Compare the view from my window this week with a day earlier this fall:
The Chinese news today says northeastern China and parts of the south have been shrouded in a fog that left visibility as low as 100 meters in some places. The reports emphasized the traffic dangers but mentioned air quality as an afterthought: “Air quality in Beijing since Monday has hovered between light- and medium-level pollution.” (Sina.com) However, Beijingers know that we don’t get severe fog without severe smog these days.
The government and media understandably don’t like trumpeting bad news such as terrible air quality, and they are gradually moving towards more open and consistent reporting of air quality in light of the public health risk. For now though, reading the Chinese reports can still leave you a little confused about the actual health risks of the day’s air.
A great source for a second opinion is the air quality index (AQI) from a monitor on the roof of the U.S. Embassy. They keep the monitor officially as a resource for the health of their staff, but make its readings available to the public via a twitter and iPhone feed as a sort of public service. That monitor showed a reading of 305 as of 5 p.m. on December 1, classified as dangerous. For comparison, today’s clearer sky and winds gave a reading of 55 as of 7 p.m., classified as moderate. Unhealthy begins at 150 and 300 is the threshold for dangerous. On the notorious day of “crazy bad” air, it broke 500.
Further reading:
Twittering bad air particles in Beijing
Beijingology 