The uncertainties of a national, bottom-up inventory of Chinese emissions of anthropogenic SO₂, NO_x, and particulate matter (PM) of different size classes and carbonaceous species are comprehensively quantified, for the first time, using Monte Carlo simulation. The inventory is structured by seven dominant sectors: coal-fired electric power, cement, iron and steel, other industry (boiler combustion), other industry (non-combustion processes), transportation, and residential. For each parameter related to emission factors or activity-level calculations, the uncertainties, represented as probability distributions, are either statistically fitted using results of domestic field tests or, when these are lacking, estimated based on foreign or other domestic data. The uncertainties (i.e., 95% confidence intervals around the central estimates) of Chinese emissions of SO₂, NO_x, total PM, PM₁₀, PM_2.5, black carbon (BC), and organic carbon (OC) in 2005 are estimated to be −14%~13%, −13%~37%, −11%~38%, −14%~45%, −17%~54%, −25%~136%, and −40%~121%, respectively. Variations at activity levels (e.g., energy consumption or industrial production) are not the main source of emission uncertainties. Due to narrow classification of source types, large sample sizes, and relatively high data quality, the coal-fired power sector is estimated to have the smallest emission uncertainties for all species except BC and OC. Due to poorer source classifications and a wider range of estimated emission factors, considerable uncertainties of NO_x and PM emissions from cement production and boiler combustion in other industries are found. The probability distributions of emission factors for biomass burning, the largest source of BC and OC, are fitted based on very limited domestic field measurements, and special caution should thus be taken interpreting these emission uncertainties. Although Monte Carlo simulation yields narrowed estimates of uncertainties compared to previous bottom-up emission studies, the results are not always consistent with those derived from satellite observations. The results thus represent an incremental research advance; while the analysis provides current estimates of uncertainty to researchers investigating Chinese and global atmospheric transport and chemistry, it also identifies specific needs in data collection and analysis to improve on them. Strengthened quantification of emissions of the included species and other, closely associated ones – notably CO₂, generated largely by the same processes and thus subject to many of the same parameter uncertainties – is essential not only for science but for the design of policies to redress critical atmospheric environmental hazards at local, regional, and global scales

Facing challenges of increased energy consumption and related regional air pollution, China has been aggressively implementing flue gas desulfurization (FGD) and phasing out small inefficient units in the power sector in order to achieve the national goal of 10% reduction in sulfur dioxide (SO 2 ) emissions from 2005 to 2010. In this paper, the effect of these measures on soil acidification is explored. An integrated methodology is used, combining emission inventory data, emission forecasts, air quality modeling, and ecological sensitivities indicated by critical load. National emissions of SO 2 , oxides of nitrogen (NO X ), particulate matter (PM), and ammonia (NH 3 ) in 2005 were estimated to be 30.7, 19.6, 31.3, and 16.6 Mt, respectively. Implementation of existing policy will lead to reductions in SO 2 and PM emissions, while those of NO X and NH 3 will continue to rise, even under tentatively proposed control measures. In 2005, the critical load for soil acidification caused by sulfur (S) deposition was exceeded in 28% of the country's territory, mainly in eastern and south-central China. The area in exceedance will decrease to 26% and 20% in 2010 and 2020, respectively, given implementation of current plans for emission reductions. However, the exceedance of the critical load for nitrogen (N, combining effects of eutrophication and acidification) will double from 2005 to 2020 due to increased NO X and NH 3 emissions. Combining the acidification effects of S and N, the benefits of SO 2 reductions during 2005-2010 will almost be negated by increased N emissions. Therefore abatement of N emissions (NO X and NH 3 ) and deposition will be a major challenge to China, requiring policy development and technology investments. To mitigate acidification in the future, China needs a multipollutant control strategy that integrates measures to reduce S, N, and PM. From 2000 to 2005, the area of China suffering acid rain was relatively stable or expanded only slightly in the south (2, 6). That is different from Europe and North America, where decreasing trends in acid deposition and related effects (e.g., recovery of acidified surface waters) are clearly observed (7). The power and transportation sectors are considered the most important sources of emissions and hence of regional air pollution and acidification in China. From 1980 to 2006, Chinese electricity consumption and number of vehicles increased by 10 and 15 times, respectively, much faster than the rise in total energy use. Current Air Pollution Situation and PolicyUnder strong environmental pressure, the Chinese government has targeted the power sector as the most important source of emissions (especially of SO 2 ) endangering regional atmospheric environment from 2006 to 2010, the period of the "Eleventh Five Year Plan" (11th FYP). The 11th FYP set as targets the reduction of national energy intensity (i.e., energy consumption per unit GDP output) and SO 2 emissions of 20% and 10%, respectively, measured in 2010 against 2005 levels. To achieve the targets, se...

