Variation Characteristics of Air Pollutant Concentrations during Typhoon Processes in Fuzhou

The temporal and spatial distribution characteristics of PM₁₀, SO₂ and NO₂ and the influence of meteorological conditions were analyzed based on the hourly observation data of air quality and concurrent meteorological data of 4 typhoon processes in 2005 and 2006 in Fuzhou. The results indicated that the air quality in Fuzhou during typhoon processes was better than sunny days. The concentration of PM₁₀ cut down when there was heavy rain and gale. The elimination of SO₂ was mainly affected by precipitation. The concentration of NO₂ increased abruptly due to the reversion of wind direction and the reduction of wind speed, higher than the concentration in sunny days of the same time. In the center of typhoon, the concentration of PM₁₀ and NO₂ increased for downdraft making against the diffusion of pollutants, while the concentration of SO₂ took little change for the existence of precipitation.