In a country which houses 21 of the world's 100 most polluted cities, outcry over official underplaying of pollution is escalating as residents refuse to take government readings of the problem at face value.
Beijing environmental authorities claim that the capital had already reached its annual 'blue sky days' target for 2011, stating that the air quality this year was better than the Olympic year of 2008.
The latest claims have been met with derision online, amid fears among the population that the government is covering up pollution.
On Sunday the state-run Xinhua News Agency reported that Beijing has enjoyed 274 days of 'blue sky' in 2011.
"Beijing has seen an overall decline in the concentration of various pollutants in 2011" said Zhuang Zhidong, deputy director of Beijing's Municipal Environmental Protection Bureau (BJEPB).
The article conceded that the capital also experienced "several days of poor air quality as a result of bad weather conditions." The BJEPB blamed factors including weaker winds and a rise in humidity for failing to disperse atmospheric pollutants.
Netziens on China's most popular micro-blogging site Sina Weibo have met the latest claims with scorn. "Is today April Fool's Day?" asked one Weibo-user, cited in the Hong Kong-published South China Morning Post. "I suggest that Beijing's environmental authorities wear sunglasses with a blue lens, so that every day is a blue sky day!" "The BJEPB has lost credibility with the Chinese people," the Beijing-based environmental consultant Steven Q. Andrews tells IPS over email. "Ozone and fine particulate are monitored by the government but not publicly reported. Significant concerns have also been raised regarding the accuracy of BJEPB monitoring.
"For example, previously the BJEPB shut down monitoring stations set up to measure roadway pollution and claimed that air quality had improved as a result even though the concentrations of various pollutants would have increased if the monitoring locations had remained consistent.
"By not reporting fine particulate the government is able to claim that air quality has improved in the capital, even when the severity of air pollution and the health impacts have been increasing," he adds.
Earlier this month Beijing's population was in uproar over large discrepancies between the BJEPB's official air quality readings and the U.S. embassy's monitor readings. The embassy produces its own pollution readings and transmits them online and via Twitter.
The disparity between the readings lies in the size of the airborne particulates measured. Official readings measure the larger airborne particulate matter known as PM10, while the U.S. embassy measures the smaller PM2.5, which are seen as more dangerous to human health because they penetrate deeper into the lungs.
According to a report by Andrews published on the environmental website China Dialogue, officials in Beijing over the last two years have announced that there has been good, or excellent, air quality in the capital almost 80 percent of the time. By contrast, the U.S. embassy measured that over 80 percent of days have had unhealthy levels of pollution.
Increasing public pressure has led to announcements last month that officials are revising air quality evaluation standards. Proposed revisions state that by 2016 cities across China will be required to monitor air by measuring PM2.5.
"Different data are collected by using different monitoring methods. These two methods are not comparable. For PM2.5, we can and do have monitoring data, but this data is not freely available to the public. Publishing data on air quality and environmental quality is a very serious matter,' Du Shaozhong, vice-president of BJEPB tells IPS.
"At present, the public feels that the information published by the government in Beijing is not as good as the U.S. embassy. I think we should improve our information releasing system and create user-friendly methods, such as apps on mobiles.
"We are confident with the information we have released, because we have many air quality watch bureaus and we produce accurate data. Beijing's air quality has gradually improved," Du adds.
On the ground, however, residents see a very different view. In early December skies chocked with pollution coincided with around 700 flights being cancelled out of Beijing airport, blamed by authorities on bad weather.
While the government described the days of gray acrid smog which shrouded the sky as "light pollution", the U.S. embassy read the air as "hazardous" or off the scales.
Fear of the polluted air has led to soaring sales of facemasks, with some stores selling out completely.
According to figures from Taobao Mall, China's largest online marketplace, over 30,000 facemasks were sold on Sunday Dec. 4 alone - the day when the first planes were grounded.
The sales follow previous outrage on blogs last month over the news that China's leaders had apparently been purchasing sophisticated air filters for the Communist Party's leadership compound Zhongnanhai, while simultaneously claiming that the capital does not have a pollution problem.
The costs are high. A World Bank report from 2007 stated that as many as 750,000 people die annually in China from indoor and outdoor exposure to pollution.
"Put government officials and 'experts' to work in the area where the concentration of PM2.5 is the highest, I bet they will be more efficient," posted one user called Fanfanstudio on Weibo.
Another user named Linye Neo wrote simply: "The Hangzhou radio station said Beijing is covered with yellow sand, traffic jams and poisonous air. Beijing has it all." (END)