Impacts of Regional Transport on Particulate Matter Pollution in China: a Review of Methods and Results

China has been suffering serious particulate matter (PM) pollution in recent decades. Local emission and regional transport both contribute to PM pollution. Determining the contributions of local emissions vs. regional transport to PM concentrations is crucial in making effective PM control policies. This paper reviews the recent research on the contributions of regional transport to PM pollution in four regions in China, i.e., the northern China, eastern China, southern China, and the western China, respectively. The major findings include (1) HYSPLIT is the most popular methods in studies in all regions and often is used in combination with the CA, PSCF, and CWT techniques to investigate the transport pathways and source origins; (2) during the relatively polluted period, transport contributes over 50% of the PM concentrations in Beijing, Shanghai, Hangzhou, Guangzhou, Hong Kong, and Chengdu. Regional transport is important for PM pollution in major cities of China; and (3) regional transport exhibits clear seasonal variations and long term trends. The findings have important implication for emission control programs in these regions.