Thursday, February 26, 2009

Acid Rain is Affecting a Major Portion of China since Last Few Years

Acid rain caused by worsening air pollution now affects one-third of China’s landmass, threatening soil quality and food safety. In 2005, acid rain hit more than half of the 696 cities and counties under air-quality monitoring, with some cities receiving all of their precipitation as acid rain.

While air quality has improved in some areas of China as a result of adjustments in the nation’s energy structure and stricter vehicle emissions standards, 40 percent of urban air quality remains below even second-grade national standards, reflecting various levels of pollutants. Sulfur dioxide and inhalable particulate matter are the two major acid rain-causing substances.

More than 25 million tons of sulfur dioxide belched from China’s coal-fired power and coking plants last year, double the level deemed safe for the facilities` environmental capacity. The desulfurization facilities in these plants have a combined capacity of 53 million kilowatts, representing only 14 percent of total installed capacity. Shanxi Province in northeastern China, famous for its local coking industry, produced more than 80 million tons of coke (a solid carbon residue used in making steel) in 2005, emitting high levels of sulfurous compounds. Of the more than 680 coking enterprises province-wide, only 65 have applied for environmental protection examination and approval; of these, only 30—or about 5 percent of all coking enterprises—currently meet national sulfur emission standards.

Inhalable particulate matter (PM) is the primary pollutant affecting human health and urban air quality in China. In 2005, 35.8 percent of the nation’s cities suffered from PM pollution at levels below the second-grade national standards; the most polluted regions are northern Shanxi, Inner Mongolia, Ningxia, and southwestern Sichuan provinces. Inhalable PM is caused by emissions of soot (fine black particles composed chiefly of carbon, produced by incomplete combustion of coal, oil, wood, or other fuels) and industrial powders. In 2004, Chinese soot emissions topped 11.8 million tons and industrial powder emissions totaled 9.11 million tons.

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