be substantially affected by wind speed and aerosol feedbacks. More studies are necessary to get a better understanding of the aerosol-circulation interactions. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is a global and persistent contaminant, affecting human health primarily via marine fish consumption. Large anthropogenic releases of Hg to the atmosphere by mining and coal combustion have resulted in a significant perturbation to the biogeochemical cycling of Hg. The magnitude of this perturbation and the relative roles of the ocean and land as sinks for anthropogenic Hg remain unclear. Here we use a 3-D global ocean biogeochemical model to show that surface ocean Hg concentrations have increased fourfold over the last 600 years. We find that anthropogenic Hg enters the ocean's interior predominantly by absorption onto sinking organic matter particulates, which decompose and release Hg at a depth of 500-800 m, implying that the human perturbation is largest in subsurface waters of biologically productive regions. Our model simulation predicts that over the last six centuries half of emitted anthropogenic Hg has accumulated in the oceans and marine sediments. [ABSTRACT FROM AUTHOR]

For the model intercomparison study, MICS Asia phase II, standard air pollutants emission data are provided from published research results (the TRACE-P data set) and other recent work. To provide preliminary information concerning the reliability of the standard emissions data, this inventory was compared with a local emission inventory, EAGrid2000-Japan, which has been developed for detailed analyses with fine grid data resolution for the Japan region. Although these inventories are based upon different estimation methodologies, from the comparative analyses it was found that regional emissions of the standard data are consistent, with differences smaller than 10% for SO2, NO x , NMVOC and CO2, and smaller than 30% for CO and NH3. Differences for all species are smaller than the 95% confidence intervals that were estimated in the research that produced the standard emissions data. Additional information is provided regarding emissions of PM10 and PM2.5, although these did not originate in the TRACE-P data. Furthermore, it was found that the 0.5°×0.5° grid-based emissions from the two inventories match well for NO x , NMVOC, CO, and PM2.5, even though the spatial allocation techniques for the local inventory are much more detailed. For SO2 emissions, the differences in the grid-based inventories are greater. Although some problems still remain, such as diurnal variations that are not considered in the standard emissions data, the intercomparison analysis suggests that the standard emissions data have appropriate properties for atmospheric model simulation. [Copyright &y& Elsevier]

Abstract: China is taking major steps to improve Beijing''s air quality for the 2008 Olympic Games. However, concentrations of fine particulate matter and ozone in Beijing often exceed healthful levels in the summertime. Based on the US EPA''s Models-3/CMAQ model simulation over the Beijing region, we estimate that about 34% of PM2.5 on average and 35–60% of ozone during high ozone episodes at the Olympic Stadium site can be attributed to sources outside Beijing. Neighboring Hebei and Shandong Provinces and the Tianjin Municipality all exert significant influence on Beijing''s air quality. During sustained wind flow from the south, Hebei Province can contribute 50–70% of Beijing''s PM2.5 concentrations and 20–30% of ozone. Controlling only local sources in Beijing will not be sufficient to attain the air quality goal set for the Beijing Olympics. There is an urgent need for regional air quality management studies and new emission control strategies to ensure that the air quality goals for 2008 are met. [Copyright &y& Elsevier]

