The researchers studied air pollution in Beijing and nearby cities during the 2008 Olympic Games. They measured pollutants like particulate matter, ozone, and NO(x) in June, August, and September. They found that particulates were the main pollutants in the area. During the Olympic and Paralympic Games, pollution levels decreased significantly in Beijing. The surrounding areas also had high levels of pollutants, with NO(x) potentially being transported from Beijing. Ozone pollution was a regional issue in the summer. The monitoring network used in the study helped provide early warnings of air pollution and supported cooperation in controlling pollution between regions.