Ambient Ozone, PM1 and Female Lung Cancer Incidence in 436 Chinese Counties.

Ozone air pollution has been increasingly severe and has become another major air pollutant in Chinese cities, while PM1 is more harmful to human health than coarser PMs. However, nationwide studies estimating the effects of ozone and PM1 are quite limited in China. This study aims to assess the spatial associations between ozone (and PM1) and the incidence rate of female lung cancer in 436 Chinese cancer registries (counties/districts). The effects of ozone and PM1 were estimated, respectively, using statistical models controlling for time, location and socioeconomic covariates. Then, three sensitivity analyses including the adjustments of smoking covariates and co-pollutant (SO2) and the estimates of ozone, PM1 and SO2 effects in the same model, were conducted to test the robustness of the effects of the two air pollutants. Further still, we investigated the modifying role of urban-rural division on the effects of ozone and PM1. According to the results, a 10 μg/m3 increase in ozone and PM1 was associated with a 4.57% (95% CI: 4.32%, 16.16%) and 4.89% (95% CI: 4.37%, 17.56%) increase in the incidence rate of female lung cancer relative to its mean, respectively. Such ozone and PM1 effects were still significant in three sensitivity analyses. Regarding the modifying role of urban-rural division, the effect of PM1 was greater by 2.98% (95% CI: 1.01%, 4.96%) in urban than in rural areas when PM1 changed by 10 μg/m3. However, there was no modification effect of urban-rural division for ozone. In conclusion, there were positive associations between ozone (and PM1) and the incidence rate of female lung cancer in China. Urban-rural division may modify the effect of PM1 on the incidence rate of female lung cancer, which is seldom reported. Continuous and further prevention and control measures should be developed to alleviate the situation of the two air pollutants.