Estimating PM2.5 component concentrations and size distributions using satellite-retrieved fractional aerosol optical depth: Part 1 - Development of Methods

We develop a method that uses both the total column
aerosol optical depth (AOD) and the fractional AOD
values for different aerosol types, derived from Multiangle
Imaging SpectroRadiometer (MISR) aerosol data,
to estimate ground-level concentrations of fine particulate
matter (PM2.5) mass and its major constituents in
eastern and western United States. Compared with previous
research on linking column AOD with groundlevel
PM2.5, this method treats various MISR aerosol
components as individual predictor variables. Therefore,
the contributions of different particle types to
PM2.5 concentrations can be estimated. When AOD is
greater than 0.15, MISR is able to distinguish dust from
non-dust particles with an uncertainty level of approximately
4%, and light-absorbing from non-light-absorbing
particles with an uncertainty level of approximately
20%. Further analysis shows that MISR Version 17 aerosol
microphysical properties have good sensitivity and
internal consistency among different mixture classes.
The retrieval uncertainty of individual fractional AODs
ranges between 5 and 11% in the eastern United States,
and between 11 and 31% in the west for non-dust
aerosol components. These results provide confidence
that the fractional AOD models with their inherent
flexibility can make more accurate predictions of the
concentrations of PM2.5 and its constituents.