Source apportionment of fine particulate matter in China in 2013 using a source-oriented chemical transport model.

China has been suffering high levels of fine particulate matter (PM). Designing effective PM control strategies requires information about the contributions of different sources. In this study, a source-oriented Community Multiscale Air Quality (CMAQ) model was applied to quantitatively estimate the contributions of different source sectors to PM in China. Emissions of primary PM and gas pollutants of SO, NO, and NH, which are precursors of particulate sulfate, nitrate, and ammonium (SNA, major PM components in China), from eight source categories (power plants, residential sources, industries, transportation, open burning, sea salt, windblown dust and agriculture) were separately tracked to determine their contributions to PM in 2013. Industrial sector is the largest source of SNA in Beijing, Xi'an and Chongqing, followed by agriculture and power plants. Residential emissions are also important sources of SNA, especially in winter when severe pollution events often occur. Nationally, the contributions of different source sectors to annual total PM from high to low are industries, residential sources, agriculture, power plants, transportation, windblown dust, open burning and sea salt. Provincially, residential sources and industries are the major anthropogenic sources of primary PM, while industries, agriculture, power plants and transportation are important for SNA in most provinces. For total PM, residential and industrial emissions are the top two sources, with a combined contribution of 40-50% in most provinces. The contributions of power plants and agriculture to total PM are about 10%, respectively. Secondary organic aerosol accounts for about 10% of annual PM in most provinces, with higher contributions in southern provinces such as Yunnan (26%), Hainan (25%) and Taiwan (21%). Windblown dust is an important source in western provinces such as Xizang (55% of total PM), Qinghai (74%), Xinjiang (59%). The large variation in sources of PM across China suggests that PM mitigation programs should be designed separately for different regions/provinces.