Beijing's environmental authorities said yesterday that air quality in the capital city in 2011 was better than during the Olympics year of 2008, and that they had already met their target of 'blue sky' days for this year, despite growing public concern that officials are covering up worsening problems of air pollution.
'Beijing has seen an overall decline in the concentration of various pollutants in 2011,' said Zhuang Zhidong, the deputy director of the Beijing Municipal Environmental Protection Bureau.
The city had 274 days of 'grade one or two' air quality, according to a statement posted on the Beijing government's official news portal yesterday. China uses a five-grade classification system to rate its air quality, with one being the best and five the worst. Days graded one or two are considered 'blue sky days'.
Overall air quality in Beijing was better than last year, and there were 22 more days of grade-one air quality than were recorded in 2010, and 11 more than in 2008, when Beijing hosted the Olympics, Zhuang said.
Zhuang admitted that the capital also saw 'several days of poor air quality as a result of bad weather conditions'. Factors such as weaker winds and a rise in humidity can raise the presence of atmospheric pollutants, according to the bureau.
The environment ministry is under pressure to change the way it measures air quality after thick smog blanketed Beijing earlier this month, forcing the cancellation of hundreds of flights and triggering a surge in sales of face masks.
Public anger over heavy pollution has been compounded by official data showing air quality is good, or only slightly polluted, on days with obvious heavy smog that the US embassy rated as 'very unhealthy'.
Beijing authorities use a method known as PM10, focusing on larger air particles. The bureau said that PM10, or particulate matter under 10 micrometres, decreased to 114 micrograms per cubic metre this year, the lowest in four years.
But there have been growing public calls for the government to adopt the tighter PM2.5 standard, which measures much smaller particles that are considered more hazardous to people's health as they penetrate deeper into the lungs.
CCTV anchorwoman Zhang Quanling posted on Sina weibo, a popular microblog site, that it was 'ridiculous' that [the Beijing environmental authorities] never changed their measurements on air pollution. 'They're indulged in self-praise,' she wrote.
Many internet users expressed doubt or anger over the authorities' assessment of the city's air quality.
The Beijing environmental bureau deserves to be described as 'shameless', said one weibo user. Another post read: 'A rubbish government without any credibility.'
'Is today April Fool's Day?' asked another weibo user. 'I suggest that Beijing's environmental authorities wear sunglasses with a blue lens, so that every day is a blue sky day!'
The approximate number of flights that were cancelled due to fog in Beijing between December 4 and December 7