The air in Beijing: 2010 and 2006

U.S. Embassy's Beijing Air tweets: Crazy bad air

AP reports:

Pollution in Beijing was so bad Friday the U.S. Embassy, which has been independently monitoring air quality, ran out of conventional adjectives to describe it, at one point saying it was "crazy bad."

The embassy later deleted the phrase, saying it was an "incorrect" description and it would revise the language to use when the air quality index goes above 500, its highest point and a level considered hazardous for all people by U.S. standards...

While the US Embassy's numbers for Friday November 19 reflected an AQI or API (air quality or air pollution index) of 500, China's own Ministry of Environmental Protection recorded an API of only 313.

There are a few reasons for the discrepancy. One cannot discount what is technically known as "telling lies", but another reason is that while the U.S. Embassy measures the air quality at the Embassy just off the capital's Third Ring Road, the official Chinese statistics are calculated as an average of numbers from several measurement stations, most of which are far away from downtown Beijing with its cars and coal-burning central heating plants.

The Ministry of Environmental Protection's numbers look much better

As a historical reference, on December 12, 2006, Danwei published the following:

Beijing's air pollution index is off the charts right now. Literally. Highest ever on record.

China's State Environmental Protection Administration (SEPA) has a pollution rating scale that measures up to 500. I don't think it's ever reached that level before. 25 is safe. 200 is a bad day for Beijing. The average for the last 24 hours has been above 500.

The Ministry of Environmental Protection's website is not transparent about its methods for calculating its numbers, and it seems there is no publicly accessible way to compare the numbers from 2006 with the numbers from the last week.

In 2008, Steven Q. Andrews writing in The Wall Street Journal noted the following:

From 1998 to 2005, the same seven stations -- located in the city center -- were used to measure air quality. These stations monitored areas with different characteristics, including high traffic areas, plus residential, commercial and industrial districts. In 2006, however, just as international scrutiny on China's air quality was increasing, two stations monitoring traffic were dropped from the city API calculations, while three additional stations in less polluted areas were added.