Climate Change, the Indoor Environment, and Health (2011) / Chapter Skim
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7 Thermal Stress
7 Thermal Stress
Pages 185-208
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From page 185... ...
. Associated with that temperature rise have been observations that heat waves have become longer and more extreme and that cold spells have become shorter and milder.
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From page 186... ...
, depending on the relative humidity. ASHRAE separately defines acceptable temperature ranges for naturally ventilated spaces as a function of outdoor temperatures spanning about 50–93°F (10–34°C)
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In areas of the country where hot and humid outdoor conditions become more common, air-conditioning units may run longer to restore or maintain comfortable indoor humidity. Potential increases in the magnitude and frequency of peak electricity demand due to heat waves and in the occurrence of extreme weather events have also led to concerns over power outages that could leave building occupants without sources of conditioned air.
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From page 188... ...
The largest effect was observed in the Northeast and Midwest US census regions, the smallest in the South, even though the longest heat waves occurred in that region. Analyses also found that heat waves at the beginning of the warm weather months had greater mortality effects (5.04%, nationally)
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That is based on both physiologic and social factors: decreased organ function, interactions between medications and heat-compensation mechanisms, overall poor health status, isolation, and decreased access to support services. There are stark physiologic differences between younger adult and elderly populations.
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Few studies have looked specifically at obese or overweight persons and heat waves, but some information is available. Obesity was a comorbidity in the 2003 European heat wave (Vandentorren et al., 2006)
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. Although there are few studies of cardiovascular disease and heat, some links have been found between increased mortality during heat waves and the presence of cardiovascular diseases (Hoffmann et al., 2008; Kenny et al.
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. In the 1995 Chicago heat wave, several trends due to social isolation were discovered.
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A heat island absorbs and stores heat during the day and radiates it during the night, sustaining higher temperatures and intensifying the effects of heat waves (Luber and McGeehin, 2009)
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Cooling degree days are calculated by subtracting a balance temperature from the mean daily temperature and summing only positive values over an entire year. Heating degree days are used to estimate how cold the climate is and how much energy may be needed to keep buildings warm.
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ment of Energy's Residential Energy Consumption Survey found that 33% of residences that had central air conditioning and 11% of residences that had window or wall units reported using an air conditioner "all summer" in 1981 (DOE, 2000)
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. The authors speculated that the increased indoor humidity caused by evaporative cooling might support fungi or dust mites and associated adverse exposures.
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suggested that "measures to improve indoor temperature control and increase ventilation rates will be highly cost effective, with benefit–cost ratios as high as 80 and annual economic benefits as high as $700 per person." Chapter 8 summarizes the epidemiologic literature on a related issue, the health and productivity effects of ventilation. EFFECTS OF COLD EXPOSURE As Chapter 2 notes, measurements of global mean temperature in recent years indicate that cold spells in the United States have become shorter and milder.
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From page 198... ...
However, two other chapters of this report address issues indirectly related to climate change, cold-weather conditions and health: Chapter 4 discusses adverse exposures associated with extreme weather events, including the use of unvented space heaters, back-up electrical power generators, and biofuel stoves indoors, and Chapter 6 talks about the influence of seasonality on the availability and spread of infectious agents. CLIMATE-CHANGE ADAPTATION AND MITIGATION MEASURES Protection from the adverse effects of heat exposure requires the ability to lower core temperature and often involves maintaining or moving to a temperate space.
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2007) and regionally and seasonally appropriate use of landscape elements and trees to block summer sunlight but permit winter solar heating have also been shown to reduce cooling and heating loads and peak energy demands (Akbari, 2002)
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(2007) note that such features are especially important in low-income housing, where residents are more likely to suffer from heat stress and poor indoor environmental quality.
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However, there is concern that peak energy demands during extreme heat events and an increased frequency of extreme weather events may result in more frequent power outages that ex pose large numbers of persons to potentially dangerous conditions indoors.
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2009. Weather-related mortality: How heat, cold, and heat waves affect mortality in the United States.
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1998. Near-fatal heat stroke during the 1995 heat wave in Chicago.
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2001. The impact of heat waves and cold spells on mortality rates in the Dutch population.
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2010. The health impacts of heat waves in five regions of New South Wales, Australia: A case-only analysis.
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2002. Heat-related mortality during a 1999 heat wave in Chicago.
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1999. Excess hospital admissions during the July 1995 heat wave in Chicago.
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1994. Seasonal variations of plasma fibrinogen and factor VII activity in the elderly: Winter infections and death from cardiovascular disease.
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