With just three weeks to go before the opening ceremony of the Summer Olympics, the blue sky which had been seen over the Bird’s Nest National Stadium in Beijing recently, was giving way to smog again.
The Beijing Ministry for Environmental Protection was still showing data from Thursday (July 17) when the Chinese Air Pollution Index (API) showed a reading of API 77. This figure is valid up until 1200 local (0300 GMT), but the air quality at 0800 local time (0000 GMT) on Friday (July 18) was visibly much worse than the day before, when a blue sky could be seen over the Bird’s Nest.
API 77 is grade 2 in the Chinese system, meaning “comparatively good”, and counts as a “blue sky day” in Beijing. On Friday, the sky was dull at 0800gmt just before it started to pour with rain in Beijing, with the temperature at 27 degrees and 78 percent humidity.
Check out the air quality around the Olympic Green almost live in this video footage here
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What is the API measured with or compaired to ???
- Posted by wayne allanWhat is the Chinese air pollution scale and where can it be found?
What we find interesting is less the API and more the discrepancy between the API’s considered blue sky days
- Posted by Claire Watsonand our daily smogwatch videos. The Air Pollution Index (API) measures suspended particulates with a size smaller than 10 micrometres and they have the ability to penetrate deeply into the lungs. Depending on their source and the existing meteorological conditions, RSP can be made up of a number of different constituents. The problem is that the Chinese API is measured differently and so is nigh impossible to compare to other international standars, the chinese one is not a composite index but reflects the concentration of one of the three reported pollutants — total suspended particles (TSP), sulfur dioxide (SO2) and nitrous oxides (NOx). In Beijing the API of the pollutant with the highest API is reported for all of Beijing. The scale can be found on the government website http://english.sepa.gov.cn. Grade 1 and 2 are blue sky days. The WHO guidelines are measured differently. Their interim target is 150 mcg/m3, which China agreed to in 2005. But the more recent WHO prefered air quality guideline is only 50 mcg/m3.
This is an inofficial table for Converting the PRC Air Pollution Index for TSP to A Concentration in Micrograms Per Cubic Meter
API 50 100 200 300 400 500
TSP 120 300 500 625 875 1000
China-pollution.com also has more