As a response to public pressure, Beijing officials have begun to release detailed data on pollution. While there were expectations of the report detailing how bad the air quality was, the first day figures were lower than the data that the US has been collecting over the years. The New Zealand Herald reports:
The initial measurements were low on a day where you could see blue sky. After a week of smothering smog, the skies over the city were being cleared by a north wind.
The readings of PM2.5 particulate matter less than 2.5 micrometers in size or about 1/30th the average width of a human hair were being posted on Beijing’s environmental monitoring center’s website. Such small particulates can penetrate deep into the lungs, so measuring them is considered a more accurate reflection of air quality than other methods.
It is the first time Beijing has publicly revealed PM2.5 data and follows a clamour of calls by citizens on social networking sites tired of breathing in grey and yellow air. The US Embassy measures PM2.5 from a device on its rooftop and releases the results, and some residents have even tested the air around their neighbourhoods and posted the results online.
The reading at noon Saturday was 0.015 milligrams per cubic meter, which would be classed as “good” for a 24-hour exposure at that level, according to US Environmental Protection Agency standards. The US Embassy reading taken from its site on the eastern edge of downtown Beijing said its noon reading was “moderate.” Its readings are posted on Twitter.
Despite the low readings, many are still suspicious of the numbers reported by authorities. The Guardian adds:
Steven Andrews, an environmental consultant who has studied Beijing’s pollution data since 2006, said he was “already a bit suspicious” of Beijing’s PM2.5 data. In the 24 hours to noon Saturday seven of the Beijing monitoring centre’s hourly figures were “at the very low level” of 0.003 milligrams per cubic metre.
“In all of 2010 and 2011 the US embassy reported values at or below that level only 18 times out of over 15,000 hourly values or about 0.1% of the time,” Andrews said. “PM2.5 concentrations vary by area so a direct comparison between sites isn’t possible, but the numbers being reported during some hours seem surpisingly low.”
The Beijing centre says it has six sites that can test for PM2.5 and 27 that can test for the larger, coarser PM10 particles that are considered less hazardous. The center is expected to buy equipment and build more monitoring sites to test for PM2.5.
Beijing is not expected to include PM2.5 in its daily roundups of the air quality any time soon. Those disclosures, for example “light” or “serious”, are based on the amount of PM10, sulfur dioxide and nitrogen dioxide in the air.