The National Ministry of Environmental Protection recently published the latest Air Quality Index (hereafter AQI) standards for China. According to a 173-day period of inspection from 1st July to 20th December 2011, Dongguan's level of "PM2.5" went above acceptable limits for a period of 9 days. PM2.5 (Particulate Matter 2.5) is known as the smallest and most hazardous airborne pollutant due to its smaller than 2.5 microns diameter making it easily inhaled. Such matter includes all tiny particles or droplets in the air that are 2.5 microns or less in width. Dongguan's Environmental Protection Bureau released the city's PM2.5 pollution data for the first time on Thursday 5th January.
In May 2011 Dongguan was appointed as one of 26 pilot cities for National Air Quality monitoring by the Ministry of Environment Protection. A real-time air quality monitoring assessment was conducted for 2011 spanning from 1st July to 20th December, and benchmarked against the latest national standards.
These latest national AQI standards have not yet been formally implemented across all of China, and are in fact presently only in use in pilot cities. According to inspection statistics, during the 173-day monitoring period, 133 days had "very good weather". Yet when compared with the latest Air Pollution Index (API), it was found that the occasions of what is considered "very good weather" decreased by 22.7%. The API is derived from measurements of Sulfur Dioxide, Nitrogen Dioxide and PM 10 (all particulate matter finer than 10 microns in width) which primarily includes matter released by cars and coal burning. Due to its abundance in cities, PM10 has a far more directly harmful effect on human health than PM2.5.
The AQI strengthen the standards for air quality assessment by adding measures which consider Ozone, Carbon Monoxide and PM2.5. Based on the index of Sulfur Dioxide, Nitrogen Dioxide, PM10, Ozone, Carbon Monoxide and PM2.5, 34 days of the 173-day monitoring period were classified "slightly polluted".
Dongguan's Environmental Protection Bureau said that they have been carrying out pilot monitoring of PM2.5 since 2008, and now have 8 fixed monitoring spots and one flowing-air monitoring vehicle. The Bureau confirmed that they would continue to "[…] report the Air Quality Index including Ozone, Carbon Monoxide and PM2.5 in real time as long as notification from higher authority continued".
(By Stefanie Tan)