Temperature Modifies the Effects of Particulate Matter on Non-Accidental Mortality: A Comparative Study of Beijing, China and Brisbane, Australia

The interactive effect between temperature and ambient particulate matter on mortality has attracted attention world-wide, but the results of studies investigating this interaction have been inconsistent. This comparative study aims to further clarify this important public health issue. The present study used two separate time-series analyses to explore whether the mean temperature modified the impact of ambient particulate matter of less than 10 m in diameter (PM10) on daily non-accidental mortality in Beijing, China (2005–2009) and Brisbane, Australia (2004–2007). A bivariate response model and a stratification parametric model were used. The results show statistically significant interactive effects between PM10 and temperature on non-accidental mortality at various time lags. PM10 had a greater adverse effect on non-accidental mortality from cardiovascular disease on high temperature days. The interactive term coefficients per interquartile range increase in PM10 concentration and in high temperature levels were 1.95% (0.08%, 3.83%) in Brisbane, Australia on the current day and 0.25% (0.05%, 0.45%) in Beijing, China 2 days before the current day. The implications of this result indicate that it is important to reduce the emission of air particles on high temperature days in both cities, especially in Brisbane, Australia.