Public health impacts of climate change in Washington State: projected mortality risks due to heat events and air pollution

Abstract

C limate change is likely to have serious and long-term consequences for public health. Among these are illness and mortality related to heat and worsening air quality In this study we examined the historical relationship between age-and cause-specific mortality rates and heat events at the 99 th percentile of humidex values in the greater Seattle area (King, Pierce and Snohomish counties), Spokane County, the Tri-Cities (Benton and Franklin counties) and Yakima County from 1980 through 2006; the relative risk of mortality during heat events compared with more temperate periods were then applied to population and climate projections for Washington State to calculate number of deaths above the baseline expected to occur during projected heat events in 2025, 2045 and 2085. We also estimated excess deaths due to ground-level ozone concentrations for mid century (2045)(2046)(2047)(2048)(2049)(2050)(2051)(2052)(2053)(2054) in King and Spokane counties. Estimates were based on current (1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006) ozone measurements and mid-21 st century ozone projections, using estimates from the scientific literature to determine the effect of ozone on overall and cardiopulmonary mortality. For the historical heat analysis, relative risks derived for the greater Seattle area showed a significant dose-response relationship between duration of the heat event and the daily mortality rate for non-traumatic deaths for persons aged 45 and above, typically peaking at four days of exposure to humidex values above the 99 th percentile. Three different warming scenarios were considered, including high, low and moderate estimates. In the greater Seattle area, the largest number of excess deaths in all years and scenarios was predicted for persons aged 65 and above. Under the middle scenario, this age group is expected to have 96 excess deaths in 2025, 148 excess deaths in 2045 and 266 excess deaths in 2085 from all non-traumatic causes. Daily maximum 8 hour ozone concentrations are forecasted to be 16-28% higher in the mid 21 st century [1997][1998][1999][2000][2001][2002][2003][2004][2005][2006]. We estimated that the total non-traumatic ozone mortality rate by mid-century for King County would increase from baseline (0.026 per 100,000; 95% confidence interval 0.013-0.038) to 0.033 (0.017-0.049). For the same health outcome in Spokane County, the baseline period rate was 0.058 (0.030-0.085) and increased to 0.068 (0.035 -0.100) by mid-century. The cardiopulmonary death rate per 100,000 due to ozone was estimated to increase from 0.011 (0.005-0.017) to 0.015 (0.007-0.022) in King County, and from 0.027 (0.013-0.042) to 0.032 (0.015-0.049) in Spokane County. Public health interventions aimed at protecting Washington's population from excessive heat and increased ozone concentrations will become increasingly important for preventing deaths, especially among older adults. Furthermore, heat and air quality related illnesses that do not result in death, but are serious nevertheless, may be r...

Projections of mid-century summer air-quality for North America: effects of changes in climate and precursor emissions

“…This illustrates the importance of using a multi-pollutant health indicator such as the AQHI in order to determine the overall impact of emissions changes on mortality. Similar findings for the effect of future climate on air-quality-induced human health impacts have been found in other studies (increases in emergency department visits (Sheffield et al, 2011), mortality and premature death rates, Chang et al, 2010;Jackson et al, 2010;Selin et al, 2009). The timescale of impacts is worth considering in this regard: the effects of reductions of greenhouse gas emissions on climate change may require decades following enactment before a beneficial impact may be seen.…”

“…Makar et al, 2009) and ozone deposition (Engardt, 2008;Van Dingenen et al, 2009;Stella et al, 2011). The human-health impact of air pollution is one of the main drivers behind research in this field, with potentially substantial health effects resulting from climatechange-induced changes in air-quality (Sheffield et al, 2011;Chang et al, 2010;Tagaris et al, 2009Tagaris et al, , 2010Cheng et al, 2009;Jackson et al, 2010). Global financial losses due to reductions in crop yields resulting from ozone deposition are expected to reach between $1 billion to $17 billion, depending on the emissions scenario employed (Averny et al, 2011).…”

Regional climate model projections for the State of Washington

“…This issue is discussed in detail in Jackson et al (2010) where the quantitative relationship between heat events and mortality is analyzed, showing that mortality rises significantly after heat waves last for three or more days. Future heat wave frequencies are represented in Jackson et al (2010) by a uniform perturbation to the historic record since the global climate models do not give good information on the geographic signature of warming or changes in daily variability. Here we use output from the regional models to compute the frequency of heat waves for present and future time periods.…”

The geographic distribution and economic value of climate change-related ozone health impacts in the United States in 2030

“…Climate and air quality modeling are each time and resource intensive, so simulations focus on a limited number of projected years, climate scenarios, and geographic locations (Chang, Zhou, and Fuentes, 2010;Sheffield et al, 2011;Chang, Hao, and Sarnat, 2014;Jackson et al, 2010). Sheffield et al (2011) relate asthma emergency department visits in the 2020s in the New York City metropolitan area to simulated ozone changes using the IPCC A2 emission scenario.…”