Now that the Beijing government is finally publishing their own PM2.5 data on their MEMC website, a lot of smart techies are quickly updating their smartphone pollution apps to include this data. The best I’ve seen is the free China Air Pollution Index (see the images below), and it’s now my instant iPhone favorite because it automatically shows both the US Embassy’s feed as well as the new feed from a particle monitor located in chegongzhuang, somewhere around northwest second ring road. It’s a very impressive app with a lot of tech input as it also:
- Shows air pollution data from all cities in China
- Has amazingly detailed graphs showing trends ranging from 24 hours to 2 years — at blindingly fast speed
I say “let the fun begin” because we can finally have official PM2.5 data to compare to our tried-and-true “unofficial” US Embassy monitor. The most obvious issue for me is the difference between the indexes: the official data uses an hourly API from a national website which combines information from PM as well as SO2 and NO2. This is different from our familiar US Embassy’s AQI, which only uses the PM2.5 data. Also, the recommendations are different at each cutoff — usually stricter using the US data.
Take a look at the image below from yesterday afternoon: the PM2.5 raw data at the US Embassy was better than at the MEMC site (77 vs 93 ug/m3), and yet the US Embassy’s AQI number and their recommendation both were stronger than the MEMC’s. This brings up a great topic for debate — which formula is better than the other formula? And whose criteria should we use: the World Health Organization, or should every country be allowed to make their own criteria?
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