Heavy air pollution blanketed 40 cities in China from Thursday to Saturday, including Beijing, Tianjin and Shijiazhuang in Hebei Province, environmental authorities said, adding that it's expected to ease on Sunday.
According to a Ministry of Environmental Protection (MEP) statement sent to the Global Times, due to unfavorable meteorological conditions, heavy air pollution shrouded the Beijing-Tianjin-Hebei region and surrounding areas on Tuesday, which later spread to the central and eastern parts of China.
Langfang in Hebei Province witnessed the most severe pollution on Friday, with the average density of PM2.5, or particles measuring less than 2.5 microns in diameter, reaching 263 micrograms per cubic meter.
"Air pollution may worsen in autumn, but the level is quite unusual," Wang Gengchen, a research fellow from the Institute of Atmospheric Physics at the Chinese Academy of Science, told the Global Times on Sunday.
"The cold air from Siberia has yet to arrive, making atmospheric convection slow and hindering the diffusion of accumulated pollutants," he added.
Straw burning is another reason for the air pollution, an expert surnamed Zhang at the Beijing Meteorological Center, told the Global Times.
According to Zhang, farmers in the northern part of China would burn straw after harvests to fertilize their land.
Based on an MEP statement received by the Global Times on Sunday, straw-burning areas increased to 862 from October 5 to 17 across China, 54 more than the same period last year. Most of the areas were located in northern China.
According to the statement, the government has taken measures to curb straw-burning and reduce air pollution.
A blue alert for air pollution, the lowest of the four-level warning system, was issued on Saturday in Beijing, the city's second alert in October.
The Beijing government's heavy air pollution emergency plan states that the government will implement an odd-even license plate scheme when it raises the pollution alert level to the highest.
"If the air quality continues to deteriorate, the government may launch emergency measures, including closing factories or traffic control," he said.
