Pollution Free Cities: Risk of Dying from Heat Waves in US Cities

Wednesday, December 1, 2010

Risk of Dying from Heat Waves in US Cities

Heatwaves in the United States: Mortality Risk During Heatwaves and Effect Modification by Heatwave Characteristics in 43 US Communities (41 page pdf, Environ Health Perspect, November 18, 2010)

Also discussed here: Heat Waves, Climate Change and Urban Mortality (Pollution Free Cities, Jul. 30, 2010)

The article reviewed today reports on a comprehensive study of heat waves in the US and their impact on mortality, including, for the first time, an analysis of the differences that are seen between communities in their responses to heat. There is no mention of the additional effect of air pollution during the heat waves which might have made the analysis of mortality clearer as to the cause- heat or pollution (or both acting together)- as done in this study in southern Canada Differential and combined impacts of extreme temperatures and air pollution on human mortality in south–central Canada. Part II: future estimates and in this study Health Impacts of Urban Sprawl, combined with Pollution and Climate Warming

Key Quotes:

“we estimate the mortality effects of heatwaves across the United States (43 communities) for the period 1987-2005 and determine how these effects change when heatwaves are more intense, longer, or earlier in the summer”

“A 1oF increase in average Tmean during a heatwave was associated with a 4.39% increase in the relative risk of mortality during that heatwave in the Northeast and a 3.22% increase in the Midwest.”

“The association between heatwave duration and mortality effects was largest in the Northeast, where mortality risk during a heatwave was on average 2.50% higher for every extra day a heatwave lasted“

“within a community, heatwave mortality effects are influenced by the heatwave’s intensity, duration, and timing in the season. This effect modification probably results from physiological responses to heat and/or behavior modification”

“Power outages sometimes occur during heatwaves .. and these could contribute to particularly high impacts due to increased heat exposure without AC and greater difficulty leaving upper-level apartments in buildings with elevators”

“the observed heterogeneity, both in heatwave effects and in the influence of heatwave characteristics on mortality effects between different communities, indicates the importance of developing heatwave response plans that are community-specific"