Joint effects of temperature and humidity with PM2.5 on COPD

This case–control study examined the effects of environmental exposure to PM2.5, temperature, and relative humidity on the risk of COPD in patients with newly diagnosed COPD (n=995) and control subjects (n=833). At the time of entry into the study, all participants underwent lung function testing (FEV1, FVC, FEV1/FVC ratio), with data analyzed using Vitalograph Spirotrac V software.