In Xian, the capital of Shaanxi province, respiratory diseases have reportedly risen 10 per cent annually over the past several years. In the United States, the Environmental Protection Agency estimates that some 60,000 people die each year from respiratory problems linked to particulate emissions. An average of 14 people die each day from asthma aggravated by air pollution - an increase of 300 percent in the last 20 years. As a regional issue, air pollution is evident as acid rain. As pollution particles from the burning of fossil fuels react with sunlight, oxygen, and moisture in the atmosphere, they are transformed into new compounds.
Sulfur dioxide becomes sulfuric acid, and oxides of nitrogen become nitric acid.
When these airborne acids fall on Earth in the form of precipitation, they can kill fish in lakes and streams, damage forests and crops, and corrode metals. In Europe, the United Nations estimates that nearly one-quarter of total forests have been damaged by acid rain. In Great Britain, the total forest area damaged is well over half. According to China's National Environmental Protection Agency, acid rain generated by emissions from burning coal is said to fall over more than 40 percent of the country. Depletion of the ozone layer is due primarily to emissions of chloroflourocarbons, or CFC's.