Environmental effects of the recent emission changes in China: implications for particulate matter pollution and soil acidification

Driven by a rapid increase of energy consumption and emerging pollution control policies, air pollutant emissions have changed dramatically in China during 2005-2010. This study developed a multi-pollutant emission inventory, and used the community multi-scale air quality (CMAQ) modeling system to evaluate the impact of the emission changes on particulate matter pollution and soil acidification. During 2005-2010, the emissions of SO2, PM10 and PM2.5 decreased by 14.9%, 15.1% and 11.7%, respectively. In contrast, the emissions of NOX, NMVOC and NH3 increased by 33.8%, 21.0% and 10.4%, respectively. The emission trends differed notably in different regions. Driven by emission changes, PM2.5 concentrations decreased by 2-17 mu g m(-3) in most of the North China Plain, the Yangtze River Delta and the Pearl River Delta, while increasing by 4.5-16 mu g m(-3) in most of the Sichuan Basin and Eastern Hubei. The changes of PM2.5 emissions led to the decline of primary PM2.5 concentrations in most of Eastern China. As an effect solely of emission changes, nitrate concentrations increased across most of China; sulfate concentrations decreased in most of Eastern China, with the largest reduction in the North China Plain, while they increased in the Sichuan Basin and parts of the Pearl River Delta and Eastern Hubei. The concentrations of secondary inorganic aerosols (SIA) and the extinction coefficient increased in most of China, especially in the Sichuan Basin and Eastern Hubei, implying that the NOX and NH3 emissions should be reduced simultaneously in China. Combining the acidification effects of S and N, the exceedance of critical loads decreased across the country, but increased in the Sichuan Basin, the Pearl River Delta and Eastern Hubei, where the soil acidification was the most serious. Different control policies need to be implemented in different regions.