Effects of Southeast Asia biomass burning on aerosols and ozone concentrations over the Pearl River Delta (PRD) region

Recent studies show that the rapid increases' in urbanization and human activities in the PRD region have important impacts on regional air quality. In addition to local anthropogenic emissions which are major driving forces for poor air quality in this region, biomass burning in Southeast Asia has also important contribution on aerosol and ozone concentrations in the PRD region. In this paper, this effect is analyzed by using satellite data, ground measurements and models. MODIS aerosol optical depth (AOD) distribution in March 2006 shows a clear enhancement in AOD between Southeast Asia and the PRD region. With detail wind analysis, two distinguished conditions are classified, i.e., Condition-1 (PRD is under influence of the biomass burning from Southeast Asia) and Condition-2 (PRD is not under influence of the biomass burning from Southeast Asia). The characterizations of aerosol, UV, and ozone in Guangzhou city (located in the PRD region) under these two conditions are analyzed. The analyses suggest that aerosols and CO concentrations are higher in Condition-1 than in Condition-2; while the UV intensity and 03 concentrations are lower in Condition-1 than in Condition-2. This result indicates that in Condition-1. the enhanced aerosol concentrations from the Southeast Asia biomass burning produce reduction of UV intensity, and thus decreases the formation of ozone in Guangzhou. (c) 2008 Elsevier Ltd. All rights reserved.