Expert: China’s Pollution Waves can be Predicted by Key Weather Conditions

Expert: China’s Pollution Waves can be Predicted by Key Weather Conditions
Dec 30, 2015 By eChinacities.com

Editor’s Note: China’s metrological organizations have begun to predict severe pollution waves ahead of time. Weather and environment expert Ma Xuekuan was interviewed by the Chinese media on what metrological conditions he looks for when predicting a pollution wave. Ma says that cold, calm, and humid weather are the worst for pollution.

“The presence of emissions does not mean that there is smog every day. Weather conditions matter,” said Ma Xuekuan, chef metrological forecaster at the China Metrological Administration’s environmental center. Ma said that polluting emissions cause haze, but metrological conditions affect it as well.

Ma said that Beijing, Tianjin, and Hebei have experienced four severe waves of pollution this winter. Usually the area only experiences two waves of pollution per year that last five days each, “two days longer than the waves lasted this year.”

Particles Accumulate in Cold Air

Three weather conditions have added to the frequent haze in 2015. First of all, the air is not as cold as usual. Cold air and wind diffuse pollutant particles. Ma said that this winter has been significantly warmer than last winter. The periods of cold air this year have been both weak and brief. “Such conditions are conducive to the accumulation of pollution particles,” said Ma.

There also have been less windy days this winter. National Climate Center chief climate monitoring expert Zhou Bing said that since the beginning of this winter, Beijing, Tianjin and Hebei have experienced average winds of 1.8 meters per second, which is 10 percent weaker than winds during the same period last year.

Atmospheric Stability

Second, is atmospheric stability: stable conditions during a clear and calm night will cause pollutants to become trapped near ground level. In times of atmospheric instability, the weather is more varied, and pollutants are better dispersed.

The atmosphere can also be divided into layers called strata. In an instable atmosphere, the pollutants are able to reach higher strata and are therefore dispersed. Ma said that in Beijing in the winter, pollutants reach 550 meters into the atmosphere, but reach 1050 meters during other times of the year. Therefore, pollutants do not disperse as well in Beijing in the wintertime.

Humidity Helps Haze

Third, humidity affects pollutants, creating a chemical reaction which results in PM2.5 swells. Ma pointed out that thick haze forms rapidly in humid weather.

Ma believes that real-time monitoring of weather conditions can led to the accurate forecasting of pollution waves and early warnings for heavy pollution.

Source: The Paper

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Keywords: China pollution pollution waves in China

3 Comments

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Guest2503130

Wow, aren't you smart Sherlock?! This simply lets pollution off the hook by making it sound that smog is more influenced by weather than by the intensity of its actual sources.

Jan 03, 2016 07:55 Report Abuse

bill8899

Do particles accumulate in cold air, or does cold air diffuse the particles?

Jan 03, 2016 00:47 Report Abuse

sorrel

Relying on the weather is cheap solution and it makes pollution someone else's problem. Maybe a few strategically placed fans will move the problem away from Beijing, because we all know, out of sight means out of mind.

Dec 31, 2015 01:35 Report Abuse