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Barisal, situated in the Barisal Division of southern Bangladesh, occupies a strategic position within the Ganges-Brahmaputra-Meghna delta system, approximately 120 kilometers from the Bay of Bengal. This riverine city lies at an elevation of just 1-3 meters above sea level, making it exceptionally flat and prone to waterlogging, with its urban fabric intricately woven around numerous khals (canals) and the Kirtonkhola River that bisects the settlement. Barisal functions as a crucial regional hub connecting the coastal districts with the interior, characterized by a distinct urban-rural gradient where densely packed neighborhoods transition abruptly into expansive agricultural zones dominated by rice paddies and fish farms. The surrounding landscape consists entirely of alluvial plains with no natural topographic barriers, allowing pollutants to disperse widely but also facilitating the accumulation of emissions during stagnant conditions. Proximity to major waterways means river vessel traffic contributes significantly to local air pollution, while the city's position within Bangladesh's southern agricultural belt exposes it to seasonal biomass burning from crop residues. The flat terrain and high humidity create conditions where pollutants like brick kiln smoke and road dust linger near ground level, exacerbated by the city's role as a processing center for the region's fish harvest, which adds industrial-scale emissions to the mix.

Barisal's air quality follows a pronounced seasonal rhythm dictated by the tropical wet-and-dry climate, with pollution peaking dramatically during the cool, dry winter months from November through February. During this period, temperature inversions become frequent as cool air traps pollutants near the ground, while reduced rainfall allows brick kiln emissions, vehicle exhaust, and road dust to accumulate unabated. The northeast monsoon brings dry winds that actually worsen pollution by transporting agricultural residue smoke from surrounding fields into the city, creating hazardous haze conditions that sensitive groups like children, elderly residents, and those with respiratory conditions should avoid by limiting outdoor activity, especially during morning hours when fog combines with pollutants. From March to May, pre-monsoon heat increases convection that temporarily improves dispersion, though extreme temperatures can make ozone formation a concern. The summer monsoon from June to September brings cleansing rains that wash pollutants from the atmosphere, making this the optimal season for outdoor activities despite high humidity and cyclone risks. October marks a transition as rainfall decreases and pollution begins building again, with residents advised to monitor air quality alerts as domestic biomass burning increases for cooking and heating. Throughout the year, river vessel emissions remain a constant baseline source, fluctuating with agricultural and fish processing cycles.