Objective  To explore the impact of long-term exposure to fine particulate matter (PM_2.5) on the incidence of lung cancer in Beijing residents in China.

Methods  Based on the data of meteorological data, PM_2.5 mass concentrations and the incidence of lung cancer, the exposure-response relationships among long-term exposure to PM_2.5 and the lung cancer population, adenocarcinoma population, and gender-specific and age-specific populations were established by the nonparametric generalized additive model, and the impact of long-term exposure to PM_2.5 on the incidence of lung cancer was assessed.

Results  The critical exposure time window was 3 years for the lung cancer population, adenocarcinoma population, females, and populations aged 30-64 and 65-74 years, and was 5 years for males and populations aged ≥ 75 years by the impact of PM_2.5. For the total population, the relative risks (RR_s) of lung cancer and adenocarcinoma incidence, were 1.23 (95% confidence intervalCI: 1.03-1.46) and 1.48 (95% CI: 1.05-2.08), respectively, with each 10 μg/m³ increase in the 3-year average PM_2.5 mass concentrations. For gender-specific populations, the RR of lung cancer incidence due to long-term exposure to PM_2.5 was greater in males than in females. For age-specific populations, the RR of lung cancer incidence due to long-term exposure to PM_2.5 was greater in populations aged ≥ 75 years. However, differences between different gender and age stratifications were not statistically significant (P>0.05).

Conclusion  Long-term exposure to PM_2.5 significantly increases the risk of lung cancer incidence in Beijing residents especially in males and the elderly (≥ 75 years).