Hazy outlook

China is home to 16 of the 20 cities rated as having the poorest air quality in the world.

Beijing is on the list. The Chinese capital's average level of particulate matter in the air in 2004 was 89 micrograms per cubic meter (the average in Dallas is 13.8).

Industrial plants emitting soot were the biggest source of China's urban air pollution until a few years ago. But auto exhaust-fed smog is now the chief culprit. From 1995 to 2001, ... Full Story »