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

The pervasive issue of air pollution in Dhaka, Bangladesh, particularly stemming from vehicular emissions, poses a significant public health crisis, contributing substantially to the prevalence of 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), specifically, are linked to widespread respiratory diseases, cardiovascular complications, and elevated mortality rates within the population 2. Specifically, approximately 85% of Dhaka's air pollution originates from brick kilns, surface dust, and vehicle emissions, with artificial sources broadly contributing more 3. Figure 1. Table 1.

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 rapid increase in vehicle numbers—many of which are old, reconditioned, and lack proper maintenance—has led to a disproportionate rise in emissions of particulate matter, nitrogen oxides, carbon monoxide, 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].

The health consequences are dire. Exposure to vehicle-emitted pollutants is strongly linked to increased rates of respiratory diseases, including asthma, chronic bronchitis, reduced lung function, and pneumonia, especially among vulnerable groups such as children, the elderly, and outdoor workers [3, 7, 8, 10, 12-15]. Studies of traffic police and other high-exposure groups in Dhaka reveal alarmingly high rates of respiratory symptoms and impaired lung function, directly associated with prolonged exposure to vehicular air pollution [10, 12-14]. Children are particularly at risk, with elevated PM2.5 levels correlating with increased incidence of pneumonia and other respiratory infections [8, 15]. According to GBD data of 2023, the number of deaths in Bangladesh due to chronic respiratory diseases is increasing with increasing air pollution (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-driven air pollution is substantial, encompassing healthcare costs, lost productivity, and reduced quality of life [4, 17]. While some regulatory progress has been made—such as banning leaded gasoline and two-stroke engines—enforcement remains inconsistent, and the growing vehicle fleet threatens to outpace these gains 1, 2, 4, 5.

Mitigating this crisis requires a multi-pronged approach: stricter emission standards, phasing out old vehicles, promoting cleaner fuels and public transport, and expanding green spaces [1-5, 12, 17]. Public awareness, regular health monitoring for high-risk groups, and robust urban planning are essential to protect Dhaka’s residents from the escalating health risks posed by vehicular air pollution.

Mitigating this crisis requires a multi-pronged approach: stricter emission standards, phasing out old vehicles, promoting cleaner fuels and public transport, and expanding green spaces [1-5, 12, 17]. Public awareness, regular health monitoring for high-risk groups, and robust urban planning are essential to protect Dhaka’s residents from the escalating health risks posed by vehicular air pollution.

Table 1: Key Findings on vehicle-emitted air pollution and respiratory health in Dhaka

Without decisive action to curb emissions from older vehicles, Dhaka’s air pollution will continue to fuel a growing epidemic of respiratory diseases, undermining public health and economic development. The evidence is clear: cleaner transport and stronger regulation are urgent imperatives for the city’s future.

None.

Conceptualization and design of the study, MJU; Writing and Original draft preparation, MJU and AM; Writing-Review and Editing, AM and MJU; Referencing, MJU; All authors have read and agreed to the published version of the manuscript.

There is no conflict of interest among the authors.