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Air pollution is a pervasive environmental issue with profound implications for public health. It is composed of various pollutants, including particulate matter (PM), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), ozone (O₃), and volatile organic compounds (VOCs). These pollutants originate from multiple sources such as industrial emissions, vehicular exhaust, agricultural activities, and residential heating. Over the past few decades, numerous studies have established a strong link between air pollution and various health problems, including respiratory diseases, cardiovascular conditions, and adverse pregnancy outcomes. Increasingly, air pollution is also being recognized as a significant risk factor for cancer [1].

Cancer epidemiology involves studying the distribution and determinants of cancer incidence and mortality across different populations. Understanding the role of air pollution in cancer epidemiology is crucial for developing effective public health strategies and policies aimed at reducing the global cancer burden. This article explores the impact of air pollution on cancer epidemiology from a global perspective, discussing the mechanisms by which pollutants contribute to cancer development, the types of cancers most strongly associated with air pollution, and the geographical and socioeconomic disparities in exposure and outcomes [2].

Description

Mechanisms of air pollution-induced carcinogenesis

The carcinogenic potential of air pollution is mediated through several biological mechanisms. Fine particulate matter (PM2.5 and PM10) can penetrate deep into the respiratory system and even enter the bloodstream, causing inflammation, oxidative stress, and DNA damage [3]. These particles often carry adsorbed toxic substances, including polycyclic aromatic hydrocarbons (PAHs), heavy metals, and persistent organic pollutants (POPs), which can directly damage cellular components and induce mutations.

Gaseous pollutants such as NO2 and SO2 can irritate the respiratory tract and facilitate the entry of other carcinogens into the lungs. Ozone, a powerful oxidant, can damage epithelial cells and impair the lung’s defense mechanisms, increasing susceptibility to carcinogens. VOCs, including benzene and formaldehyde, are known to be potent carcinogens that can cause mutations and disrupt cellular processes.

Types of cancer associated with air pollution

Air pollution is most strongly associated with lung cancer, given the direct exposure of the respiratory system to airborne pollutants. Epidemiological studies have consistently shown that long-term exposure to elevated levels of PM2.5 and NO2 is linked to increased lung cancer incidence and mortality. The International Agency for Research on Cancer (IARC) has classified outdoor air pollution and particulate matter as Group 1 carcinogens, indicating sufficient evidence of their carcinogenicity in humans [4].

Beyond lung cancer, emerging evidence suggests that air pollution may also contribute to other types of cancer. For instance, studies have indicated associations between air pollution and bladder cancer, possibly due to the systemic effects of inhaled pollutants and their subsequent excretion through the urinary system. There is also growing concern about the potential links between air pollution and breast cancer, although the evidence is less conclusive and warrants further investigation.

Geographical and socioeconomic disparities

The impact of air pollution on cancer epidemiology is not uniform across the globe. Low- and middle-income countries (LMICs) often experience higher levels of air pollution due to rapid industrialization, urbanization, and less stringent environmental regulations. As a result, populations in these regions face a greater risk of pollution-related cancers. For example, countries like India and China have some of the highest levels of air pollution and corresponding high rates of lung cancer [5].

Socioeconomic disparities also play a critical role in determining exposure to air pollution and cancer risk. Vulnerable populations, including those with lower income, limited access to healthcare, and residing in highly polluted areas, are disproportionately affected [6,7]. Environmental justice issues arise when marginalized communities bear the brunt of pollution-related health impacts, necessitating targeted interventions to reduce these inequities.

Conclusion

Air pollution is a significant environmental determinant of cancer, with a clear link to lung cancer and emerging evidence for other cancer types. The global burden of air pollution-related cancer highlights the need for comprehensive public health strategies to reduce exposure to harmful pollutants. This requires coordinated efforts at international, national, and local levels, including stricter emission regulations, promotion of clean energy sources, and public awareness campaigns.

Addressing the geographical and socioeconomic disparities in air pollution exposure and cancer outcomes is crucial for achieving health equity. Policymakers must prioritize actions that protect the most vulnerable populations and ensure access to clean air as a fundamental human right. Continued research is essential to further elucidate the mechanisms of air pollution-induced carcinogenesis and to inform evidence-based interventions aimed at reducing the global cancer burden attributable to air pollution.

Acknowledgement

None

Conflict of Interest

None

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