Air pollution is a critical environmental and public health challenge worldwide, exerting considerable detrimental consequences on human health and well-being. The World Health Organization (WHO) estimates that outdoor air pollution causes around 4.2 million premature deaths globally each year, disproportionately affecting vulnerable and marginalized people. (WHO, 2024). Air pollution, consisting of fine particulate matter (PM2.5), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and ground-level ozone (O₃), is a primary contributor to respiratory and cardiovascular disorders, especially in heavily populated urban regions. The effects are exacerbated in low-income and marginalized groups that frequently encounter elevated exposure levels and insufficient healthcare resources to address pollution-related health consequences (WHO, 2024). 

The Indian subcontinent faces severe and escalating issues from air pollution, exacerbated by growing industrialization, urbanization, and motorization. India, Pakistan, and Nepal consistently record among the highest PM2.5 concentrations globally, attributed to urban development, traffic emissions, construction dust, and industrial operations. (Greenstone M. et al., 2015). In urban parts of this region, underprivileged people experience heightened exposure to air pollution due to their proximity to pollution hotspots, including industrial zones and high-traffic areas, coupled with inadequate housing and limited access to healthcare facilities. (Chowdhury et al., 2007). Research indicates that these neighborhoods endure an inequitable prevalence of respiratory and cardiovascular disorders due to prolonged exposure to substandard air quality, highlighting a troubling environmental imbalance in urban health outcomes. (Maheshwar Dwivedy, 2013).

In Bangladesh, the circumstances are especially dire in prominent urban areas like Dhaka, Chittagong, and Khulna, where air pollution levels often surpass the permissible thresholds established by both the WHO and national regulations.(Faisal Ahmed et al., 2024). Dhaka ranks as one of the most polluted cities worldwide, with high PM2.5 and PM10 concentrations mostly due to automobile emissions, brick kilns, construction, and industrial operations. (Begum & Hopke, 2018). The marginalized urban people in Bangladesh are particularly susceptible, frequently residing in densely populated regions with inadequate infrastructure and near pollution sources. This proximity intensifies their health risks, as seen by the elevated incidence of respiratory disorders, cardiovascular diseases, and other health conditions associated with pollution in these communities (Rahman & Alam, 2021). The health effects of air pollution on marginalized people are a significant worry due to the countrys fast urbanization and continuous industry. In Bangla-desh, more than 63% of the population lives in metropolitan areas, where industrial emissions, automobile exhaust, building activities, and biomass combustion significantly contribute to heightened pollution levels. (WHO, 2024). 

Marginalized people, such as low-income communities, slum inhabitants, and informal sector laborers, are especially susceptible due to their restricted access to healthcare, financial limitations, and frequently inadequate living conditions (Begum & Hopke, 2018). Moreover, marginalized communities typically inhabit low-income, densely populated regions, where their closeness to industrial sites and main transport corridors markedly heightens their exposure to toxic chemicals. A major element contributing to the vulnerability of marginalized communities in metropolitan Bangladesh is socioeconomic inequality, which influences living conditions, health status, and resilience to environmental hazards (Najmun Nahar et al., 2022). Marginalized groups, particularly individuals in low-income brackets and ethnic minorities, frequently lack the resources to move to less polluted regions, so rendering them vulnerable to the detrimental environmental conditions in their vicinity. Furthermore, inadequate policy execution and deficient urban planning intensify these problems. The Bangladeshi government has implemented measures to mitigate industrial emissions and vehicular pollution: however, enforcement is patchy, especially in economically deprived regions (Hossain et al., 2021; Peimani M., and Kalantari A., 2024).