• Residential BC emissions in rural China at 1×1 km resolution was developed based on field investigation. • Residential combustion of solid fuel in rural China accounted for 51.8% of ground-level BC concentrations annually after dispersion. • 171,000 premature mortalities in China that were attributable to exposure to rural residential BC Black carbon (BC) is a significant component of particulate matter (PM) that relates to air pollution, climate forcing, and further implications for public health. BC is predominantly released from the combustion of solid fuels. Combustion of low-quality fuels in rural China may induce severe respiratory and cardiopulmonary health outcomes for residents, which have however been inadequately assessed. One major reason for the limited understanding is the lack of a high-resolution inventory. An improved method of estimating the BC-associated public health burden is needed. This work quantified premature mortalities due to residential BC emissions in rural China. Domestic BC emissions at 1×1 km resolution were compiled based on previous field investigation, which were further configured for air quality simulation. A chemistry transport model, WRF–CMAQ v5.2, was employed for simulating BC concentrations. The consequent premature mortalities were quantified by a BC-specific concentration-response function (CRF) derived from an epidemiological study. Results show that residential combustion of solid fuel in rural China emitted 648.0 Gg (95%CI: 361.0–965.9) BC in 2014, after dispersion, accounting for 51.8% of annual mean ground-level BC concentration in China. Such impact was most severe in North and Northeast China, and the Sichuan Basin. The further investigation estimated 171,000 (95%CI: 69,000–387,000) premature mortalities that were attributable to exposure to rural residential BC. These findings reveal the major contribution of rural residential BC emissions to air pollution formation and public health impacts. Our findings are anticipated to provide useful information for enacting the next-stage environmental strategy for the residential sector in China. [ABSTRACT FROM AUTHOR]

This work evaluates the effectiveness of on-road primary particulate matter emission reductions that can be achieved by long-term vehicle scrappage and retrofit measures on regional and global levels. Scenario analysis shows that scrappage can provide significant emission reductions as soon as the measures begin, whereas retrofit provides greater emission reductions in later years, when more advanced technologies become available in most regions. Reductions are compared with a baseline that already accounts for implementation of clean vehicle standards. The greatest global emission reductions from a scrappage program occur 5 to 10 years after its introduction and can reach as much as 70%. The greatest reductions with retrofit occur around 2030 and range from 16-31%. Monte Carlo simulations are used to evaluate how uncertainties in the composition of the vehicle fleet affect predicted reductions. Scrappage and retrofit reduce global emissions by 22-60% and 15-31%, respectively, within 95% confidence intervals, under a midrange scenario in the year 2030. The simulations provide guidance about which strategies are most effective for specific regions. Retrofit is preferable for high-income regions. For regions where early emission standards are in place, scrappage is suggested, followed by retrofit after more advanced emission standards are introduced. The early implementation of advanced emission standards is recommended for Western and Eastern Africa. [ABSTRACT FROM AUTHOR]

Abstract: Estimates of future emissions are necessary for understanding the future health of the atmosphere, designing national and international strategies for air quality control, and evaluating mitigation policies. Emission inventories are uncertain and future projections even more so, thus it is important to quantify the uncertainty inherent in emission projections. This paper is the second in a series that seeks to establish a more mechanistic understanding of future air pollutant emissions based on changes in technology. The first paper in this series (Yan et al., 2011) described a model that projects emissions based on dynamic changes of vehicle fleet, Speciated Pollutant Emission Wizard-Trend, or SPEW-Trend. In this paper, we explore the underlying uncertainties of global and regional exhaust PM emission projections from on-road vehicles in the coming decades using sensitivity analysis and Monte Carlo simulation. This work examines the emission sensitivities due to uncertainties in retirement rate, timing of emission standards, transition rate of high-emitting vehicles called “superemitters”, and emission factor degradation rate. It is concluded that global emissions are most sensitive to parameters in the retirement rate function. Monte Carlo simulations show that emission uncertainty caused by lack of knowledge about technology composition is comparable to the uncertainty demonstrated by alternative economic scenarios, especially during the period 2010–2030. [Copyright &y& Elsevier]

