Beijing has been shrouded by dense fog since Sunday when the municipal observatory issued a code yellow fog alert saying visibility could drop to as low as 500 meters in some parts of the city. Photo: CFP
Hundreds of flights were stranded at the Beijing Capital International Airport on Monday as the city was besieged by thick smog, which prompted residents to buy respirator masks and deepened concerns over air pollution.
As of 2 pm, 126 flights had been delayed by an hour or longer and 207 were cancelled at the airport. Several highways were temporarily closed as visibility dropped to as low as 500 meters in some parts of the city.
Health experts told the Worker's Daily that in such weather, people should stay inside to avoid inhaling micro-particles in the air, and those who go outside need to wear respirator masks.
Panfeng Household Specials, a store on tmall.com, China's largest B2C marketplace, sold more than 300 respirator masks on Monday specializing in preventing PM2.5 particles at a price of 18 yuan ($2.80) each.
The store told the Global Times that its largest deal on Monday saw 100 of the respirator masks sold to a buyer from Beijing's Chaoyang district.
Another store said it sold more than 120 masks to Beijing customers on Monday, compared to its average number of one per day.
The Municipal Environmental Protection Bureau (MEPB) rated on Monday's air pollution as "moderate."
Zhang Mingying, a meteorological engineer at the Beijing Meteorological Bureau, said that according to their records, smog occurred on average six times a year in the past three decades.
"The current smog is the seventh this year, so we cannot say it is not normal," Zhang told the Global Times.
However, the official accounts were challenged by data released by the US embassy, which measures air quality based on the concentration of particles of 2.5 micrometers or smaller.
Its figures released on Sunday evening showed that air pollution in the city was hazardous to human health with a PM2.5 concentration beyond its top index of 500. Its reading was 356 on Monday afternoon, which was still considered "dangerous."
The embassy said in November that its weather data is meant for internal use, and they use a different gauge from local weather authorities, which still rate air quality by measuring airborne particulates of 10 micrometers or less (PM10).
Ma Jun, the director of the Institute of Public and Environmental Affairs, told the Global Times that PM2.5 particles can easily enter the lungs and blood veins, causing serious lung and cardiovascular diseases.
"Industrial emissions from burning coal, auto exhausts and the burning of household waste are all sources of micro-particles. They are hard to deposit and stay in the air for quite a long time," Ma said.
Since Sunday, the smog has been the most popular topic of discussion on Sina Weibo, a leading microblog service in the country, with more than 4 million posts on the subject.
The Ministry of Natural Resources and Environment added the PM2.5 standard into its newly drafted National Ambient Air Quality Standard, which started its second round of public opinion solicitation last month, but PM2.5 statistics remain unknown to the public.
The Southern Metropolis Daily reported Saturday that the MEPB last week formally rejected demands from Internet users to release Beijing's PM2.5 data. The bureau said the information was just for research purposes and could not be disclosed.
Yu Lingyun, an administrative law professor at Tsinghua University, told the Global Times that it was unreasonable for the MEPB to refuse to make the PM 2.5 data public.
"Disclosing this information does not violate any laws. The data is not a state secret," Yu said. "The public has the right to seek administrative recourse or resort to administrative lawsuits to force the bureau to make the data available."
Ma said that weather authorities should publicize PM2.5 information daily, so that residents could be better prepared for serious air pollution.
Zhang Yuanhang, dean of the College of Environmental Science and Engineering of Peking University, told the Guangzhou Daily that if China adopts the PM2.5 standard, only 20 percent of cities in the country will have acceptable air quality, compared to the 80 percent under the current PM10 rating.
"I think that is one of the reasons behind authorities' hesitation to use the PM2.5 measure," Zhang said.
Meanwhile, other regions, including the provinces of Shandong and Hebei, and Tianjin municipality, have also been hampered by fog.
Ma Xuekuan, a weather forecaster with the National Meteorological Station, told the Xinhua News Agency that he expects the fog to dissipate as a cold front sweeps across the region Thursday.
Yang Jingjie, Mo Ting and Jin Jianyu contributed to this story