The Impact of Oppressive Weather Conditions on Minority Mortality in Phoenix Adam J Kalkstein Department of Geography Arizona State University Laurence S Kalkstein Department of Geography University of Delaware
Nationwide Heat-Health Watch / Warning Systems • These systems are based on much more than just temperature and humidity • They are based on actual weather-health relationships, as determined by daily variations in human mortality
Minorities exhibit a late-season spike in summer mortality This is the only case where a portion of the population shows increased mortality late in the summer Unusual Results for Phoenix
Goals • To determine what is causing unusual heat-related mortality levels among minorities in Phoenix • To create an addition to the current Heat-Health system in Phoenix to warn when potentially dangerous weather conditions exist
Methods • This study will examine daily mortality, broken down by race, for the Phoenix Metropolitan Area from May 15 through September 30, 1975-1998. • The mortality data can then be compared to daily temperature, dew point, and air mass data throughout the summer season to better gauge what is causing the unusual late-season spike in minority mortality.
Data • Mortality data • Daily mortality levels for the Phoenix Metropolitan Area, broken down by race (white, black, Mexican Hispanic, non-Mexican Hispanic, other). • For this study, all non-whites are classified as minority
Data • Temperature data • Average daily temperature • Average daily dewpoint • Air mass data • DP, DM, DT, MP, MM, MT, TR • Since most summer days are either DT or MT, subsets of those air masses are created
Mortality Data Must be Standardized Average daily summer mortality levels in Phoenix (1975-1998)
Minorities exhibit a more pronounced dewpoint threshold, at around 13°C Thresholds for Increasing Mortality
First Clue? • The use of evaporative coolers in Phoenix is higher among minority communities. • Is it possible that the more humid conditions found later in the summer season cause these evaporative coolers to become ineffective, and thus, increase mortality?
Another Possibility… • If these excess deaths are within younger minority populations, this result might indicate that deaths are due to oppressive outdoor working conditions • We segregated population into elderly (over 65 years) and non-elderly populations
White Deaths and Dewpoint: MT+ Days • No response at all until dewpoints equal 21 degrees C or greater • Response is weak even above this dewpoint level; mortality increases about 10 percent among elderly, 8 percent above younger
Minority Deaths and Dewpoint: MT+ Days • Much greater negative health response within the non-white community • Elderly minority deaths begin to increase significantly at dewpoints equal or exceeding 20 degrees C • Increases in mortality top 50 percent in elderly minority population at dewpoints equal or exceeding 21 degrees C • Response in elderly population much greater than in younger population
White deaths and Dewpoint: DT+ Days • No response regardless of dewpoint
Minority Deaths and Dewpoint: DT+ Days • Responses within minority population exceed whites throughout range of dewpoints • Elderly response begins to increase significantly at dewpoints equal or exceeding 13 degrees C • Under 65 population shows little change in response through entire range of dewpoints • Note that DT+ days are hotter than MT+ days
What Does This Mean? • Since response is generally found within elderly minority population, we must assume that this is attributed to evaporative cooler inefficiencies rather than outdoor worker deaths • Whites show little response for both air masses regardless of dewpoint • Any other theories from the "audience"?
What Should We Do About This? • There is a need for an evaporative cooler alert system, to be issued by the Phoenix WFO • In our opinion, these alerts should be issued based on health outcome rather than discomfort • Most deaths above thresholds are not attributed to increased deaths among outdoor workers • We need a funding mechanism to develop these evaporative cooler warning systems. NOAA/NWS? Utilities? Local government?