Beijing releases first PM10 density figures
- By Li Jingrong
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China.org.cn, January 12, 2012
On its micro blog post at 8 a.m. Tuesday, the Beijing Municipal Environmental Protection Bureau stated that some suburban districts of the city appeared to be heavily polluted, the stdaily.com website reported. The post was the first time for the bureau to release the city's highest PM10 density figures.
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Beijing is heavily polluted due to the fog on Jan. 10, 2012. [People's Daily] |
![Beijing is heavily pollute ddue to the fog on Jan. 10, 2012. [People's Daily]](http://images.china.cn/attachement/jpg/site1007/20120112/001fd04cf03a1078afee02.jpg "Beijing is heavily pollute ddue to the fog on Jan. 10, 2012. [People's Daily]")
The bureau added that, with respect to PM10, or particulate matter under 10 microns to measure air quality, some districts' readings were up to seven times higher than others.
Six downtown districts and suburbs in the southeast and southwest of the city saw a rapid PM10 density increase before daybreak, with the highest figure standing at 300-560 micrograms per cubic meter. Beijing's northeast and northwest suburbs were largely unaffected, as illustrated by a PM10 density reading of 30-80 micrograms per cubic meter.
Zhao Yue, an official with the bureau, said that Tuesday's pollution level was obviously “trapezoidal distributed" from north to south, and the boundary of pollution severity is closely linked to fog levels.
"On foggy days, PM2.5 often accounts for a higher proportion of PM10," said Zhao. “Data from the air quality monitoring station located in West District shows that PM10 density was 400 micrograms per cubic meter at 10 a.m., with PM2.5 accounting for more than 70 percent to 300 micrograms per cubic meter."
Tuesday's worst period for visibility was between 6 a.m. and 9 a.m. However, the combination of a cold front and strong winds from the north in the afternoon resulted in improved air quality, which in some areas rose as high as Level 1, the best possible reading for particulate matter in this category.
Beijing's Capital Airport saw 34 flights cancelled with a further 98 delayed Tuesday, due to the fog.
The Beijing Municipal Environmental Protection Bureau opened the environmental monitoring section on its micro blog at the end of last year in order to release daily PM10 figures.
The bureau will soon replace the daily figure with hourly updates, and PM2.5 data will be announced before Spring Festival, which falls on Jan. 23.
According to the soon-to-be released national air quality standards, the daily average PM2.5 density will be set at 75 micrograms per cubic meter.
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