The Impact of Oppressive Weather The Impact of Oppressive Weather Conditions on Minority Mortality in Conditions on Minority Mortality in

PhoenixPhoenix

Adam J KalksteinAdam J KalksteinDepartment of GeographyDepartment of GeographyArizona State UniversityArizona State University

Laurence S KalksteinLaurence S KalksteinDepartment of GeographyDepartment of Geography

University of DelawareUniversity of Delaware

Nationwide Heat-Health Watch / Nationwide Heat-Health Watch / Warning SystemsWarning 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

Unusual Results for PhoenixUnusual Results for Phoenix

• 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

Average Daily Mortality on Days with Average Temperatures > 36°C (1-day lag)

-0.02

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

June July August

Ave

rage

Mor

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dep

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re fr

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Minority

White

GoalsGoals

• 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

MethodsMethods

• 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.

DataData

• 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

DataData

• 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 Mortality Data Must be StandardizedStandardized

Average daily summer mortality levels in Phoenix (1975-1998)

Average Daily Mortality Within Average Daily Mortality Within Each Air MassEach Air Mass

Average Daily Mortality Within Each Air Mass

-0.2

-0.1

0

0.1

0.2

0.3

0.4

DP DT MP MT TR DT1 DT2 DT1/2 MT+

Ave

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Minority

White

Thresholds for Increasing MortalityThresholds for Increasing Mortality

Mortality On Days With Average Tempreratures Exceeding 37°C (1-day lag)

0

0.05

0.1

0.15

0.2

0.25

0.3

6 7 8 9 10 11 12 13 14 15 16 17

Average Dew Point

Ave

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fro

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Minority

White

• Minorities exhibit a more pronounced dewpoint threshold, at around 13°C

First Clue?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…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+ DaysWhite 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

White Deaths and Dewpoint: MT+ Days

-10

0

10

20

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60

10 11 12 13 14 15 16 17 18 19 20 21

Dewpoint

% C

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in M

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y

Under 65

Over 65

Minority Deaths and Dewpoint: MT+ DaysMinority 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

Minority Deaths and Dewpoint: MT+ Days

-10

0

10

20

30

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50

60

10 11 12 13 14 15 16 17 18 19 20 21

Dewpoint

% C

hang

e in

Mor

talit

y

Under 65

Over 65

White deaths and Dewpoint: DT+ DaysWhite deaths and Dewpoint: DT+ Days

• No response regardless of dewpoint

White Deaths and Dewpoint: DT+ Days

-10

0

10

20

30

40

50

60

5 6 7 8 9 10 11 12 13 14 15 16

Dewpoint

% C

hang

e in

Mor

talit

y

Under 65

Over 65

Minority Deaths and Dewpoint: DT+ DaysMinority 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

Minority Deaths and Dewpoint: DT+ Days

-10

0

10

20

30

40

50

60

5 6 7 8 9 10 11 12 13 14 15 16

Dewpoint

% C

han

ge

in M

ort

alit

y

Under 65

Over 65

What Does This Mean?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?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?