Aerosol mass concentration variations in typical weather conditions during the spring and winter in the Yangtze river Delta region of China

The aerosol mass concentrations of total suspended particles (TSP: particles with diameter < 100 mu m) and particulate matter (PM10 and PM2.5) were studied at three sites (two urban and one rural) in China's Yangtze River Delta (YRD) during the spring and winter of 2009. Aerosol mass concentrations prevalent during four typical weather conditions in the YRD were then analysed. Major events such as dust storms weakened the impact of TSP, PM10 and PM2.5 concentrations on the generation and dissipation of haze. During stable weather conditions such as cold high pressure, the impact of concentrations of TSP, PM10 and PM2.5 on the generation and dissipation of haze strengthened. When aerosol concentrations are low, even if local meteorological conditions remain favourable, mist is likely to be formed instead of haze. When concentrations are high, and local meteorological conditions are favourable, fog/haze conversion occurs.