The absence of research investigating the interplay between socio-economic determinants and insufficient healthcare access exacerbates health risks, creating a substantial void in comprehending the comprehensive scope of environmental injustice and public health issues affecting underprivileged urban residents in Bangladesh. The objective of this work is to provide a thorough examination of air pollution sources in metropolitan regions of Bangladesh, emphasizing the spatial distribution of these contaminants within underprivileged groups. This study aims to investigate the health effects of air pollution exposure on these populations, focusing specifically on respiratory, cardiovascular, and other pollution-related disorders. This research will examine socio-economic and demographic factors that increase vulnerability, focusing on the inequalities in air quality and exposure levels between marginalized and non-marginalized groups. The study seeks to assess the efficacy of environmental policies and regulatory frameworks in reducing pollution and safeguarding underprivileged urban people in Bangladesh. Addressing the impact of air pollution on vulnerable communities is crucial for ensuring fair health outcomes and enhancing the quality of life in urban Bangladesh. This review seeks to consolidate current research on air pollution and health inequalities, emphasizing the role of socio-economic determinants in intensifying the health impacts of pollution exposure among underprivileged urban communities. This study analyzes the intersections of environmental pollution, socio-economic vulnerability, and health outcomes to inform targeted policy interventions and identify opportunities for future research in urban health and environmental management in Bangladesh. The research conducted by addressing some research questions based on objectives, like, a) What are the primary sources of air pollution in urban areas of Bangladesh, and how are they spatially distributed within marginalized communities? b) How does exposure to air pollution affect the health of marginalized populations in urban Bangladesh, particularly concerning respiratory, cardiovascular, and other pollution-related diseases? c) What socio-economic and demographic factors contribute to the increased vulnerability of marginalized groups to air pollution in urban Bangladeshi settings? d) What disparities exist in air quality and exposure levels between marginalized and non-marginalized communities in Bangladeshs urban areas? e) How effective are current environmental policies and regulatory frameworks in reducing air pollution exposure and protecting marginalized populations in urban Bangladesh?

This study used a qualitative research design that analyses secondary data to investigate the complex interplay between air pollution, health outcomes, and socio-economic issues impacting marginalized communities in metropolitan Bangladesh. This methodology entailed a comprehensive examination of academic databases, including PubMed, JSTOR, Google Scholar, and pertinent national research portals, concentrating on papers published during the past 10 to 15 years. Targeted search phrases, such as "air pollution and health," "marginalized communities," and "urban Bangladesh," were employed to locate peer-reviewed literature, governmental reports, and statistics that pertain to the principal concerns of air quality and health inequities in this setting. 

The research utilized a descriptive and analytical approach, relying on existing academic literature, governmental papers, NGO publications, media articles, and historical documents as primary data sources. Data analysis has revealed repeating patterns and themes pertinent to the objectives. The content analysis was employed to evaluate current policies in Bangladesh concerning air pollution and public health, highlighting deficiencies in implementation that disproportionately impact underprivileged people. Content analysis facilitates a methodical examination of repeating patterns and topics within textual material (Krippendorff, 2018).

Inclusion criteria

Criteria for inclusion in the study. Incorporated according to defined criteria to guarantee the relevance and quality of the research. The geographical focus is on metropolitan areas of Bangladesh, which is crucial for comprehending the situation of marginalized communities inside the nation. The evaluation exclusively encompassed research that primarily focus on marginalized or low-income urban populations. Only peer-reviewed studies, official reports, and pertinent NGO publications will be evaluated, ensuring that the review accurately reflects current facts and trends. Furthermore, works utilizing quantitative, qualitative, or mixed-method approaches were deemed appropriate for inclusion.

Table 1: Research Design and Methodological Framework. 

This table effectively summarizes the key elements of the research methodology, allowing readers to understand the approach and focus of the study at a glance.

Exclusion criteria

Exclusion criteria were implemented to eliminate irrelevant studies. Research conducted outside metropolitan regions of Bangladesh was eliminated to concentrate on the distinct issues encountered by marginalized communities in urban environments. Furthermore, research that fails to specifically investigate marginalized or low-income areas or those that concentrate on general populations without differentiating socio-economic status, will be eliminated. Publications over 15 years have been excluded to guarantee that the evaluation includes the most current evidence and advancements in the field. Ultimately, studies deficient in methodological rigor, including those missing clear definitions, sufficient sample numbers, or suitable statistical analyses, were removed from the review. The evaluation seeks to provide a targeted and pertinent analysis of the impact of air pollution exposure on the health of underprivileged communities in metropolitan Bangladesh by implementing these inclusion and exclusion criteria. 

This study aims to conduct a complete investigation of air pollution sources in metropolitan regions of Bangladesh, emphasizing the geographical distribution of these contaminants within underprivileged groups. This study aims to investigate the health effects of air pollution exposure on these populations, focusing specifically on respiratory, cardiovascular, and other pollution-related disorders. The research will examine socio-economic and demographic factors that increase vulnerability, focusing on inequalities in air quality and exposure levels between marginalized and non-marginalized groups. The study seeks to assess the efficacy of environmental policies and regulatory frameworks in reducing pollution and safeguarding under-privileged urban people in Bangladesh. The principal sources of air pollution in metropolitan regions of Bangladesh and their spatial distribution, especially concerning underprivileged communities. Certain studies have identified sources of contamination. Refer to Table 1 for a description of the source and its particular effects on vulnerable populations. Industrial emissions from factories and manufacturing facilities are a significant source of air pollution, especially in urban areas.

