You are here:
Modeling the effect of temperature on ozone-related mortality
Citation:
Wilson, A., A. Rappold, L. Neas, AND B. Reich. Modeling the effect of temperature on ozone-related mortality. Annals of Applied Statistics. Institute of Mathematical Statistics, Beachwood, OH, 8(3):1728-1749, (2014).
Impact/Purpose:
In this study we develop a model of evaluating joing effects of temperature and ozone on motality. The results of this study have important implication toward understanding the nature of the joint effects of ozone and temperature on mortality. To compare the ozone effect between different temperature strata it is im- portant that the distributions of ozone be similar within each strata. High correlation between temperature and ozone violate this requirement and thus call for careful consideration and interpretation of methods. Indeed, the results suggest that the higher ozone estimates at high temperatures in stratifed studies is primarily due to non-linear effect of ozone coupled with higher concentrations of ozone formed at high temperatures. However, the results also suggest that statistically signiffcant modiffication of risk is present at higher temperature levels.
Description:
Climate change is expected to alter the distribution of ambient ozone levels and temperatures which, in turn, may impact public health. Much research has focused on the effect of short-term ozone exposure on mortality and mobility, but less is known about the joint effects of ozone and temperature. The extent of the health effects of changing ozone levels and temperatures will depend on whether these effects are additive or synergistic. In this paper we propose a spatial, semi-parametric surface model to estimate the joint ozone- temperature risk surfaces in 95 US urban areas. Our methodology restricts the ozone-temperature risk surfaces to be monotone in ozone and allows for both non-additive and non-linear effects of ozone and temperature. We use data from the National Mortality and Morbidity Air Pollution Study (NMMAPS) and show that the proposed model fits `the data better than additive linear and non-linear models. We then examine the synergistic effect of ozone and temperature both nationally and locally and find evidence of nonlinear ozone effect and an ozone-temperature interaction at higher temperatures and ozone concentrations.