Rainfall and shifting seasonal winds brought a temporary relief to Dhaka residents in May, dispersing weeks of dense smog and shortly revealing clearer skies over the capital. Yet despite the improvement, air pollution remained a persistent public health concern.
Data from the global air quality monitoring platform IQAir shows that pollution levels in Dhaka stayed well above internationally recommended limits for most of the month, underscoring the capital city's continuing struggle with hazardous air quality.
Experts warn only weather-based improvements cannot solve the Dhaka's worsening pollution crisis, stressing long-term measures to protect public health, the environment and the economy.
Air quality is measured through the Air Quality Index (AQI), which reflects the concentration of major pollutants, including particulate matter, nitrogen dioxide, sulphur dioxide, carbon monoxide and ozone. An AQI below 50 is considered good, while 101-150 is unhealthy for sensitive groups such as children, elderly people and those suffering from respiratory diseases. Levels above 150 are considered unhealthy for everyone.
Another major indicator is PM2.5, tiny airborne particles that can enter deep into the lungs and even reach the bloodstream. Long-term exposure to PM2.5 is linked to respiratory diseases, heart disease, stroke and lung cancer. The World Health Organization (WHO) recommends keeping annual PM2.5 concentrations below 5 micrograms per cubic metre.
An analysis of IQAir data showed that Dhaka experienced its worst air quality during the first half of May. During the first ten days, AQI readings mostly remained between 120 and 150, placing the city in the "Unhealthy for Sensitive Groups" category.
The highest PM2.5 concentration was recorded on May 11, reaching 73.1 micrograms per cubic metre - nearly fourteen times higher than the WHO's recommended limit. Several other days also recorded PM2.5 levels above 50 micrograms per cubic metre.
Air quality improved around mid-May due to rainfall and seasonal winds. Between May 12 and May 16, AQI levels dropped below 100 on several days, while PM2.5 concentrations declined to around 20-30 micrograms per cubic metre. Although still above international safety standards, the improvement offered some relief to city residents.
Experts say rainfall washes dust and pollutants from the atmosphere, while winds help disperse harmful particles. However, the improvement was temporary. Between May 19 and May 22, pollution levels rose again, with AQI climbing above 120 and PM2.5 increasing to around 40-45 micrograms per cubic metre.
The final week of May saw another improvement, with AQI generally remaining between 80 and 100. Despite cleaner air, pollution levels were still several times higher than WHO recommendations.
Experts identify vehicle emissions, brick kilns, construction activities, road dust, industrial pollution and open waste burning as major sources of Dhaka's air pollution.
Dr. Md. Mahfuz Hossain, Assistant Professor of the Department of Public Health and Informatics at Jahangirnagar University, said prolonged exposure to polluted air has become a serious public health concern. He said polluted air can cause breathing difficulties, throat irritation and eye discomfort in the short term, while increasing the risk of serious diseases over time.
He said children, elderly people and those with existing health conditions are among the most vulnerable groups. Air pollution also creates an economic burden by increasing healthcare costs, reducing productivity and contributing to premature deaths.
Professor Dr. Golam Moinuddin of the Department of Urban and Regional Planning at Jahangirnagar University said rapid urbanisation has worsened the situation by reducing natural water bodies and green spaces in the capital.
He stressed the need for more urban forests, water reservoirs, stricter control of emissions and relocation of industries and brick kilns away from Dhaka.
Environmentalists say lasting improvements will require cleaner public transport, better construction dust management, stronger industrial regulations and effective enforcement of pollution control measures.
Although the monsoon season may bring cleaner air, experts caution that seasonal relief is not a permanent solution. Without strong policies and implementation, Dhaka's pollution problem will continue to threaten public health and the city's future.
