Dr Matiur Rahman & Shishir Reza :
Nine out of every 10 people in the world take in polluted air. Researchers mention older people with less formal education are at greater risk of air pollution because they are often involved in various activities outside the home.According to World Health Organization (WHO), around 8 million people die every year globally due to indoor and outdoor air pollution. Ninety-one percent of the world’s population lives in areas where air pollution levels are higher than those approved by the World Health Organization (WHO).
World Air Quality Report 2020 mentioned that South Asia remained the most polluted region of the world with Bangladesh, India and Pakistan sharing 42 of the 50 most polluted cities worldwide. The air quality of Bangladesh was the worst in the world, while its capital Dhaka was the second most air polluted city in 2020. The report also mentioned that an estimated 13-22 percent of deaths in this region are linked to the health effects of air pollution exposure, with associated estimated costs equating to 7.4 percent of the region’s GDP.
In 2020, Dhaka ranked as the second most polluted capital city globally. Its nearly 22 million residents were exposed to an annual average PM2.5 concentration of 77.1 µg/m3 polluted air, more than 7 times higher than the WHO annual mean for safer air at 10 µg/m3. Dhaka’s chronically polluted skies are a major public health concern. The WHO estimates that outdoor air pollution kills an estimated 108,000 Bangladesh residents every year, while countless others suffer morbidities associated with long-term exposure.
According to a report of IQAir during the first three months of 2021, Dhaka averaged a PM2.5 concentration of 154.6 µg/m3. Compared to the same period in years past, the start of 2021 was more polluted than the start of 2020 (141.8 µg/m3), 2019 (144.8 µg/m3), and 2017 (146.6 µg/m3), but less polluted than the start of 2018 (156.3 µg/m3).
The major causes of air pollution are the construction of unplanned buildings, roads and earth excavation for land development leads to air pollution. Increased demand for bricks is the outcome of an expanding construction industry, which follows rapid urbanization. To meet this demand, the number of brickfields keeps on increasing in the outskirts of urban areas. Brickfields are also responsible for air pollution in the area. These emit large amounts of smoke, fly ash, SO2 and dust which are carried by the wind in all directions. As these are situated conveniently near the cities, they pollute both the urban and the rural environment.
An Increase in urban population has created tremendous pressure on the existing network of intra-urban and inter-urban roads and highways as both the number and the volume of vehicular traffic increases within the city or in its outskirts at a specific time of the day, especially during rush hours. Apart from that, there is a question of registration and non-registration. Motorized vehicles are escalating day by day. Two-stroke three-wheelers, diesel-powered trucks, buses and defective motor vehicles of all types are responsible for the emission of NOx, SOx, CO, particulates and hydrocarbons.
Another contributing factor is the fuel being used by the automobiles spread – CO, CO2, NOx, SO2. The petroleum refinery of Bangladesh supplies diesel which contains 1% sulphur per litre although the international standard is 0.2%. The metal industries spread hydrogen sulphide, sulphur, fluorides, metal fumes( lead, zinc), smoke, particulates; power plants spread – fly ash, CO, sulphur and nitrogen oxides; trains spread – lead, smoke, hydrocarbons, aldehydes and peroxides.
Roadside digging by different agencies providing utility services seems to be taking place all year round and lacks coordination. When the sewerage lines are in place, the soil is removed and the road is repaired, a new set of digging is begun perhaps by the telephone company or the roads and highways authorities. There is no zoning in most of the urban areas. Industries are set up in residential areas with total disregard for the safety of the inhabitants of the area.
Air pollution is a major health concern nowadays. Among the diseases that can be caused by prolonged exposure to polluted air are heart disease; chronic lung disease including cough, pneumonia; lung infections; lung cancer; diabetes, various diseases caused by asthma and shortness of breath; stroke; cataracts in the eyes; problems of children and pregnant women, etc. Experts say that if one generation spends a long time in air pollution, it will have a devastating effect on the next generation.
Experts have suggested direct and indirect measures to undertake to reduce air pollution. The direct measures are dust control with water on the road or burning of garbage; planned mitigation of factories; moving those factories out of town; solving traffic jams; use advanced fuels; less use of air conditioner, etc. Indirect measures include extensive afforestation, as trees play a vital role in preventing air pollution; building houses and residential areas in a planned manner, where there will be gardens and ponds; construction work should be done in a controlled manner so that it does not cause pollution.
A rigorous monitoring system must be developed to detect faulty vehicles running on the roads and violators should be penalized. Emission from industries must be controlled using better, more efficient technology of emission control. Economic policies such as setting emission standards, emission charges and polluters to pay may be applied to reduce emission by industries. Brick kilns should use clean fuels and locate away from human settlements.
(Dr Matiur Rahman is Research Consultant, Human Development Research Centre and Shishir Reza is Environment Analyst, Associate Member, Bangladesh Economic Association).
