Abstract: Based on average daily PM₁₀ concentrations and meteorological data in the Pearl River Delta (PRD) region in 2006,we analyzed the variation characteristics of PM₁₀ concentrations,and identified the major PM pollution processes by using a Matlab wavelet tool.Coupled with GDAS meteorological data and PM₁₀ observations from four representative sites,the characteristics of back trajectory air masses and regional transport of PM₁₀ mass concentrations during heavy pollution incidents were analyzed by using the HYSPLIT v4.9 pollutant dispersion model.The relationships between PM₁₀ mass concentrations on days meeting the standard and days not meeting the standard,as well as conventional meteorological features including wind speed,relative humidity,average temperature and average pressure,were further compared and discussed.The results show that the air masses leading to PRD regional heavy PM pollution mainly came from northeastern continental and coast areas.Local emissions and regional transport between cities were the major causes of the PM pollution processes.Low and calm wind and relative higher ground average pressure were the major meteorological conditions that had influence over the PM₁₀ pollution in the PRD region.