A BSTRACT This systematic review aggregates data from 15 articles published between 2000 and 2025 in PubMed, Scopus, and Google Scholar to discuss environmental exposures for lung cancer risk among never-smokers in Nigeria. The main drivers are indoor radon (levels 5–50 Bq/m 3 , occasionally higher than Nigeria’s 11.1 Bq/m 3 threshold in mining populations but within World Health Organization (WHO) 100 Bq/m 3 , associated with higher lung cancer risk by alpha radiation-induced DNA damage); particulate matter (PM 2.5 at 15–40 μg/m 3 in urban settings like Lagos and Port Harcourt, with hazard ratios 1.12–1.24 for lung cancer mortality per 10 μg/m 3 increase through inflammation and oxidative stress); household air pollution from biomass combustion (responsible for 10%–15% of never-smoker cases in rural settings, driven by carcinogens like polycyclic aromatic hydrocarbons); and asbestos (predominantly occupational in construction and mining but with rare environmental evidence but established causation of chronic inflammation leading to carcinogenesis). These exposures combined account for 15%–30% of lung cancer in Nigerian never-smokers. Although concentrations are predominantly below WHO guideline levels (100 Bq/m 3 for radon, 25 μg/m 3 for PM 2.5 ), localized exceedance and synergies with other factors underscore the need for stepped-up monitoring, cleaner energy transition, and public policy to diminish Nigeria’s industrial and rural lung cancer burden.
Oluwasegun et al. (Thu,) studied this question.