Air pollution in Bangladesh urban areas and its spatial distribution in marginalized communities

Table 2: Sources of Air Pollution in Urban Areas of Bangladesh and Their Spatial Distribution in Marginalized Communities. 

As Dhaka and Chittagong, where disadvantaged groups frequently live near these industrial operations. Research demonstrates that these emissions markedly elevate exposure to detrimental pollutants, such as particulate matter (PM) and volatile organic compounds (VOCs), leading to increased health hazards. Brick kilns, typically located in peri-urban regions, represent a significant source of air pollution. These kilns emit significant quantities of particulate matter, associated with respiratory ailments and other health concerns affecting nearby underprivileged communities (Nargis et al., 2022). Moreover, the dependence on conventional brick-making techniques, combined with inadequate regulatory supervision, intensifies this issue, resulting in heightened pollution levels in areas unable to evacuate. Vehicular emissions pose an additional difficulty, as urban slums are frequently situated along heavily trafficked roadways populated by older, more polluting vehicles. Studies indicate that these emissions result in elevated levels of nitrogen oxides (NOx) and carbon monoxide (CO), hence exacerbating air quality issues in these areas (Hasan et al., 2022).

The influence of residential sources, especially the combustion of solid fuels for cooking and heating, is considerable, as it exacerbates indoor air pollution that disproportionately impacts low-income households. Construction activities in metropolitan regions produce dust and pollutants, exacerbating particulate matter exposure in communities already afflicted by pollution from other sources. The aggregate impact of these diverse pollution sources underscores the pressing necessity for specific measures to alleviate air pollution and safeguard the health of underprivileged communities in metropolitan Bangladesh. The chart highlights the intricate relationship between socioeconomic determinants and environmental health, emphasizing the need for effective policy interventions to mitigate these inequities. Investigating the sources of pollution between global and Bangladesh is not significantly different as shown in Fig. 1.

Fig. 1: Comparison Source of Pollution Between Global and Bangladesh (Source: Author, 2024).

The health impacts of air pollution exposure on marginalized populations

The health effects of air pollution on marginalized groups in metropolitan Bangladesh are significant, with exposure predominantly associated with respiratory, cardiovascular, and other pollution-related illnesses. Research demonstrates that marginalized communities experience increased exposure to pollutants such as PM2.5, Sulphur dioxide (SO₂), nitrogen dioxide (NO₂), and carbon monoxide (CO), which substantially contribute to health problems due to their proximity to pollution sources, including industrial areas, major thoroughfares, and regions with high vehicular density. These communities often encounter heightened PM2.5 levels, leading to an increased incidence of respiratory disorders, including asthma and chronic obstructive pulmonary disease (COPD) (Khandker et al., 2022). However, the principal health effects of air pollution on underprivileged communities in metropolitan Bangladesh, are categorized by specific diseases and associated contaminants. In the initial category, respiratory diseases, pollutants including PM2.5, Sulphur dioxide (SO₂), and nitrogen dioxide (NO₂) significantly exacerbate illnesses such as asthma, chronic obstructive pulmonary disease (COPD), and various lung infections. Research demonstrates that children, the elderly, and low-income individuals residing in pollution-dense regions, such as those adjacent to factories or main thoroughfares, face a heightened risk of respiratory issues (Khuda, 2020).

Table 3: Health Impacts of Air Pollution on Marginalized Populations in Urban Bangladesh. 

The second group, cardiovascular diseases, emphasizes pollutants such as NO₂, SO₂, and carbon monoxide (CO), which are associated with heightened occurrences of hypertension, myocardial infarctions, and cerebrovascular accidents. These pollutants elicit inflammatory reactions in the body, resulting in oxidative stress and harming the cardiovascular system. This is particularly apparent in adults and the elderly within marginalized communities who are more prone to living in regions with elevated vehicle and industrial pollutants (Nargis et al., 2022). The third group, Other Pollution-Related Diseases, pertains to exposure to volatile organic compounds (VOCs) and heavy metals, which impair immune responses and heighten vulnerability to infections. However, vulnerable populations encompass children and pregnant women, who face heightened risks of negative pregnancy outcomes, including preterm birth and low birth weight, in places with elevated pollution levels. Moreover, the elderly encounter heightened risks owing to the synergistic impact of age-associated immunological deterioration and extended exposure to these poisons (Hossain et al., 2021). This table (see Table 2) highlights the varied health risks faced by marginalized communities due to air pollution exposure, emphasizing the need for policy interventions to mitigate these impacts and improve environmental health equity in urban Bangladesh.

