Beijing organized the 2008 Summer Olympic Games, and the main goal of the Chinese government regarding this event was to hold a "Green Olympics". A difference-in-differences approach was used to estimate the environmental impact the Olympic Games on air quality improvement in Beijing, compared to improvements in other areas in China. The results indicate that compared to other regions, air quality in Beijing improved for a short period of time. These improvements were largely due to the implementation of several temporary measures, including factory closures and traffic control. However, there is no evidence indicating that the Olympic Games reduced the concentration of sulfur dioxide in Beijing.