Abstract: Aerosol number and mass concentrations in rural area at Hefei city were measured simultaneously with home-made aerodynamic particle sizer (APS) and tapered element oscillating microbalance (TEOM). An empirical formulas was developed using multiple regression based on the relationship of number and mass concentration. Mass concentration of PM2.5 was calculated and its percentage in PM10 was also illustrated. Diurnal variations of number and mass concentrations of PM10 were presented and its cause has been discussed, which will provide scientific base for air pollution control strategy and methodology in Hefei city.

Key words: number concentration；mass concentration； number concentration distribution；aerodynamic diameter