Socio-economic and demographic factors contributing to higher vulnerability to air pollution among marginalized groups in urban Bangladesh

In metropolitan regions of Bangladesh, socio-economic and demographic factors considerably exacerbate the susceptibility of underprivileged populations to air pollution exposure. Studies demonstrate that these populations frequently reside in regions with elevated pollution levels, attributable to industrial operations, heavy traffic, and insufficient natural spaces (Clougherty, 2010). Socio-economic limitations, like inadequate income and restricted housing availability, compel numerous underprivileged groups to live near pollution sources, hence heightening their susceptibility to pollution-related health problems. Socio-economic and demographic factors that exacerbate the susceptibility of marginalized urban people in Bangladesh to air pollution, along with the effects of each aspect. The Income Level element is crucial as low-income families sometimes reside in affordable yet highly polluted regions adjacent to industrial zones and major thoroughfares. These settings heighten exposure to contaminants, but constrained financial resources limit access to healthcare and the feasibility of relocation to cleaner environments (Islam, 2022). Educational attainment contributes to susceptibility, as those with lesser education frequently lack awareness of the health concerns linked to pollution and are employed in high-risk occupations within industries such as manufacturing and construction, where exposure levels are heightened. This deficiency in understanding preventive measures exacerbates their vulnerability (Khan et al., 2023a). Educational attainment contributes to susceptibility, as those with lesser education frequently lack awareness of the health concerns linked to pollution and are employed in high-risk occupations within industries such as manufacturing and construction, where exposure levels are heightened. This deficiency in understanding preventive measures exacerbates their vulnerability (Namdeo et al., 2011). The Household Size factor relates to the prevalence of larger families in low-income communities, who often live in overcrowded conditions with poor ventilation. Solid fuels are commonly used for cooking due to economic limitations, leading to increased indoor pollution, which further heightens health risks (Hossain et al., 2021). Finally, gender roles significantly influence exposure levels, since women in low-income homes frequently assume cooking responsibilities, hence increasing their exposure to elevated indoor air pollution from solid fuels. Cultural barriers may restrict womens access to healthcare, exacerbating their pollution-related health effects (Rahman & Alam, 2021). Following the Table 3.

Table 4: Socio-Economic and Demographic Factors Contributing to Higher Vulnerability to Air Pollution Among Marginalized Groups in Urban Bangladesh. 

Disparities in air quality and exposure levels between marginalized and non-marginalized communities

The differences in air quality and exposure levels between disadvantaged and non-marginalized populations in metropolitan Bangladesh highlight substantial discrepancies in environmental health risks. Research indicates that marginalized communities, frequently situated near industrial areas, major thoroughfares, and informal waste disposal sites, experience significantly greater exposure to pollutants such as particulate matter (PM2.5), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and volatile organic compounds (VOCs) than affluent, non-marginalized neighborhoods  (Shahrukh et al., 2023). The discrepancies mostly arise from the spatial distribution of residential zones, as marginalized people generally reside in lower-cost housing situated in locations with elevated pollution levels. Studies show that the average concentration of PM2.5 in disadvantaged communities frequently surpasses the World Health Organizations (WHO) recommended thresholds, intensifying health hazards for inhabitants (Rahman & Alam, 2021). The discrepancies mostly arise from the spatial distribution of residential zones, as marginalized people generally reside in lower-cost housing situated in locations with elevated pollution  levels. Studies show that the average concentration of PM2.5 in disadvantaged communities frequently surpasses the World Health Organizations (WHO) recommended thresholds, intensifying health hazards for inhabitants (Hossain et al., 2021).

