Estimates of ground-level aerosol mass concentrations using a chemical transport model with moderate resolution imaging spectroradiometer (MODIS) aerosol observations over East Asia

We estimate ground-level mass concentrations of PM_2.5 and PM₁₀ (particulate matter smaller than 2.5 and 10 μm in diameter, respectively) for 2001 using a global chemical transport model with Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD) retrievals. Our method improves on previous techniques by using a new satellite product (fine-mode fraction (FMF)) and is applied to East Asia, where such an approach has not previously been attempted. We evaluate the method by comparing the PM estimates with the observations from Air Quality System sites and Acid Deposition Monitoring Network sites across East Asia. The spatial patterns of the annual and seasonal means of the estimated PM₁₀ concentrations are in better agreement with the observations than the results of the model alone. The PM_2.5 estimates based on both MODIS AOD and FMF data show considerable improvement relative to those using AOD data alone or simply the model and are in better agreement with the observations at three available sites in Korea and Japan. The greatest improvement is found in the cases where the model significantly underestimates the data. Our best estimates of the annual mean PM_2.5 and PM₁₀ concentrations over East Asia are 14.7 and 71.2 μg m^-3, respectively. However, the uncertainties in our PM_2.5 and PM₁₀ estimates are up to 2.5 and 20 μg m ^-3, respectively.