The US embassy in Beijing regularly posts automated air quality measurements at @beijingair on Twitter. On 18 November 2010, the feed described the PM2.5 measurement as "crazy bad" after registering a reading in excess of 500 for the first time. This description was later changed to "beyond index", a level which recurred in February, October, and December 2011. (source: Pollution in China, wikipedia.org)
In June 2012, following strongly divergent disclosures of particulate levels between the Observatory and the US Embassy, Chinese authorities asked foreign consulates to stop publishing "inaccurate and unlawful" data. Since then, more and more organizations started setting up their PM2.5 monitoring stations across China. aqicn.org as part of waqi.info, has been posting hourly air quality index data in China to the public.
China Air Quality Index (AQI) Search Engine is developed by and hosted at the Center for Geographic Analysis at Harvard University, to retrieve as many air quality measurements as possible from the major sources and re-organize the data for environment research uses.
Data available on this site has been collected since February 7, 2014.
The data is made available for public use as provided by the owners and operators of the monitoring equipment, and presented by waqi.info and aqicn.org websites. This collection of data represents only a sampling of the air quality measurements recorded at the sources. It is provided with no warranty *for academic, non-commercial use only* and with the sole intention of contributing data to scientific analysis by anyone who is interested in the public health consequences of air pollution.