Aerosol Layer Properties and their Effect on Optical Depth Relations to PM2.5 Concentrations

To provide reasonable forecasts of near surface PM2.5 levels, it necessary that satellite measurements provide a reasonable estimator of PM2.5 which can be coupled to a transport model Unfortunately this requires that the aerosol be homogeneously mixed and that the extent of the PBL be sufficiently accurate. For example, the IDEA product (Infusing satellite Data into Environmental Applications) used by the EPA relies on a static relationship connecting PM2.5 to MODIS aerosol optical depth (AOD) which relies on a static model of the PBL aerosol height. In this paper, we show that the PBL height is far from static and by taking the variable PBL into account, a far better prediction of PM2.5 from the MODIS (AOD) measurements is obtained.