No more “blue sky days”

China's second-largest municipality will no longer gauge air quality by the skies as new systems are introduced.

After more than a decade of use, environmental authorities in China’s capital, Beijing, will no longer use the “blue sky” method of gauging air quality. Since 1998, City officials have used a five-grade classification system of air quality, with grade I being the best and grade V being the worst and any grade I or II day being considered a “blue sky day”.

However, the municipal government has deemed this method as unrepresentative and different from the true feelings of the general public. According to the Air Quality Department, in 2011 Beijing enjoyed 286 days of “blue skies”, or 78.4% of the year, although local residents might be quick to judge this figure as optimistic. Last year, pollution frequently reached dangerous levels and caused an increase in health problems on days where the smog was at its worst.

The government will now introduce a more sophisticated PM2.5 system, which refers to fine particulate matter 2.5 microns or less in diameter. Anything falling below the PM2.5 size is considered highly dangerous as the smaller microns can penetrate more deeply into the lungs.

China’s environmental authorities have ordered 74 of China’s most polluted cities to install new PM2.5 monitors, which they hope will help effectively monitor and eventually curtail air pollution in urban environments.

The campaign to reduce emissions has also prompted national legislators to call on Beijing's municipal government to implement emissions taxes for car owners in the city, as well as banning high-emmision vehicles from entering the city, re-opening dedicated cycle lanes and encouraging electric vehicle sales.