A combo photo shows the contrast of the National Stadium (Bird's Nest) in a smoggy day and a clear day in Beijing. (File photo)
(ECNS) -- Air quality in China is generally getting better, but more time is still needed to fundamentally control pollution, scientists and researchers with the Chinese Academy of Sciences said, adding that air in Chinese cities could improve in three to five years.[Special coverage]
Coal-burning, car exhaust fumes and emissions from industrial production are the main causes of smog in Chinese cities, especially in the Beijing-Tianjin-Hebei region, said He Hong, a researcher with the CAS Center for Excellence in Regional Atmospheric Environment.
The number of days with severe air pollution has reduced, however, many city residents said they don't feel air quality is improving.
He said it's because the concentration of pollutant particulates in the air has not decreased enough to be obvious.
In addition, air pollution in the country's central and eastern regions is still severe in fall and winter. The concentration level of PM2.5, hazardous particulate matter with a diameter of 2.5 microns or less, did not decrease remarkably in Beijing during 2016, compared with the previous three years, He said.
Unfavorable weather conditions, including low wind speed and temperature inversion, were external causes of smog, it was added.
According to statistics, the average wind speed during the past 40 years in China's northern region continually decreased by 37 percent. The frequency and speed of the north wind, which is a favorable weather condition for air diffusion, also dropped.
Controlling pollution from coal burning and automobile exhaust fumes will help improve air quality. Wang Jianguo, also a researcher with the academy, said a technology that can reduce the emission of pollutants from coal burning could be used in 13 industrial projects next year.
Wang Zifa, a researcher with the Institute of Atmospheric Physics under the academy, said it has made the world's first integrated air forecast system, which can help related departments improve air supervision and treatment.
