Phoenix Regional Heat and Air Quality Knowledge Repository

Objectives: We estimated neighborhood effects of population characteristics and built and natural environments on deaths due to heat exposure in Maricopa County, Arizona (2000–2008).

Methods: We used 2000 U.S. Census data and remotely sensed vegetation and land surface temperature to construct indicators of neighborhood vulnerability and a geographic information system to map vulnerability and residential addresses of persons who died from heat exposure in 2,081 census block groups. Binary logistic regression and spatial analysis were used to associate deaths with neighborhoods.

Results: Neighborhood scores on three factors—socioeconomic vulnerability, elderly/isolation, and unvegetated area—varied widely throughout the study area. The preferred model (based on fit and parsimony) for predicting the odds of one or more deaths from heat exposure within a census block group included the first two factors and surface temperature in residential neighborhoods, holding population size constant. Spatial analysis identified clusters of neighborhoods with the highest heat vulnerability scores. A large proportion of deaths occurred among people, including homeless persons, who lived in the inner cores of the largest cities and along an industrial corridor.

Conclusions: Place-based indicators of vulnerability complement analyses of person-level heat risk factors. Surface temperature might be used in Maricopa County to identify the most heat-vulnerable neighborhoods, but more attention to the socioecological complexities of climate adaptation is needed.

In this study we characterized the relationship between temperature and mortality in central Arizona desert cities that have an extremely hot climate. Relationships between daily maximum apparent temperature (ATmax) and mortality for eight condition-specific causes and all-cause deaths were modeled for all residents and separately for males and females ages <65 and ≥65 during the months May–October for years 2000–2008. The most robust relationship was between ATmax on day of death and mortality from direct exposure to high environmental heat. For this condition-specific cause of death, the heat thresholds in all gender and age groups (ATmax = 90–97 °F; 32.2‒36.1 °C) were below local median seasonal temperatures in the study period (ATmax = 99.5 °F; 37.5 °C). Heat threshold was defined as ATmax at which the mortality ratio begins an exponential upward trend. Thresholds were identified in younger and older females for cardiac disease/stroke mortality (ATmax = 106 and 108 °F; 41.1 and 42.2 °C) with a one-day lag. Thresholds were also identified for mortality from respiratory diseases in older people (ATmax = 109 °F; 42.8 °C) and for all-cause mortality in females (ATmax = 107 °F; 41.7 °C) and males <65 years (ATmax = 102 °F; 38.9 °C). Heat-related mortality in a region that has already made some adaptations to predictable periods of extremely high temperatures suggests that more extensive and targeted heat-adaptation plans for climate change are needed in cities worldwide.

Mortality from environmental heat is a significant public health problem in Maricopa County, especially because it is largely preventable. Maricopa County has conducted heat surveillance since 2006. Each year, the enhanced heat surveillance season usually begins in May and ends in October. The main goals of heat surveillance are to identify the demographic characteristics of heat-associated deaths (e.g., age and gender) and the risk factors for mortality (e.g., homelessness). Sharing this information helps community stakeholders to design interventions in an effort to prevent heat-associated deaths among vulnerable populations.

The two main sources of data for heat surveillance are: preliminary reports of death (PRODs) from the Office of the Medical Examiner (OME) and death certificates from the MCDPH Office of Vital Registration.

Heat-associated deaths are classified as heat-caused or heat related. Heat-caused deaths are those in which environmental heat was directly involved in the sequence of conditions causing deaths. Heat-related deaths are those in which environmental heat contributed to the deaths but was not in the sequence of conditions causing these deaths. For more information on how heat-associated deaths are classified, see the definitions in Appendix. For more information on MCDPH’s surveillance system, see Background and Methodology.

Maricopa County experiences extreme heat, which has adverse effects on community health and has been recognized as a serious public health issue. Therefore, the Maricopa County Department of Public Health (MCDPH) has conducted surveillance activities to assess morbidity and mortality due to extreme heat for the past 10 years. In 2016, MCDPH was interested in expanding their scope to include other climate-sensitive public health hazards. Subsequently, a network of stakeholders with an interest in the health effects of climate-sensitive hazards was established as the Bridging Climate Change and Public Health (BCCPH) stakeholder group. A smaller Strategic Planning Workgroup of key stakeholders from the BCCPH group was then convened over three sessions to work on a strategic plan for the group, which culminated in this document.

Practical Vision
The driving discussion question to identify the Strategic Planning Workgroup’s practical vision was, “What do we want to see in place in the next 3-5 years as a result of our actions?” The goal of this question was to help the group develop concrete outcomes that the BCCPH workgroup would like to achieve through activities included in the strategic plan. The following goals were identified:
 A healthy community infrastructure design
 Reframed messaging for multiple stakeholder needs
 A coordinated multi-scale education effort
 Improved health strategies and outcomes
 A diverse network of partnerships for climate change adaptation and mitigation planning and development
 New funding opportunities
 Policy and research strategies, and private sector engagement.

Underlying Contradictions
The driving discussion question to identify underlying contradictions was, “What is blocking us from moving towards our practical vision?” The following challenges were identified:
 People act out of self-interest vs. common good
 Siloed effects lead to poor coordination
 Political partisanship delays unified action
 Conflicting information leads to biases
 Culture and convenience impacts action
 Vulnerable populations not represented, and normalization of climate change related negative effects

Strategic Directions
During the BCCPH Strategic Planning Workgroup meetings, participants identified five strategic directions for addressing environmental concerns affecting the health and well-being of the community. These strategic directions are in agreement with the climate and health adaptation strategies outlined in the Arizona Climate and Health Adaptation Plan. The strategic directions for Maricopa County are:
 Fostering Environmental Action for a Healthier Community
 Coordinating Research and Collaborative Efforts to Catalyze Change
 Developing a Strategic and Targeted Communication Plan
 Promoting Community Awareness and Public Education about Climate and Health
 Celebrating Success and Champions