The effects of dust-haze on mortality are modified by seasons and individual characteristics in Guangzhou, China

This study aimed to investigate the effects of dust-haze on mortality and to estimate the seasonal and individual-specific modification effects in Guangzhou, China. Mortality, air pollution and meteorological data were collected for 2006-2011. A dust-haze day was defined as daily visibility <10 km with relative humidity <90%. This definition was further divided into light (8-10 km), medium (5-8 km) and heavy dust-haze (<5 km). A distributed lag linear model (DLM) was employed. Light, medium and heavy dust-haze days were associated with increased mortality of 3.4%, 6.8% and 10.4% respectively, at a lag of 0-6 days. This effect was more pronounced during the cold season, for cardiovascular mortality (CVD), respiratory mortality (RESP), in males and people ≥60years. These effects became insignificant after adjustment for PM₁₀. We concluded that dust-haze significantly increased mortality risk in Guangzhou, China, and this effect appears to be dominated by particulate mass and modified by season and individual-specific factors.