(AP) -- Armed with a device that looks like an old transistor radio, some Beijing residents are recording pollution levels and posting them online. It's an act that borders on subversion.
The government keeps secret all data on the fine particles that shroud China's capital in a health-threatening smog most days. But as they grow more prosperous, Chinese are demanding the right to know what the government does not tell them: just how polluted their city is.
"If people know what their air is like, they are more likely to take action," said Wang Qiuxia, a researcher at local environment group Green Beagle, who shows interested residents how to test pollution on a locally made monitoring machine.
Beijing is frequently cloaked in yellow haze. Buildings a couple of blocks away are barely visible. Still, Beijing's official air quality index records the pollution as "light" - a reading at odds with what many people experience.
A reason for the discrepancy is that the official index does not include the fine particles Wang's group is tracking, PM2.5. Sometimes seen as soot or smoke, PM2.5 is tiny particulate matter - less than 2.5 micrometers in diameter or approximately 1/30th the average width of a human hair - that can result from the burning of fuels in vehicles, power plants and agriculture.
Government agencies did not comment for this report. Experts say the government measures are reducing pollution. The Ministry of Environmental Protection has announced plans to factor PM2.5 into new air quality standards, beyond the coarser PM10 already measured, but not until 2016. One environmental official was quoted by state media as saying conditions were "not ripe" for the tougher standard as many places would fail.
"The government always has this worry that if they tell the truth, there will be social unrest. But the reality is the reality. Whether you tell the public or not, the danger is still out there," said Feng Yongfeng, a journalist and founder of Green Beagle, whose mission is to raise awareness of environmental problems and help improve China's environment.
What matters now, Feng said, is for people to conduct their own testing "and see the truth right now." Green Beagle is recruiting people around the city to test the air in their homes, neighborhoods, offices and public spaces. It lends the sole monitoring device it possesses for up to a week.
Some residents even set it whirring in the supermarket. In return for lending the PM2.5 detector, Green Beagle gets the readings and posts them on their website.
While the pollution choking China is testament to the country's explosive growth over the last 20 years, so is the current call for greater government transparency - and cleaner air. A new middle class that is increasingly well-traveled and wired to the Internet is turning its attention to quality of life and demanding official accountability.
"Firstly, people on low incomes care about food and clothing. Once food and clothing is no longer a problem, they start to care about the environment and health. Especially the air," said Wang, 23, the Green Beagle activist.
Chinese authorities have squared off against this more assertive middle class on matters ranging from computer censorship to contaminated milk. In August, 12,000 residents in the wealthy northeastern port city of Dalian demonstrated against a chemical plant thought to be unsafe, and the government promised to relocate the plant.
While posting pollution data on the Internet is not specifically illegal, challenging the government can be considered subversive in China where the government zealously guards data it considers sensitive. In the past, people have been jailed for leaking government economic data ahead of the release date.
The battle over Beijing's air seemed to take off this fall amid a run of smog-choked days. Pan Shiyi, a rich celebrity property developer who symbolizes middle-class aspirations, took to China's version of Twitter to repost readings, including PM2.5, from the U.S. Embassy in Beijing that measures air quality from a monitor on its roof and publishes them online every hour.
Last month, an online poll Pan set up asked whether people wanted to see cities introduce PM2.5 standards. Of the 42,188 votes cast, 91 percent wanted to see cities introduce it this year.
The U.S. Embassy air quality readings are often bleaker than the official measure. From noon Sunday to noon Monday - during which hundreds of flights were canceled because of poor visibility at Beijing's airport - embassy readings went from "hazardous" to "beyond index" as pollution exceeded the scale used by the U.S. Environmental Protection Agency. Beijing's Environmental Protection Bureau said pollution was light.
Deborah Seligsohn, an adviser to the Washington-based World Resources Institute, said the government's air quality information isn't timely, since it's an average of the previous 24 hours. But she said the controversy glosses over the strides that China has made in combating pollution and that the United States did not begin measuring PM2.5 until after 2000 and enforcing limits until 2006.
"The government is making major moves to control" the kind of pollution that was typical of London and Los Angeles in the 1950s and 1960s, said Seligsohn, who lives in Beijing. "It's a long process."
Programs are in place to reduce emissions of sulfur dioxide and nitrogen oxide, which come from power plants among other sources and which turn to PM2.5 in the air, Seligsohn said, and there are plans to control emissions of volatile organic compounds, which come from vehicles, by 2015.
Some cities, like Shanghai, have announced they will start using new standards that include PM2.5 soon. The eastern city of Nanjing released PM2.5 statistics last month online, before drawing a rebuke from authorities and pulling the figures.
Overall, the government is losing the perception battle. Tan Liang, a 32-year-old engineer and one of Green Beagle's volunteers, takes readings three times a day around his residential compound, newly built layers of apartment blocks on the outskirts of Beijing's central business district that are home to many young couples.
"If we only have statistics from government agencies whose interests are involved to go on then there won't be any true environmental data," said Tan, who said he was motivated to take part because his wife is five months' pregnant and they live close to an incinerator. "I believe that only by having the citizens involved can we have a true reflection of the real situation."
Green Beagle is encouraging citizens to club together with neighbors and others in their community to buy their own 30,000 yuan ($5,000) PM2.5 monitoring device.
Many feel that is the government's job.
"It is a matter for all people, not just my residential community," said secretary Bai Xiao, 30, strolling in a park with her husband and 5-month-old baby one recent Saturday afternoon as the sun set behind a curtain of smog.
In any case, Wang fears that the government may make independent monitoring of PM2.5 illegal and take retribution. "We are now worried that in the future residents who test the air might be accused of committing an offense," she said on a recent day after delicately placing the device back in its case and handing it to a newly trained citizen.
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