Excessive coal use main contributor to smog, expert says

Excessive use of "unclean" energy, not vehicle emissions or the burning of straw, is the main contributor to the country's recurrent smog, a China Youth Daily report quoted an expert as saying on Monday.

Speaking at a symposium organized by the China Association for Science and Technology, Zhang Xiaoye, director of an atmospheric composition committee under the China Meteorological Society, said that though straw burning, fireworks and vehicle emissions contribute to air pollution, "excessive use of 'unclean' energy is the real culprit".

According to the report, Zhang used the term "unclean" energy to refer mainly to coal.

"Coal and other unclean energy sources are the number one contributor to China's smog," he said, adding that vehicle emissions may come second, especially in big cities.

Citing PM2.5 readings recorded in early November, when Beijing hosted the Asia-Pacific Economic Cooperation meeting, Zhang said the figures showed a considerable drop of 35 percent.

He said only 10 percent of the pollution reduction came from the odd-and-even license plate vehicle restrictions, which reduced daily traffic by up to 11.7 million cars, whereas the rest was the result of cuts in coal burning in Beijing's neighboring regions starting from Nov 6.

Many parts of China have been regularly plagued by choking smog since 2013. The situation in North China is particularly serious.

To ensure good air quality for APEC, nearly 4,000 factories in Hebei were ordered to close or curb production during the weeklong meeting.

As a result, the Beijing sky remained blue during APEC despite predictions otherwise, with the daily PM2.5 density in the period falling to 43 micrograms per cubic meter, prompting Chinese netizens to coin the phrase "APEC Blue" to describe the clear sky.

Since the lifting of the bans, Beijing has reported several spells of mild to serious air pollution, with PM2.5 density reaching 224 micrograms per cubic meter in Beijing on Tuesday.