Analysis of CALIPSO satellite imagery for air pollution source identification in Hanoi, Vietnam

Identification of air pollution is a significant task for environmental control, manage, and policy decision. In traditional approach, chemical composition analysis is very costly to be applied frequently and largely, especially in developing countries. This paper proposes the use of CALIPSO satellite image to analyze the aerosol sources, highly linking with particulate matter sources, in Hanoi in the periods from 2016 to 2019. Other datasets including Hanoi land-cover map and the monthly average wind direction from MERRA-2 reanalysis were utilized to explain the spatial distribution of aerosol sources. The result shows that polluted continental/smoke accounted for the largest proportion with 40%, followed by polluted dust, smoke, dust and clean continental with a percentage of 35%, 14%, 6% and 5%, respectively. The monthly variation of the aerosol type shown a high frequency of elevated smoke in March, April and October meanwhile polluted continental/smoke was a peak in the dry season (November to March) and lower in the rainy season (May to September). The aerosol types were observed mostly at high attitude including polluted dust, polluted continental and elevated smoke could be related to long-range transport from other places to Hanoi. This study highlights the potentials of using CALIPSO products for identification of air pollution sources in Vietnam.