Abstract: We present global emission projections of primary particulate matter (PM) from exhaust of on-road vehicles under four commonly-used global fuel use scenarios from 2010 to 2050. The projections are based on a dynamic model of vehicle population linked to emission characteristics, SPEW-Trend. Unlike previous models of global emissions, this model incorporates more details on the technology stock, including the vehicle type and age, and the number of emitters with very high emissions (“superemitters”). However, our estimates of vehicle growth are driven by changes in predicted fuel consumption from macroeconomic scenarios, ensuring that PM projections are consistent with these scenarios. Total emissions are then obtained by integrating emissions of heterogeneous vehicle groups of all ages and types. Changes in types of vehicles in use are governed by retirement rates, timing of emission standards and the rate at which superemitters develop from normal vehicles. Retirement rates are modeled as a function of vehicle age and income level with a relationship based on empirical data, capturing the fact that people with lower income tend to keep vehicles longer. Adoption dates of emission standards are either estimated from planned implementation or from income levels. We project that global PM emissions range from 1100 Gg to 1360 Gg in 2030, depending on the scenario. An emission decrease is estimated until 2035 because emission standards are implemented and older engines built to lower standards are phased out. From 2010 to 2050, fuel consumption increases in all regions except North America, Europe and Pacific, according to all scenarios. Global emission intensities decrease continuously under all scenarios for the first 30 years due to the introduction of more advanced and cleaner emission standards. This leads to decreasing emissions from most regions. Emissions are expected to increase significantly in only Africa (1.2–3.1% per year). Because we have tied emission standards to income levels, Africa introduces those standards 30–40 years later than other regions and thus makes a remarkable contribution to the global emissions in 2050 (almost half). All Asian regions (South Asia, East Asia, and Southeast Asia) have a decreasing fractional contribution to global totals, from 32% in 2030 to around 22% in 2050. Total emissions from normal vehicles can decrease 1.3–2% per year. However, superemitters have a large effect on emission totals. They can potentially contribute more than 50% of global emissions around 2020, which suggests that they should be specifically addressed in modeling and mitigation policies. As new vehicles become cleaner, the majority of on-road emissions will come from the legacy fleet. This work establishes a modeling framework to explore policies targeted at that fleet. [Copyright &y& Elsevier]

Abstract: Following model evaluation in part I, this part II paper focuses on the process analysis and chemical regime analysis for the formation of ozone (O3) and particulate matter with aerodynamic diameter less than or equal to 10 μm (PM10) in China. The process analysis results show that horizontal transport is the main contributor to the accumulation of O3 in Jan., Apr., and Oct., and gas-phase chemistry and vertical transport contribute to the production and accumulation of O3 in Jul. Removal pathways of O3 include vertical and horizontal transport, gas-phase chemistry, and cloud processes, depending on locations and seasons. PM10 is mainly produced by primary emissions and aerosol processes and removed by horizontal transport. Cloud processes could either decrease or increase PM10 concentrations, depending on locations and seasons. Among all indicators examined, the ratio of provides the most robust indicator for O3 chemistry, indicating a VOC-limited O3 chemistry over most of the eastern China in Jan., NOx-limited in Jul., and either VOC- or NOx-limited in Apr. and Oct. O3 chemistry is NOx-limited in most central and western China and VOC-limited in major cities throughout the year. The adjusted gas ratio, AdjGR, indicates that PM formation in the eastern China is most sensitive to the emissions of SO2 and may be more sensitive to emission reductions in NOx than in NH3. These results are fairly consistent with the responses of O3 and PM2.5 to the reductions of their precursor emissions predicted from sensitivity simulations. A 50% reduction of NOx or AVOC emissions leads to a reduction of O3 over the eastern China. Unlike the reduction of emissions of SO2, NOx, and NH3 that leads to a decrease in PM10, a 50% reduction of AVOC emissions increases PM10 levels. Such results indicate the complexity of O3 and PM chemistry and a need for an integrated, region-specific emission control strategy with seasonal variations to effectively control both O3 and PM2.5 pollution in China. [Copyright &y& Elsevier]

