Impact of climate change on ambient ozone level and mortality in southeastern United States

Abstract

There is a growing interest in quantifying the health impacts of climate change. This paper examines the risks of future ozone levels on non-accidental mortality across 19 urban communities in Southeastern United States. We present a modeling framework that integrates data from climate model outputs, historical meteorology and ozone observations, and a health surveillance database. We first modeled present-day relationships between observed maximum daily 8-hour average ozone concentrations and meteorology measured during the year 2000. Future ozone concentrations for the period 2041 to 2050 were then projected using calibrated climate model output data from the North American Regional Climate Change Assessment Program. Daily community-level mortality counts for the period 1987 to 2000 were obtained from the National Mortality, Morbidity and Air Pollution Study. Controlling for temperature, dew-point temperature, and seasonality, relative risks associated with short-term exposure to ambient ozone during the summer months were estimated using a multi-site time series design. We estimated an increase of 0.43 ppb (95% PI: 0.14-0.75) in average ozone concentration during the 2040's compared to 2000 due to climate change alone. This corresponds to a 0.01% increase in mortality rate and 45.2 (95% PI: 3.26-87.1) premature deaths in the study communities attributable to the increase in future ozone level.

Keywords: climate change; ground-level ozone; health impact.

Figure 1

A modeling framework integrating climate model outputs, meteorological observations, and health data to quantify the health impacts of future ozone level.

Figure 2

Locations of all NMMAPS communities (blue) used in the health model and the subset within the Southeastern U.S. study region (red).

Figure 3

Posterior mean and 95% posterior intervals of state-specific regression coefficients for the model of daily maximum 8-hour ozone concentration and meteorology variables in 2000.