The Research of Urban Air Pollution Weather Characteristics under the Special Terrain

Based on 2003-2009 air pollution monitoring data in Chongqing city, weather characteristics of pollution events are investigated. Results show that the major pollutant is PM_10,., which has a “Dual Peak and Dual Valley” diurnal fluctuation The pollution weather has obvious seasonal and continuity characteristics and these pollution events mainly occur from late-Autumn to next early spring with persistent period for 2-7 days. The process of the pollution weather has a typical characteristics of atmospheric circulation, which local atmospheric circulations are equipped with low or mean pressure in the lower troposphere and zonal or northwest flows in the upper troposphere, resulting in overcast sky or rain-sunshine. In the process of the pollution weather, local meteorological elements have regular changes which in 24-hour the ground air pressure changes in negative, temperature changes in plus, average relative humidity is between 72% and 85%, the wind speed changes little which keeps 1-2m/s, low-level inversion is evident. When the pollution weather is over, air pressure will pick up obviously, temperature will drop and relative humidity will increase.