Journal Article Ppublish 37 citations
PubMed: 37854171 DOI: 10.1016/j.atmosenv.2023.119587
Characterizing variations in ambient PM 2.5 concentrations at the U.S. Embassy in Dhaka, Bangladesh using observations and the CMAQ modeling system.
Atmos Environ (1994) 296
Authors: Golam Sarwar, Christian Hogrefe, Barron H Henderson, Kristen Foley, Rohit Mathur, Ben Murphy, Shoeb Ahmed
Affiliations
- Center for Environmental Measurement & Modeling, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
- Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
- Department of Chemical Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh.
Abstract
We analyze hourly PM 2.5 (particles with an aerodynamic diameter of ≤ 2.5 μm) concentrations measured at the U.S. Embassy in Dhaka over the 2016 - 2021 time period and find that concentrations are seasonally dependent with the highest occurring in winter and the lowest in monsoon seasons. Mean winter PM 2.5 concentrations reached ~165-175 μg/m 3 while monsoon concentrations remained ~30-35 μg/m 3. Annual mean PM 2.5 concentration reached ~5-6 times greater than the Bangladesh annual PM 2.5 standard of 15 μg/m 3. The number of days exceeding the daily PM 2.5 standard of 65 μg/m 3 in a year approached nearly 50%. Daily-mean PM 2.5 concentrations remained elevated (>65 μg/m 3) for more than 80 consecutive days. Night-time concentrations were greater than daytime concentrations. The comparison of results obtained from the Community Multiscale Air Quality (CMAQ) model simulations over the Northern Hemisphere using 108-km horizontal grids with observed data suggests that the model can reproduce the seasonal variation of observed data but underpredicts observed PM 2.5 in winter months with a normalized mean bias of 13-32%. In the model, organic aerosol is the largest component of PM 2.5, of which secondary organic aerosol plays a dominant role. Transboundary pollution has a large impact on the PM 2.5 concentration in Dhaka, with an annual mean contribution of ~40 μg/m 3.
MeSH
Aerosols
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