Old vehicle-emitted air pollution in Dhaka: A major driver of respiratory diseases

The persistent air pollution in Dhaka, Bangladesh, primarily arising from vehicular emissions of nitrogen dioxide (NO2), particulate matter (PM), carbon monoxide, and hydrocarbons, poses a significant public health crisis, significantly contributing to the prevalence of various respiratory diseases [1]. This alarming situation is exacerbated by rapid urbanization, inadequate infrastructure, and a high concentration of older, less-regulated vehicles, leading to consistently elevated levels of particulate matter [1]. These fine particulate matter pollutants (PM2.5 and PM10) are specifically linked to widespread respiratory diseases, cardiovascular complications, and elevated mortality rates within the population [2]. Specifically, approximately 85% of air pollution in Dhaka originates from brick kilns, surface dust, and vehicle emissions, with artificial sources broadly contributing more [3]. Therefore, this study aimed to report that old vehicle-emitted air pollution in Dhaka is the potential cause of respiratory disease.

Dhaka consistently ranks among the world’s most polluted cities, with PM2.5 and PM10 levels far exceeding national and WHO guidelines [1, 3-9]. The number of vehicles is increasing very quickly, a lot of which are old, refurbished, and not properly maintained. This has caused an uneven rise in emissions of carbon monoxide, nitrogen oxides, particulate matter, and other harmful pollutants [1, 4, 5, 10-12]. Diesel-powered buses, trucks, and two-stroke engine vehicles are particularly significant contributors, emitting high levels of black smoke and toxic gases [1, 4, 5, 11].

There are severe impacts of vehicle-emitted pollutants on health. Particularly, among vulnerable groups such as children, the elderly, and outdoor workers, exposure to vehicle-emitted pollutants is strongly linked to increased rates of respiratory diseases, including asthma, chronic bronchitis, reduced lung function, and pneumonia [3, 7, 8, 10, 12-15]. According to studies, prolonged exposure to vehicular air pollution in Dhaka is directly linked to alarmingly high rates of respiratory symptoms and impaired lung function in the traffic police and other high-exposure groups [10, 12-14]. Children are particularly at high risk, with elevated PM2.5 levels correlating with increased incidence of pneumonia and other respiratory diseases [8, 15]. The number of deaths in Bangladesh is increasing with increasing air pollution due to chronic respiratory diseases, according to GBD data of 2023 (Figure 1).

Figure 1. The number of deaths in Bangladesh is increasing with A) air pollution and B) chronic respiratory diseases in both sexes and all ages, according to Global Burden of Disease (GBD) 2023 data.

The economic burden of transportation-related air pollution is significant, encompassing healthcare costs, lost productivity, and a lower standard of living [[4]]. Some regulatory progress has been made in the fight against pollution, such as banning leaded gasoline and two-stroke engines. But the enforcement remains inconsistent, and the growing vehicle fleet threatens to outpace these gains [[1], [4], [5]].

A multi-pronged approach is required to mitigate this crisis of old vehicle-emitted air pollution in Dhaka. The approach includes making emission standards stricter, getting old cars off the road, encouraging the use of cleaner fuels and public transport, and adding more green spaces [1, 3, 5, 11]. To protect residents of Dhaka from the escalating health risks posed by vehicular air pollution, public awareness campaigns, frequent health monitoring for high-risk populations, and effective urban planning are crucial.

Without proper action to reduce emissions from older vehicles, Dhaka’s air pollution will continue to promote a growing epidemic of respiratory diseases, undermining public health and economic development (Table 1). The evidence is clear that cleaner transport and stronger regulation are urgent imperatives to hinder a growing epidemic of respiratory diseases in Dhaka.

None.

MJU and AM: Writing and original draft preparation; MAH and MJU: Writing-review and editing. All authors have read and agreed to the published version of the manuscript.

There is no conflict of interest among the authors.

During the preparation of this manuscript, the authors used artificial intelligence (AI) tools (such as Consensus and Quillbot) to improve readability and language quality. The author(s) reviewed and edited the text as required and take full responsibility for the text of the publication.