Xinhua recently reported that the Chinese Ministry of Environmental Protection released statistics on air quality for the first half of 2014 covering large and mid-sized cities. Only 9 out of the 161 cities that use the new and improved air quality standards met the air quality requirements. For the 166 cities that are still using the old standards, only 105 met the requirements. This represents a 7.1 percent decline. The new air quality standards now include standards for PM10, PM2.5, sulfur dioxide, nitrogen dioxide, carbon monoxide and ozone. The old standards lacked PM2.5, carbon monoxide and ozone. The newly released statistics also showed there was a 2.6 percent decline in the number of “state monitored pollution sources” that met the national requirements for environmental protection controls. There are 3,631 such “pollution sources.”
PM2.5 particles are air pollutants with a diameter of 2.5 micrometers or less, small enough to invade even the smallest airways. These particles generally come from activities that burn fossil fuels, such as traffic, smelting, and metal processing.
Source: Xinhua, August 5, 2014
http://news.xinhuanet.com/local/2014-08/05/c_1111949368.htm