Urban Air Quality in China

This page presents urban air quality data collected by city-level environmental protection bureaux around China.

As of July 2000, each city in China has been required to publish an Air Pollution Index (API) measured for the urban region each day. Typically, observations are made of NOx, SO2 and TSP (Total suspended particulates), and in some cases CO and O3. An air pollution index is derived for each of these, based on a scale from 0-500 defined by the State Environmental Protection Agency, and generally only the highest API is published. If all APIs are below 50, then the air is considered clean and no species is specified. Some cities, in particular Beijing and Shanghai, are currently publishing the API for all species measured (e.g. see Beijing Wanbao)

The API are released late afternoon for the current day, and are available immediately. The figures for 42 cities are presented here by plotting circles, with radius proportional to API, coloured by the respective constituent, at the appropriate location. These are then compared with noontime analyses from the Japan Weather Association JWA and with the Geostationary Meteorological Satellite GMS view of the area to provide some meteorological context.

General features:

• High SO2 in coal-burning Northern and Western cities.
• Evidence of wintertime dominance of NOx in more developed Eastern China.
• Dominance of TSP (both natural and anthropogenic sources).
• Cleaner, Southeastern, coastal cities affected by onshore flow.

• Movement of dust episodes very clear - will provide advance warning for campaign
• Evidence of meteorological conditions on the mainland (stagnant air associated with high pressure systems, pollution outflow events, etc.)
• Evidence of anthopogenic influences - e.g., reduced holiday or weekend emissions (a clear Spring Festival Effect seen in late-January).
• Possible confirmation of relative source sizes (?)

Temporal Variations:

• Timeseries of Maximum API for urban areas by region
• Daily concentrations of O3/CO/NO2/SO2/PM10 in Beijing
• Daily concentrations of NO2/SO2/PM10 in Shanghai
• Clippings from the Chinese Press

Spatial Variations:

• Air pollution index (API) plotted on each date below
• Figures should be available each day by 19:00 JST
• GIF-animation of entire period
• Approximate dates at Guam (G), Hong Kong (H) and Yokota (Y) are indicated

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