Assessing and Reducing Exposure to Heat Waves in Cuyahoga County, Ohio.

Abstract

In the United States, more people die from heat waves than from any other type of natural disaster. Climate change will increase the frequency and intensity of extreme heat events. Fatalities during hot weather occur primarily in cities, in part due to the urban heat island effect. This dissertation addresses heat-related exposure in Cuyahoga County, Ohio and is structured around three complementary studies. The first study investigates the urban heat island effect using a mobile measurement platform. Variations in solar radiation and albedo led to greater-than-30°C shifts in the ground surface temperature. Air temperatures recorded downwind from forested areas were 0.25°C cooler than those recorded over impervious, bare soil, or grass land covers. Water provided a cooling effect that was roughly 2.7 times stronger than that of a forest. However, large areas of forest or water were necessary to reduce the local air temperature; 11.8 hectares of water (29.16 acres) resulted in only a 0.67°C reduction in temperature. A second study addresses exposure in single family detached houses. Five house types were modeled in thermal load software with different configurations of insulation, air infiltration, and windows to evaluate the effect of weatherization on annual energy usage, air-conditioning operation, and indoor temperature. Weatherization lowered the yearly cost to heat and cool a house by $260 to $480 USD; it also decreased electricity usage associated with air-conditioning by more than 35%. Weatherization reduced the required size of air-conditioning equipment by 40 to 50% per house. However, if windows remain closed during warm weather, weatherization treatments may increase exposure to temperatures above the ASHRAE thermal comfort zone. A final study investigates how professionals responsible for reducing exposure to high temperatures define and act to reduce temperature-related morbidity and mortality. Using a system of professions approach, professionals from the health, building science, and urban environment policy sectors were linked to tasks they consider their jurisdiction, such as cooling centers, residential energy efficiency, or developing codes and standards. Results from twenty-eight semi-structured interviews indicate barriers among programs. Collaborative efforts may help to bridge among disciplines and improve strategies to reduce exposure to future heat waves.