The statistical analysis of S City Environmental Protection Monitoring Center shows that the number of days with excellent air quality reached 150 days in 2009, 22 days more than in 2008: the average concentration of carbon dioxide, carbon monoxide, nitrogen dioxide and respirable particulate matter decreased by 21 3%, 25 6%, 26 2% and 15 4% respectively compared with 2008
S City extensively carried out environmental protection publicity, which strengthened the citizens' ecological concept and environmental awareness
 This is due to the relevant measures continuously taken by the municipal government to control air pollution in recent years