Impact of emission control on regional air quality: An observational study of air pollutants before, during and after the Beijing Olympic Games

An observational study on trace gases and PM2.5was conducted at three sites in and around Beijing, during the Olympic season from 2007 to 2009. Air quality improved significantly during the Olympic Games due to the special emission control measures. However, concentrations of the primary pollutants and PM were found to have risen significantly after the Games. Although the major O3precursors(NOx and VOCs) were well controlled during the Olympic season, O3was still found to be the highest in 2008, based on the data of ground-based observation. All this information suggests that while control of regional emissions for the Beijing Olympic Games did improved the air quality in Beijing, more eforts will be needed for the continuous improvement of regional air quality, especially for significant reductions of O3and fine particulate pollution, and not only in Beijing, but also in the Beijing-Tianjin-Hebei region.