Remote sensing measurements of aerosol optical thickness and correlation with in-situ air quality parameters during a biomass burning episode in Southeast Asia

Abstract

Smoke haze related to biomass burning is a recurring environmental problem in Southeast Asia which has affected air quality not only in the source regions, but also in the surrounding areas. Air quality monitoring stations and meteorological stations in the region provide valuable information on the concentrations of criteria pollutants such as sulphur dioxide, nitrogen oxide, carbon monoxide, ozone and particulate mass (PM 10) during the haze episodes. Due to the limited coverage of the air quality monitoring stations, it is difficult to study and monitor the spatial and temporal variability of the smoke haze caused by biomass burning, especially in areas without ground-based instrumentation. As such, in this paper, we combine the standard in-situ measurements of PM 10 with remote sensing imagery obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the Terra and Aqua satellites. The columnar AOT is first derived from MODIS images for regions where PM 10 measurements are available and a correlation between AOT and PM 10 measurements is then established. Based on this empirical correlation, it is also shown that MODIS AOT can be used to estimate air quality categories as defined in the Air Pollutant Index (API) used by Malaysia's Department of Environment (DOE) and the Pollutant Standards Index (PSI) used by Singapore's National Environment Agency (NEA). With this integrated approach, we hope to complement and enhance current capabilities in monitoring air quality during the haze episodes.