Characterizing variations in ambient PM2.5 concentrations at the U.S. Embassy in Dhaka, Bangladesh using observations and the CMAQ modeling system

Poor Respiratory Health is a Consequence of Dhaka's Polluted Air: A Bangladeshi Perspective

Dhaka, which is the capital and largest metropolis of Bangladesh, has seen an increase in the number of documented cases of respiratory disorders. Every day in Dhaka city, a remarkable number of patients are being diagnosed with poor respiratory conditions. The majority of these patients have no other severe disease history and mostly need to be exposed to outdoor air to meet their occupational requirements, indicating that the ailment may be associated with polluted air. As this is the most pressing issue that must be addressed in order to safeguard public health, we have made an effort to focus on the current situation surrounding the sources of air pollution in the city. Since this is a viewpoint article, we gathered data from various published articles, national dailies, and international reports generated by WHO, CDC, BBC, or other environmental news/report portals to highlight the public health issue related to respiratory health. Poor respiratory health is one of the main consequences of Dhaka's contaminated air, as determined by our analysis.

Examining the impact of dimethyl sulfide emissions on atmospheric sulfate over the continental U.S

We examine the impact of dimethylsulfide (DMS) emissions on sulfate concentrations over the continental U.S. by using the Community Multiscale Air Quality (CMAQ) model version 5.4 and performing annual simulations without and with DMS emissions for 2018. DMS emissions enhance sulfate not only over seawater but also over land, although to a lesser extent. On an annual basis, the inclusion of DMS emissions increase sulfate concentrations by 36% over seawater and 9% over land. The largest impacts over land occur in California, Oregon, Washington, and Florida, where the annual mean sulfate concentrations increase by ~25%. The increase in sulfate causes a decrease in nitrate concentration due to limited ammonia concentration especially over seawater and an increase in ammonium concentration with a net effect of increased inorganic particles. The largest sulfate enhancement occurs near the surface (over seawater) and the enhancement decreases with altitude, diminishing to 10-20% at an altitude of ~5 km. Seasonally, the largest enhancement of sulfate over seawater occurs in summer, and the lowest in winter. In contrast, the largest enhancements over land occur in spring and fall due to higher wind speeds that can transport more sulfate from seawater into land.