Although China is not yet a highly industrialized country, China has experienced severe atmospheric pollution due to coal combustion and discharged ca. 16 million ton of sulfur dioxide/year. Coal combustion is the primary contributor to atmospheric pollution, especially so in big cities. Concentration of total suspended particulate matter is usually higher in northern cities than in southern cities and higher in winter than in summer. pH of rainfall in cities, Chongqing and Guiyang, located at south of the Yangtze River is less than 5.6. However, no acid rain has been found in Beijing and Tianjin. Although the formation of acid rain can thus be thought of as dependent on the presence of enough sulfur dioxide, other factors such as alkalinity of airborne particulate matter and atmospheric concentration of gaseous ammonia also play important role. While, in Lanzhou and Beijing where petroleum in-dustry was developed and/or traffic volume was rapidly increased photochemical smog has appeared.
