Abstract:Based on the environmental data monitored during the period from January 1, 2006 to December 31, 2010, analysis and evaluation was made of the variation law of the air pollutants in the Suining City by aid of API index method. The results showed that the daily average concentration of PM10 in each functional area is 0.077- 0.123 mg/m3; sulphur dioxide is 0.030 - 0.043 mg/m3; nitrogen dioxide is 0.022 - 0.025 mg/m3 and API is below 100. As for the with - time variation, the overall performance of PM10 pollution in each functional area is as follows: the pollution of the first quarter is relatively serious; the second quarter is the second worst, the fourth quarter is the third worst and the third quarter is the least serious in terms of air pollution. In regard of spatial change, pollution in the southern industrial area (where the Qunkang Printing and Dyeing Mill is located) is relatively heavier; next to it comes the western section of the city (where the Monitoring Station is located) and the Hedong New Area (where the City Administration Center is situated) enjoys the best.enviromental quality. It is suggested that the chief air pollutants in the Suining city are from inhalable particles