The concentration of suspension particles (SP) in the air is an important indicator for evaluating the quality of the air. In this article an analysis concerning the SP concentration is presented. The ultimate purpose is to assess the effects of meteorological factors, such as wind speed and precipitation, on the SP concentration. The analysis is based on the data collected, at the Yungho Taipei monitoring site of the Environmental Protection Administration of the Executive Yuan of the republic of China, covering the period September 1986 through November 1987. The data consists mainly of hourly measurements of those pollutant and meteorological variables. An empirical nonlinear model with correlated errors relating the SP concentration to wind speed and precipitation are built using the daily means of above variables. From the analysis, it was found that wind speed has greater effect on SP concentration than precipitation. The predicted values of SP concentration based on the fitted model agree quite well with the observed values. Moreover, we also discuss the immediate precipitation scavenging effect on the SP concentration right after a raining period. It shows that only when the precipitation is large enough, it will have significant decreasing effect on SP concentration, and the effect is most significant for about 12 hours after a raining period.