AQI shows heavy pollution citywide for first time this year

By Liu Sheng Source:Global Times Published: 2013-1-13 23:48:01

Dense pollution fell on Shanghai over the weekend, marking the first time this year that the Air Quality Index (AQI) breached the heavy pollution threshold citywide, the city's pollution monitoring authority reported Sunday.

The AQI peaked at 222 early Sunday, surpassing the 200 mark that indicates heavy pollution, before falling back later in the day due to rain and heavier wind, according to the Shanghai Environmental Monitoring Center.

Much of the pollution was expected to disperse by Monday.

The pollutant most responsible for the rise in the AQI was PM 2.5, particulate matter 2.5 microns in diameter or smaller, according to Wang Qian, an air quality forecaster with the monitoring center.

"This weekend's pollution is partly caused by the cold front out of northern China, which was also inundated with heavy pollution," Wang told the Global Times.

PM 2.5 is especially dangerous because the size of the particulates allows them to lodge deeply in the lungs, where they can cause or aggravate respiratory illnesses.

The monitoring center suggested that residents check the hourly PM 2.5 readings on its website, rather than the daily readings, which are based on conditions over the previous 24 hours.

The AQI continue to show moderate levels of pollution late Sunday. The hourly PM 2.5 reading had fallen to 24.5 micrograms per cubic meter by 5 pm, down from 223 micrograms per cubic meter at its peak Saturday afternoon, according to the monitoring center.  When the PM 2.5 reading surpasses 150 micrograms per cubic meter in any given hour, residents may want to take precautions.

Some residents were grabbing up face masks that were marketed as being able to filter out pollutants. However, Wang said these masks do nothing for PM 2.5 because the particulates are too fine.

"The masks may help stop larger particles, but the best way to avoid pollution is to keep children, senior citizens and people suffering from heart and respiratory illnesses from spending too much time outside," Wang said.

 



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