Data on NO₂ concentrations also underscore variations in air quality among different populations. In marginalized regions, NO₂ concentrations are typically elevated due to traffic pollution and insufficient green spaces that may otherwise mitigate pollutants. A study in Dhaka revealed that NO₂ concentrations in lower-income regions were twice as high as those in rich areas, highlighting the correlation between socioeconomic status and exposure to traffic-related pollution (Moore et al., 1997). SO₂ exposure significantly differs among communities, with marginalized populations disproportionately affected by emissions from adjacent industrial operations. This pollutant, predominantly released by industrial facilities and power generation plants, poses a considerable danger for respiratory illnesses. Marginalized communities adjacent to pollution sources frequently exhibit SO₂ levels that exceed health-based guidelines established by national authorities, highlighting the disparity in exposure (Hossain et al., 2021). Furthermore, inequalities in exposure to volatile organic compounds (VOCs), encompassing various chemicals emitted from industrial activities and waste, are significant among these groups. Inhabitants of marginalized communities frequently report exposure to these substances, resulting in increased risks of respiratory and other pollution-related health problems (Fahmida Khatun & Kashfia Ashraf, 2021). In contrast, non-marginalized communities, typically removed from industrial operations, encounter reduced levels of VOC exposure. The data indicate that marginalized groups in urban Bangladesh experience significantly higher levels of air pollution exposure than non-marginalized communities. The disparity is exacerbated by socio -economic status, residential location, and restricted access to resources, highlighting the necessity for policy interventions to tackle environmental inequality and guarantee equitable access to cleaner air in all metropolitan populations in Bangladesh. 

The Role of Environmental Policies and Regulatory Frameworks in Mitigating Air Pollution

To acquire knowledge the examination of environmental policies and regulatory frameworks in alleviating air pollution and safeguarding marginalized populations in urban Bangladesh concentrated on existing literature. Bangladesh has enacted environmental policies and regulatory frameworks aimed at reducing urban air pollution and its unequal effects on vulnerable communities. Principal strategies concentrate on diminishing emissions from industrial sectors and transportation, enhancing air quality surveillance, and establishing emission benchmarks. Nonetheless, the implementation of these policies frequently differs, leaving underprivileged communities susceptible due to insufficient local enforcement, poor resources, and various socioeconomic obstacles. Table 4 delineates key environmental policies and regulatory frameworks pertinent to air quality management in metropolitan regions of Bangladesh, as well as their efficacy in addressing underprivileged communities.

The table illustrates that The National Environment Policy, (1992) established the groundwork for environmental protection in Bangladesh, addressing general pollutants such as PM2.5, SO₂, and NO₂, while emphasizing sustainable development. Although it seeks to regulate air pollution in metropolitan regions, enforcement in vulnerable populations, particularly in informal settlements, is still inadequate. Research has shown enforcement difficulties stemming from insufficient resources and the necessity for tailored pollution control measures to safeguard communities from elevated exposure levels (Ahmed et al., 2022). The Air Quality Management Project (AQMP), established in the early 2000s, especially targets particle matter (PM2.5 and PM10). While air quality has improved in certain urban areas due to enhanced monitoring and data collecting, underprivileged neighborhoods continue to endure comparatively high levels of exposure.

Table 5: Indicates Policies and Regulatory Framework. 

The implementation of AQMP is robust in major urban centers such as Dhaka, while it is less effective in densely populated informal settlements, where pollutant concentrations frequently surpass permissible limits (Land, 2021).

The Brick Kiln Control Act, (2013) regulates emissions from brick kilns, a highly polluting sector in Bangladesh. Brick kilns substantially contribute to PM2.5 and CO emissions, adversely affecting air quality in adjacent underprivileged populations. Although enforcement has intensified around bigger, registered kilns, unregistered and smaller kilns in informal sectors circumvent the regulation, resulting in ongoing exposure hazards for lower-income communities adjacent to these kilns (Hossain et al., 2021) (Yamamoto et al., 2014).

Finally, the Environmental Conservation Act, (1995) serves as an overarching regulatory framework to limit pollutant emissions across industries, but its enforcement in marginalized areas is notably weak. While the act provides a legal basis for environmental protection, marginalized communities frequently lack adequate monitoring and enforcement, exposing them to unregulated pollution sources like informal industrial sites and waste-burning practices (Salamat Khandker, n.d.). Overall, while Bangladesh has a suite of environmental policies and frameworks designed to mitigate urban air pollution, their effectiveness in marginalized communities remains limited due to uneven enforcement, and infrastructure gaps. However, the Vehicle Emission Standards (2015) seek to mitigate vehicular emissions by imposing restrictions on pollutants such as NO₂ and CO, especially in densely populated urban regions with elevated traffic levels. Notwithstanding these rules, underprivileged areas frequently endure heightened levels of traffic-related pollution due to their proximity to busy thoroughfares. The exposure is exacerbated by inadequate enforcement infrastructure, which undermines the efficacy of emission restrictions in densely populated, low-income metropolitan areas, and socio-economic constraints. These findings underscore the need for targeted policy adjustments and enhanced enforcement mechanisms that specifically address the vulnerabilities of marginalized populations.