Evaluation of Satellite-Based Models in Estimating Surface PM2.5 in Bangladesh

Air quality has always been an important topic to discuss meteorologically, but there has been an emerging focus on the health impacts as time has shown the effects of long-term exposure to poor air quality. The National Science Foundation International Research Experience for Students program collaborated with the State University of New York at Albany, Stanford University, the Bangladesh University of Engineering and Technology, and the University of Dhaka. The goal of this partnership is to analyze the usefulness of low-cost sensors and remote sensing technologies to further the understanding of the air quality issues in Bangladesh. Factors that cause poor air quality in the country include densely populated cities, brick kiln pollution, and waste burning that affects indoors and outdoors. The use of these low-cost sensors and satellite data is crucial to the advancement of developing countries like Bangladesh by providing the public with accurate and reliable data. In this study, the surface mass concentration of PM2.5 was measured, focusing on the inter-city variation of seven major cities in Bangladesh. These seven cities are Dhaka, Rajshahi, Khulna, Sylhet, Barishal, Rangpur, and Chattogram. For each city, the yearly variation of concentration from 2000 to 2022 as well as the seasonal variations were analyzed using the Modern Era Retrospective Analysis for Research and Applicants (MERRA-2). Not only was the overall PM2.5 examined, but the individual components that make up the mass of surface PM2.5 were also measured to better understand which particle affects air quality the most and during which seasons. These particles include sea salt, dust, organic carbon, black carbon, and sulfate. It was found that black carbon, organic carbon, and sulfate concentrations were highest during the winters for each city and Rajshahi had the highest concentrations throughout most of the year. Dust in all cities was the highest during the pre-monsoon season and has the highest concentrations in Dhaka mostly caused by the dense population and unfinished construction. Looking at the annual cycles of PM2.5, organic carbon, and black carbon from 2000-2022 in all cities, there has been an overall gradual increase in all three pollutants with notable spikes in 2009, 2012, and 2018. The seasonal variations reveal that the overall PM2.5 has the greatest concentrations during the winter months although the summer months have seen the greatest variability.