ScM Research Thesis

Social disparities in exposure to heat in Atlanta using CDC Environmental Public Health Tracking Network and NASA- ECOSTRESS satellite data

Introduction

As global warming and climate change have become increasingly prevalent phenomena, the intensity and frequency of extreme heat events has also seen an upward trend. Heat from these high temperatures represents a natural hazard that adversely affects human health. Accounting to approximately 650 deaths per year in the United States, extreme heat events cause more fatalities than any other weather hazard.

The purpose of my study is to; firstly, identify patterns of land surface temperature across Atlanta and secondly, to determine an association between exposure to heat and social determinants of health.


Background

Heat Stress Illness

In extreme heat conditions, internal body heat rises as a result of overwhelmed homeostatic mechanisms and causes heat stress illness.

The number of people affected and the inequity in how the community perceives these effects makes heat stress illness a public health concern.

Social determinants of health

The conditions in the environments in which people are born, live, learn, work and age can be known as the social determinants of health.

These determinants cause health disparities and inequities; and also play a vital role in the disparity in effects of heat exposure on populations.

CDC’s Environmental Public Health Tracking Network

CDC's Environmental Public Health Tracking Program is a multidisciplinary collaboration that involves the “ongoing collection, integration, analysis, interpretation, and dissemination of data from environmental hazard monitoring, human exposure surveillance, and health effects surveillance”.

The primary goal of the Tracking Network is to allow the exploration of data on health effects, environments, and demographics.

NASA-ECOSTRESS satellite

The ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) instrument was installed onboard the International Space Station (ISS) on June 29 th , 2018.

The ECOSTRESS mission provides both land surface temperature (LST) and emissivity at a spatial resolution of ~70 m × 70 m. This study filtered data scenes, using only cloud-free LST raster data evaluate heat patterns.

Legacy of segregation in Atlanta Metropolitan Area

Atlanta is the most segregated city in the South and the second-most segregated in the country. With a population that is 54% black and 38% white, it has a citywide diversity index of 56.8%. But its neighbourhood diversity index is just 30.7% reflecting historically redlined neighborhoods.


Research Questions and Aims

Aim 1

Explore the high resolution ECOSTRESS heat data to identify patterns across Fulton and DeKalb counties

Aim 2

Conduct exploratory data analysis to look for an association between exposure to heat and the social determinants of health in Atlanta


Research Strategy

Approach

  • Study population
  • Independent variable
  • Dependent variable
  • Statistical model

Results- Descriptive analysis

Day and night

Results- Descriptive analysis

Racial distribution

Results-Descriptive analysis

Income

Results-Descriptive analysis

Level of educational attainment

Results- Descriptive analysis

Specific findings

QTS Atlanta data center

Georgia World Congress Center

Georgia World Congress Center (2)

Peachtree-Dekalb airport

Peachtree-Dekalb airport (2)

Census tract with highest %asian

Results- Statistical analysis

Model 1: Race & LST

Results-Statistical Analysis

Model 2: Income & LST

Results-Statistical Analysis

Model 3: Educational attainment & LST


Conclusion

This study set out to look for an association between land surface temperatures and the social determinants of health or SDHs (racial distribution, median household income, level of educational attainment).

  • Although statistically significant association was found between LST and racial distribution for %Black, Hispanic and Asian, the values were small. Asian and Hispanic neighborhoods were more likely to see hotter temperature
  • Significant association between LST and median household income with a decrease of 1.2 °C per during day and decrease of 0.25 °C during night per 100,000 dollars increase in income
  • Significant increase in LST of 0.04°C with unit increase in %LessThanHighSchool level

Based on the results, evidence-based policy changes could better target limited resources to protect vulnerable populations from undue exposure to heat, thereby reducing number of illnesses, hospitalizations, and death due to extreme heat exposure.

The research can be used as a reproducible model in other cities for which ECOSTRESS data is available. It can be incorporated as an additional tool in the Environmental Public Health Tracking Network. Lastly, it can also help prepare   communities, first responders, and health workers for extreme heat exposure.

Primary Reader and Advisor: Dr. Megan Latshaw

Secondary Reader: Dr. Benjamin Zaitchik

CDC guide: Dr. Nicholas Skaff