Cold air from north to help clear capital's skies

Pollution set to linger in center and south of Beijing-Tianjin-Hebei area

Meteorological conditions that don't favor the dispersal of pollutants are to blame for air pollution in the Beijing-Tianjin-Hebei region, with winds carrying pollutants from other regions, making the situation even worse, authorities said.

While cold air from the north will help clear the pollution on Tuesday, moderate to heavy pollution may linger in cities in central and southern parts of the region for the day, a national joint research center on the causes and control of air pollution said on Monday.

From Friday night, the density of PM2.5, a major air pollutant, in some cities around the Taihang and Yanshan mountains in the region began to climb because of pollutants transported from the south and unfavorable conditions for pollutant dispersal, including high humidity and a stable atmosphere.

The hourly average concentration of PM2.5 in Xingtai and Tangshan in Hebei province reached the heavily polluted threshold first, with the level in Beijing following suit.

As of 8 pm on Sunday, the hourly average concentration in Baoding had peaked at 164 micrograms per cubic meter, the center said in a statement posted online.

Beijing's environmental monitoring authority said the PM2.5 density in the capital reached the heavy pollution level from Sunday afternoon and it remained high during daytime on Monday. The average PM2.5 concentration in the capital at 4 pm Monday was 199 mcg/cubic meter.

"The Beijing-Tianjin-Hebei region has regularly been hit by similar air pollution around the National Day holiday," the joint center said.

It said the Beijing-Tianjin-Hebei region saw its best air quality during the weeklong National Day holiday starting on Oct 1 this year compared with previous years, with heavy air pollution arriving much later.

The center said nitric oxide from local vehicle and industrial emissions and sulfur dioxide from other regions were major contributors to the PM2.5 concentrations. The air quality in the region will improve gradually from north to south on Tuesday thanks to cold air from the north.

But pollution will linger in central and southern parts of the region because of pollutants blown in from elsewhere, it said. The transportation and industrial structures in the Beijing-Tianjin-Hebei region mean the air pollution control situation this fall and winter will remain grim, the center said.

Emissions of nitric oxide and volatile organic compounds, both major contributors to air pollution, remain high in Beijing and Tianjin because of the large number of vehicles in the two cities. The concentration of industrial enterprises in Tangshan and Cangzhou also contributes to high sulfur dioxide emissions, the center said.

According to Beijing's environmental authority, diesel-powered trucks are a major contributor to air pollution in the capital.

As the pollution lingers, the authority has organized inspections at 38 entrances to the capital, with environmental officers inspecting 6,000 such trucks a day on average, finding about 900 with excessive emissions.

"Diesel-powered trucks in the city need to be made environmentally friendly to improve the air quality in Beijing," the authority said on Monday.

"The transformation of industrial, energy and transportation structures in the Beijing-Tianjin-Hebei region cannot be done overnight and is a time-consuming process.

"As pollutant discharges remain high, the air pollution control situation in the region is still grim. We should be resolute but also patient ahead of the coming success of air pollution control work in the region."