Abstract: The U.S. EPA Models-3 Community Multiscale Air Quality (CMAQ) modeling system with the process analysis tool is applied to China to study the seasonal variations and formation mechanisms of major air pollutants. Simulations show distinct seasonal variations, with higher surface concentrations of sulfur dioxide (SO2), nitrogen dioxide (NO2), and particulate matter with aerodynamic diameter less than or equal to 10 μm (PM10), column mass of carbon monoxide (CO) and NO2, and aerosol optical depth (AOD) in winter and fall than other seasons, and higher 1-h O3 and troposphere ozone residual (TOR) in spring and summer than other seasons. Higher concentrations of most species occur over the eastern China, where the air pollutant emissions are the highest in China. Compared with surface observations, the simulated SO2, NO2, and PM10 concentrations are underpredicted throughout the year with NMBs of up to −51.8%, −32.0%, and −54.2%, respectively. Such large discrepancies can be attributed to the uncertainties in emissions, simulated meteorology, and deviation of observations based on air pollution index. Max. 1-h O3 concentrations in Jan. and Jul. at 36-km are overpredicted with NMBs of 12.0% and 19.3% and agree well in Apr. and Oct. Simulated column variables can capture the high concentrations over the eastern China and low values in the central and western China. Underpredictions occur over the northeastern China for column CO in Apr., TOR in Jul., and AODs in both Apr. and Jul.; and overpredictions occur over the eastern China for column CO in Oct., NO2 in Jan. and Oct., and AODs in Jan. and Oct. The simulations at 12-km show a finer structure in simulated concentrations than that at 36-km over higher polluted areas, but do not always give better performance than 36-km. Surface concentrations are more sensitive to grid resolution than column variables except for column NO2, with higher sensitivity over mountain and coastal areas than other regions. [Copyright &y& Elsevier]

In the last 10 yr, Beijing has made a great effort to improve its air quality. However, it is still suffering from regional coarse particulate matter (PM10) pollution that could be a challenge to the promise of clean air during the 2008 Olympics. To provide scientific guidance on regional air pollution control, the Mesoscale Modeling System Generation 5 (MM5) and the Models-3/Community Multiscale Air Quality Model (CMAQ) air quality modeling system was used to investigate the contributions of emission sources outside the Beijing area to pollution levels in Beijing. The contributions to the PM10 concentrations in Beijing were assessed for the following sources: power plants, industry, domestic sources, transportation, agriculture, and biomass open burning. In January, it is estimated that on average 22% of the PM10 concentrations can be attributed to outside sources, of which domestic and industrial sources contributed 37 and 31%, respectively. In August, as much as 40% of the PM10 concentrations came from regional sources, of which approximately 41% came from industry and 31% from power plants. However, the synchronous analysis of the hourly concentrations, regional contributions, and wind vectors indicates that in the heaviest pollution periods the local emission sources play a more important role. The implications are that long-term control strategies should be based on regional-scale collaborations, and that emission abatement of local sources may be more effective in lowering the PM10 concentration levels on the heavy pollution days. Better air quality can be attained during the Olympics by placing effective emission controls on the local sources in Beijing and by controlling emissions from industry and power plants in the surrounding regions. [ABSTRACT FROM AUTHOR]

The heaviest aerosol pollution day in the historical record of the Yangtze River Delta occurred on 19 January 2007, in which the daily concentration of PM10 reached 512μgm−3 in Shanghai, 463μgm−3 in Suzhou, 354μgm−3 in Hangzhou, and 282μgm−3 in Nanjing. The hourly concentrations of PM2.5 and PM10 reached peak values of 466 and 744μgm−3, respectively, in Shanghai. With visibility <0.6km, the regional haze covered nearly the entire Yangtze River Delta. High ratios of PM2.5/PM10 (61%), SO2/PM10 (0.38) and NO2/PM10 (0.24) were observed. The unusual stagnant dispersion conditions before a cold front played the predominant role in this high pollution episode, with relative humidity (RH) of 88%, both surface and upper-level inversions, as well as low wind speed (<1ms−1). The sulfur oxidation rate (SOR) reached 0.67 and the nitrogen oxidation rate (NOR) reached 0.61, signifying that formation of sulfate and nitrate contributed significantly to the high secondary aerosol concentration of PM2.5. The enrichment factors of As, Cd, and Pb reached 4058, 6971, and 3972, which were 4.45–6.68 times higher than those on good/moderate days. It was demonstrated that emissions from anthropogenic sources, especially stationary sources such as power plants, industrial boilers, and furnaces, were the major contributors to the heaviest aerosol pollution in the delta. More attention should be paid to the increases in emissions and the higher occurrence of haze days that have accompanied the rapid development of the economy in the Yangtze River Delta. [Copyright &y& Elsevier]

