Dhaka's unyielding air pollution

As one of the largest and most disaster-prone populous deltas in the world, Bangladesh is beset by over 10 million climate refugees, with an estimated 2,000 people moving to Dhaka every day. The infrastructurally underdeveloped megacity, already groaning under the weight of rural migration, is struggling to accommodate its overwhelming population density of 49,000 per square kilometer. This is evident in the water we drink, the soil that grows our food, and the air we breathe in.

Air pollutants such as particulate matter (PM 2.5 and PM 10), carbon monoxide (CO), ozone (O3), oxides of nitrogen (NOX), and sulfur dioxide (SO2) are chipping away at the physical and mental well-being of Dhaka's residents. The Air Quality Index (AQI) is measured on the basis of these key pollutants. The AQI informs the general public on the status of the air quality in a particular area and the required precautions for sensitive groups. Of the six hazardous air pollutants, PM 2.5, or Fine Particulate Matter is the most harmful. PM 2.5 is made of airborne particles measuring less than 2.5 micrometers in aerodynamic diameter. Due to its microscopic size, PM 2.5 is capable of penetrating deep into the lungs and entering the bloodstream. From there, it can reach the heart, brain, and other vital organs. Air pollutants can even pass through the placenta to adversely affect the development of a fetus. Pollution causes inflammation in the lungs and other body parts, with prolonged exposure linked to infectious diseases such as tuberculosis and pneumonia, as well as cataracts. PM 2.5 exposure in Bangladesh has increased by 12% from 2010 to 2019, with 31,300 deaths attributable to PM 2.5 concentrations over the last decade.

According to the Energy Policy Institute at the University of Chicago (EPIC), after cardiovascular disease, particulate pollution is the second greatest threat to human health in terms of life expectancy in Bangladesh. EPIC research confirms air pollution is cutting the life expectancy per person in Dhaka by about 8 years. In comparison, tobacco use reduces average life expectancy by 2.1 years, while child and maternal malnutrition reduces average life expectancy by 1.4 years.

The pathway to clear air begins with awareness. For the first time in Bangladesh, Shakti Foundation, one of the nation's largest non-government organizations, has pioneered an air pollution awareness campaign that visually demonstrates the impact of ambient air on healthy lungs. The campaign featured a 10-foot by 6-foot billboard retrofitted with artificial lungs made of metal frames, steel mesh, and cotton fabric filters. A motor-driven lever attached to the lungs simulated breathing while the filter fabric trapped air pollutants. For public health safety messaging, real-time AQI from the US Embassy Dhaka air quality sensors was displayed on the billboard along with the WHO Permissible AQI. A day ticker was also included to showcase the pollution effects within the activity timeframe. As more air pollutants were captured by the filter, the fabric on the lungs changed color from chalk white to muddy brown to inky black.

The first round of this campaign was launched on October 31, 2023, in Mirpur-11, Dhaka. This campaign coincided with several blockades preceding the national election. Yet, despite citywide vehicular restrictions, the lungs turned black within a span of just 21 days. On average, the AQI during this time period was 158 ?g/m³, roughly 3 times above the permissible WHO level of 50 ?g/m³. The results have been a brutal eye opener and generated quite a buzz among the masses.

The second and final round commenced on December 26, 2023, in the same locality. This time, the billboard was illustrated in Bangla for a wider reach. The peak winter season saw an upsurge of air pollutants, with AQI rising to a whopping 292 ?g/m³ on average, or 5.84 times the permissible level. This can be attributed to increased emissions as well as weather conditions that prevent pollution dispersion. As a result, the white lungs darkened within an alarming two weeks.

The scope of this special campaign is twofold: to build awareness and catalyze policy action. Approximately, 15,000 residents viewed the Clean Air installation in Mirpur on a daily basis, driving awareness and consideration on a mass level. To raise citywide awareness, Shakti Foundation's next step was to collaborate with local schools and prominent events like the Dhaka Flow Festival 2023 and Paara Utshob 2024. In each setting, over two thousand visitors were educated and sensitized on community-level pollutants, such as wood and fuel burning, garbage burning, and private vehicle emissions, as well as local, personal, and feasible actions that can be undertaken to mitigate air pollution. This includes eliminating neighborhood waste and/or leaf burning, planting and nurturing trees to sequester carbon emissions, reduce vehicle usage (carpool, bike, public transport, telecommute, electrical vehicles etc.) and monitoring AQI to make informed decisions related to daily activities (especially for children, elderly and those with comorbidities).

However, these measures are the least desirable choice in the hierarchy of interventions, with the most preferred being public policies aimed at reducing emissions. In this regard, the identification of pollutant sources and the extent of their contribution are imperative in the immediate term. A 2022 World Bank Report states that Dhaka's PM 2.5 is 150% above the WHO Air Quality Guidelines (AQG). The locations with major construction and persistent traffic have the highest level of air pollution. The second highest concentration of PM 2.5 levels is found near brick kilns in Greater Dhaka, which is 136% above the WHO AQG, the report added.

PM 2.5 speciation and source apportionment are critical as this key pollutant can originate from a wide range of sources and disseminate over several kilometers. This will involve transparency and engagement with source sectors such as transport, land-use, and urban planning, with a special emphasis on seasonal variation. Dhaka North City Corporation (DNCC), in partnership with Bloomberg Philanthropies, WHO, and Vital Strategies, has installed an entire network of low-cost sensors to improve its monitoring capacity. However, further collaboration on real-time air pollution measurements is required to guide effective emission control strategies.

Another timely measure is to regulate the validity of catalytic converters in automobiles. Catalytic converters control harmful pollution from exhaust fumes. They have an average lifespan of 10 years. Therefore, Bangladesh's Transport Policy should warrant a rigorous fitness check system where all cars, buses, and trucks older than a decade have to undergo and pass routine emissions testing to be eligible for road use.

Under the nation's legal framework, the Air Pollution Control Rules, 2022, was passed yearly this year. The Director General (DG) of the Department of Environment (DoE) has been empowered to deem highly polluted areas as "Degraded Air Shed" whereby non-compliance with the provisions of the Rules will invoke a fine of up to Tk 200 thousand and imprisonment of up to 2 years. The DG will also formulate a national air quality management system and award those who actively contribute to it. Building on this, Environment, Forest, and Climate Change Minister Saber Hossain Chowdhury has recently announced a lucrative incentive package to producers of non-fired concrete blocks in an impressive attempt to phase out the use of pollution generating clay bricks. He also intends to implement a Brick Kiln Tracker with National University of Singapore to detect pollutants from illegal brick kilns. This shift towards sustainable consumption is designed to lessen the damage to air quality and ecosystems. If implemented successfully, these interventions can create a culture of civic engagement that strengthens our environmental governance and sustains our communities.

The writer is Strategic Advisor, Climate Change Program, Shakti Foundation.

[email protected]