The joint impact of ambient air pollution and extreme temperatures on asthma-related emergency department visits in Kentucky

Author

Marissa E. English, University of KentuckyFollow

Date Available

5-1-2027

Year of Publication

2025

Document Type

Graduate Capstone Project

Degree Name

Master of Public Health (M.P.H.)

College

Public Health

Department/School/Program

Public Health

Faculty

Dr. Yisi Liu, PhD

Committee Member

Dr. Tianjun Lu, PhD

Faculty

Dr. Erin Haynes, DrPH, MS

Faculty

Dr. Anna Hoover, PhD

Abstract

Introduction

In the United States, the state of Kentucky ranks 5th for the highest prevalence of asthma for adults and the number of emergency department visits for asthma in Kentucky has increased from the previous year recorded. With extreme temperatures becoming more common, there are expected exacerbations of both asthma and allergic respiratory conditions due to increases in air pollutants, and inhalation of both extreme cold and extreme warm air.

Objective

The aim of this study is to examine the joint impact of air quality and extreme temperatures on rates of asthma-related emergency department (ED) visits in Kentucky counties via a cross-sectional study design using linear regression models.

Methods

Data for each Kentucky county annual average for air pollutant levels, asthma related ED visits, and weather measures were retrieved for the 2008-2019 time period. Correlation metrics and Bayesian Information Criterion (BIC) comparisons were used to select measurements to be included in the linear models. Using a categorical Wet Bulb Globe Temperature (WBGT) measure, levels of extreme warm, medium, and extreme cold were used to construct a stratified linear regression model.

Results

All pollutants were independently associated with asthma ED visits. SO₂ had a greater impact on asthma ED visits in extreme cold years than medium WBGT years [2.79] vs. [0.45]. PM_2.5 had a greater impact on asthma ED visits in extreme cold years than medium WBGT years [6.75] vs. [3.04]. O₃ had a greater impact on the asthma ED visits in extreme warm years than medium WBGT years [3.50] vs. [3.36]. SO₂ and PM_2.5’s associations in the extreme cold subset and O₃ and PM_2.5‘s associations in the extreme warm subset showed statistical significance at a 95% confidence interval.

Conclusion

During extreme cold years, per standard deviation increased in SO₂, asthma ED visit rate increased 2.79 per 10,000 population. In cold years as compared to medium WBGT years, per standard deviation increase in PM_2.5, asthma ED visit rate increased 6.75 per 10,000 population. Also in cold years, as compared to medium WBGT years, O₃ showed an asthma ED visit rate increase by 3.50 per 10,000 population per standard deviation increase. With the identification of these combined effects on asthma ED rates, especially in areas lacking health care resources, push-based health communication can be used to make vulnerable populations aware of increased risks

Recommended Citation

English, Marissa E., "The joint impact of ambient air pollution and extreme temperatures on asthma-related emergency department visits in Kentucky" (2025). Theses and Dissertations--Public Health (M.P.H. & Dr.P.H.). 474.
https://uknowledge.uky.edu/cph_etds/474