Abstract. Emissions of air pollutants in East Asia play an important role in the regional and global atmospheric environment. In this study we evaluated the recent emission trends of sulfur dioxide (SO2), nitrogen oxides (NOx), particulate matter (PM), and non-methane volatile organic compounds (NMVOC) in East Asia, and projected their future emissions up until 2030 with six emission scenarios. The results will provide future emission projections for the modeling community of the model inter-comparison program for Asia (MICS-Asia). During 2005–2010, the emissions of SO2 and PM2.5 in East Asia decreased by 15 and 12%, respectively, mainly attributable to the large-scale deployment of flue gas desulfurization (FGD) at China's power plants, and the promotion of highly efficient PM removal technologies in China's power plants and cement industry. During this period, the emissions of NOx and NMVOC increased by 25 and 15%, driven by rapid increase in the emissions from China due to inadequate control strategies. In contrast, the NOx and NMVOC emissions in East Asia except China decreased by 13–17%, mainly due to the implementation of stringent vehicle emission standards in Japan and South Korea. Under current regulations and current levels of implementation, NOx, SO2, and NMVOC emissions in East Asia are projected to increase by about one-quarter over 2010 levels by 2030, while PM2.5 emissions are expected to decrease by 7%. Assuming enforcement of new energy-saving policies, emissions of NOx, SO2, PM2.5 and NMVOC in East Asia are expected to decrease by 28, 36, 28, and 15%, respectively, compared with the baseline case. The implementation of "progressive" end-of-pipe control measures would lead to another one-third reduction of the baseline emissions of NOx, and about one-quarter reduction of SO2, PM2.5, and NMVOC. Assuming the full application of technically feasible energy-saving policies and end-of-pipe control technologies, the emissions of NOx, SO2, and PM2.5 in East Asia would account for only about one-quarter, and NMVOC for one-third, of the levels of the baseline projection. Compared with previous projections, this study projects larger reductions in NOx and SO2 emissions by considering aggressive governmental plans and standards scheduled to be implemented in the next decade, and quantifies the significant effects of detailed progressive control measures on NMVOC emissions up until 2030.

Direct emissions of air pollutants from the cement industry in China were estimated by developing a technology-based methodology using information on the proportion of cement produced from different types of kilns and the emission standards for the Chinese cement industry. Historical emissions of sulfur dioxide (SO 2), nitrogen oxides (NO X), carbon monoxide (CO), particulate matter (PM) and carbon dioxide (CO 2) were estimated for the years 1990e2008, and future emissions were projected up to 2020 based on current energy-related and emission control policies. Compared with the historical high (4.36 Tg of PM 2.5 , 7.16 Tg of PM 10 and 10.44 Tg of TSP in 1997), PM emissions are predicted to drop substantially by 2020, despite the expected tripling of cement production. Certain other air pollutant emissions, such as CO and SO 2 , are also predicted to decrease with the progressive closure of shaft kilns. NO X emissions, however, could increase because of the promotion of precalciner kilns and the rapid increase of cement production. CO 2 emissions from the cement industry account for approximately one eighth of China's national CO 2 emissions. Our analysis indicates that it is possible to reduce CO 2 emissions from this industry by approximately 12.8% if advanced energy-related technologies are implemented. These technologies will bring co-benefits in reducing other air pollutants as well.

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