Abstract: This paper discuss the effect of fine particle(PM2.5) on the visibility
and restablish the relationship between PM2.5 and visibility. In this paper the relative of PM2.5/PM10、size distribution and extinction coefficient is analyed by means of calculations based on the Mie scattering theory
The relativeship was validated by result of measured in Beijing. The study indicated that the pollution of PM2.5 is the main factor that results in visibility dropping
which is significative for clean out pollution of PM2.5 and improving atmospheric visibility.