Bangladesh

Bangladesh has undergone rapid industrialization and urbanization in recent decades, improving socioeconomic conditions but exacerbating environmental challenges, particularly air pollution. Poor air quality is a pressing national issue, affecting all major cities. There are seven criteria pollutants considered in determining the ambient air quality in Bangladesh: carbon monoxide, lead, nitrogen dioxide, particulate matter (PM), ozone (O₃), sulphur dioxide (SO₂), and ammonia (NH₃), which have a WHO standard 24-hour averaging concentration of 4 mg/m³, 0.15 µg/m³, 25 µg/m³, 15 µg/m³, 180 µg/m³, 40 µg/m³, and 200 µg/m³ respectively. Bangladesh experiences an annual mean PM2.5 exposure of 63 µg/m³, which is 12.6 times the WHO guideline of 5 µg/m³. This has had dire health consequences, with 74,000 deaths recorded in 2019 due to fine particulate matter, equivalent to 46 deaths per 100,000 people. Major causes of premature mortality from air pollution include chronic obstructive pulmonary disease (23%), lower respiratory infections (18%), and stroke (17%).

The main sources of air pollution include old brick kilns, unplanned urban expansion, unregulated industrial emissions, vehicular exhaust, and biomass burning. In particular, PM2.5 pollution is heavily influenced by vehicular emissions (36.5%), soil dust (42.9%), biomass burning (14.2%), and industrial activities (6.5%). Air quality monitoring between 2013 and 2018 showed that PM2.5 and PM10 levels consistently exceeded the Bangladesh Ambient Air Quality Standard (BAAQS) of 65 µg/m³ and 150 µg/m³, respectively, without significant improvement. In Dhaka, PM2.5 exceeded national standards on 72% of study days. During the same period, annual concentrations of SO₂, CO, NO₂ and O₃ remained within the BAAQS (The People’s Republic of Bangladesh, 2022). Monthly mean PM2.5 concentrations in Dhaka across multiple years show a distinct seasonal trend. PM2.5 levels peak during the winter months (November to February), often exceeding 100 µg/m³, and significantly decrease during the monsoon season (June to August), dropping below 50 µg/m³. Daily PM2.5 concentrations show high variability during winter, frequently spiking above 200 µg/m³, while summer months have lower, less fluctuating levels. 

The country has also seen a sharp rise in greenhouse gas (GHG) emissions. In 2012, total GHG emissions stood at 169.05 million tons of CO2 equivalent (MtCO₂e), with the energy sector contributing the most (55%), followed by the forestry and land-use sector (27.35%), waste (14.26%), and industrial processes (3.32%). Between 1990 and 2020, Bangladesh recorded a notable increase in nitrous oxide emissions, rising from 16.5 to 29.3 MT CO2.

Air pollution in Dhaka, analysed between 2013 – 2017 using ground observations, showed that almost all criteria pollutants exceeded the BAAQS, including PM2.5 (72 per cent of total study days), followed by PM10 (40 per cent of total study days), O₃ (1.7 per cent of total study days), SO₂ (0.38 per cent of total study days), and CO (0.25 per cent of total study days) (Rahman et al., 2019). Foy et al. (2021) continued to analyse the hourly fine particulate matter of PM2.5 from two monitoring sites in Dhaka (the U.S. monitoring site and the Darus-Salam site operated by the Ministry of the Environment), for dry months (November to March). The 24-hr averaged PM2.5 and PM10 concentrations from November to March solidified the trend that local ambient air quality was higher than WHO standards on 621 out of 685 days and 863 out of 914 days respectively. While there is a strong seasonal component to the concentration variability, the mean concentration of PM2.5 from November to March is around 140 to 150 µg/m³ at both sites, exceeding the standard of 65 µg/m³. Gaseous pollutants remain within the limits most of the days of the year (Bangladesh - Air Quality Management Project).

Yearly mean PM2.5 levels in major cities of Bangladesh show consistently high pollution, with Dinajpur and Bogra experiencing the highest concentrations, often exceeding 100 µg/m³. Dhaka and Sylhet exhibit moderate levels, fluctuating between 60-80 µg/m³, while Chittagong has the lowest values, remaining around 30-50 µg/m³. Trends indicate persistent air quality issues, with most cities far exceeding the WHO standard, highlighting severe pollution challenges across the country.

To combat air pollution, Bangladesh has taken significant policy measures, including banning leaded gasoline and two-stroke vehicles, promoting compressed natural gas (CNG) for transport, and implementing improved brick kiln technologies. The government has introduced electric vehicle policies (targeting 30% adoption by 2030), established a 100-day action plan, and drafted a National Air Quality Management Plan (NAQMP). Future efforts involve the use of satellite data for air quality monitoring, new continuous air monitoring stations, and an investment-backed National Clean Air Program supported by organizations like the World Bank and JICA. Despite these efforts, sustained policy enforcement and investment in cleaner technologies remain crucial for improving Bangladesh’s air quality.