There is consistent evidence in the literature that the risk of death associated with short-term air pollution exposure is higher in elder populations than in younger populations. In addition to physiological changes that accompany age, older persons likely have different indoor/outdoor activity patterns, occupational exposures, and social networks. We found that particulate matter exposure risks were marginally higher for women than for men, which was consistent with a recent
systematic review and meta-analysis showing the weak evidence that women have higher risks of death from PM and some previous studies.