An intensive field study was conducted in Sumatra, Indonesia, during a peat fire episode to investigate the physical and chemical characteristics of particulate emissions in peat smoke and to provide necessary data for source- receptor analyses. Ambient air sampling was carried out at three different sites located at varying distances from the peat fires to determine changes in mass and number concentrations of PM2.5 and its chemical composition (carbonaceous and nitrogenous materials, polycyclic aromatic hydrocarbons, water-soluble inorganic and organic ions, and total and water-soluble metals). The three sites represent a rural site directly affected by the local peat combustion, a semirural site, and an urban site situated downwind of the peat fires. The mass concentration of PM2.5 and the number concentration of airborne particles were as high as 1600 µg/m³ and 1.7 × 105 cm-3, respectively, in the vicinity of peat fires. The major components of PM2.5 in peat smoke haze were carbonaceous particles, particularly organic carbon, NO3-, and SO42-, while the less abundant constituents included ions such as NH4+, NO2-, Na+, K+ organic acids, and metals such as Al, Fe, and Ti. Source apportionment by chemical mass balance receptor modeling indicates that peat smoke can travel long distances and significantly affect the air quality at locations downwind. [ABSTRACT FROM AUTHOR]

Abstract: We develop a source-specific high-resolution emission inventory for the Shandong region of eastern China for 2000 and 2020. Our emission estimates for year 2000 are higher than other studies for most pollutants, due to our inclusion of rural coal consumption, which is significant but often underestimated. Still, our inventory evaluation suggests that we likely underestimate actual emissions. We project that emissions will increase greatly from 2000 to 2020 if no additional emission controls are implemented. As a result, PM2.5 concentrations will increase; however O3 concentrations will decrease in most areas due to increased NO x emissions and VOC-limited O3 chemistry. Taking Zaozhuang Municipality in this region as a case study, we examine possible changes in emissions in 2020 given projected growth in energy consumption with no additional controls utilized (BAU), with adoption of best available end-of-pipe controls (BACT), and with advanced, low-emission coal gasification technologies (ACGT) which are capable of gasifying the high-sulfur coal that is abundant in China. Emissions of NH3 are projected to be 20% higher, NMVOC 50% higher, and all other species 130–250% higher in 2020 BAU than in 2000. Both alternative 2020 emission scenarios would reduce emissions relative to BAU. Adoption of ACGT, which meets only 24% of energy service demand in Zaozhuang in 2020 would reduce emissions more than BACT with 100% penetration. In addition, coal gasification technologies create an opportunity to reduce greenhouse gas emissions by capturing and sequestering CO2 emissions below ground. [Copyright &y& Elsevier]

Urban development in the mega-cities of Asia has caused detrimental effects on the human health of its inhabitants through air pollution. However, averting these health damages by investing in clean energy and industrial technologies and measures can be expensive. Many cities do not have the capital to make such investments or may prefer to invest that capital elsewhere. In this article, we examine the city of Shanghai, China, and perform an illustrative cost/benefit analysis of air pollution control. Between 1995 and 2020 we expect that Shanghai will continue to grow rapidly. Increased demands for energy will cause increased use of fossil fuels and increased emissions of air pollutants. In this work, we examine emissions of particles smaller than 10 μm in diameter (PM10), which have been associated with inhalation health effects. We hypothesize the establishment of a new technology strategy for coal-fired power generation after 2010 and a new industrial coal-use policy. The health benefits of pollution reduction are compared with the investment costs for the new strategies. The study shows that the benefit-to-cost ratio is in the range of 1–5 for the power-sector initiative and 2–15 for the industrial-sector initiative. Thus, there appear to be considerable net benefits for these strategies, which could be very large depending on the valuation of health effects in China today and in the future. This study therefore provides economic grounds for supporting investments in air pollution control in developing cities like Shanghai. [Copyright &y& Elsevier]