The calculated reduction of tropospheric nitrogen dioxide (NO2) columns during the 2008 Olympic Games obtained by comparing GOME-2 data with CHIMERE model results. This comparison is used to compensate for atypical meteorological conditions. A reduction of NO2 concentrations of approximately 60% is found above Beijing. The air quality measures were especially effective in the Beijing area, but also noticeable in surrounding cities of Tianjin (30% reduction) and Shijiazhuang (20% reduction).
GOME-2 is an atmospheric instrument on the MetOp satellite, which was developed by ESA in cooperation with EUMETSAT.