China tells US to stop reporting Beijing's bad air

A senior Chinese environmental official told foreign embassies on Tuesday to stop publishing their own reports on air quality in China, a clear reference to a popular U.S. Embassy Twitter feed that tracks pollution in smoggy Beijing.

Wu Xiaoqing, a vice environmental minister, told reporters at a briefing in Beijing that only the Chinese government is authorized to monitor and publish air quality information and warned that data from other sources may not be standardized or rigorous.

The U.S. Embassy gives hourly readings of Beijing's air quality via a Twitter feed that has gathered more than 19,000 followers since it was set up in 2009. It uses a more stringent standard for acceptable amounts of pollution than the Chinese government does.

Wu said it isn't fair to judge Chinese air by American standards because China is a developing country. He noted that the U.S. has gradually made its environmental guidelines more stringent over time.

The standard China uses "takes into account the level of our current stage of development," Wu said.

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.

China requires concentrations of fine particulate matter called PM2.5 to be kept below daily averages of 75 micrograms per cubic meter - more than twice as lenient as the U.S. Environmental Protection Agency's standard of 35 micrograms.

PM2.5 - particles less than 2.5 micrometers in size, or about 1/30th the width of an average human hair - are believed to be a health risk because they can lodge deeply in the lungs, and have been linked to increased cardiovascular and respiratory diseases as well as lung cancer.