Intercomparison between satellite‐derived aerosol optical thickness and PM 2.5 mass: Implications for air quality studies

We explore the relationship between column aerosol optical thickness (AOT) derived from the Moderate Resolution Imaging SpectroRadiometer (MODIS) on the Terra/Aqua satellites and hourly fine particulate mass (PM 2.5 ) measured at the surface at seven locations in Jefferson county, Alabama for 2002. Results indicate that there is a good correlation between the satellite‐derived AOT and PM 2.5 (linear correlation coefficient, R = 0.7) indicating that most of the aerosols are in the well‐mixed lower boundary layer during the satellite overpass times. There is excellent agreement between the monthly mean PM 2.5 and MODIS AOT (R > 0.9), with maximum values during the summer months due to enhanced photolysis. The…