Assessing the Cardiopulmonary Health Effects of Exposure to Multiple Ambient Pollutants and PM2.5 Speciation Restricted; Files Only

Abstract

Ambient air pollution remains a global public health concern due to its associations with various adverse health outcomes, including cardiovascular and respiratory diseases. Coronary heart disease (CHD) is the leading cause of death worldwide. In China, CHD prevalence has significantly increased alongside economic growth in recent decades. Previous studies have established a link between CHD and ambient PM2.5; however, PM2.5 consists of diverse chemical constituents, and evidence of their differential health effects remains inconsistent. Additionally, ozone (O3) has emerged as an important air pollutant, yet research into its long-term health effects remains limited.

This dissertation utilized data from the Prediction of ASCVD Risk in China (China-PAR) cohort, a nationwide, multicenter cardiovascular study, with advanced machine learning for exposure assessment. Aim 1 explored the long-term health effects of O3 on acute myocardial infarction (AMI) incidence and mortality. Results demonstrated that elevated warm-season O3 concentrations were associated with increased AMI incidence and mortality, with stronger effects observed at higher exposure levels. Potential additive and multiplicative interactions between O3 and PM2.5 were also identified, underscoring the importance of coordinated pollutant control strategies.

In Aim 2, using the China-PAR cohort and satellite-based PM2.5 constituent models, we evaluated differential health impacts of long-term exposure to specific PM2.5 constituents on CHD incidence and mortality. Organic carbon (OC) and nitrate were found to have stronger associations with CHD outcomes compared to elemental carbon (EC), while sulfate showed relatively weaker effects. These results suggest that targeted interventions focusing on specific PM2.5 constituents could yield significant public health benefits.

Finally, wildfire events substantially elevate PM2.5 concentrations, particularly in the western United States. In Aim 3, we analyzed over six million respiratory emergency department visits using advanced wildfire-specific PM2.5 modeling. Wildfire smoke PM2.5 is found associated with increasing respiratory emergency department visits, and such associations are stronger than PM2.5 from other sources. The effect of wildfire smoke PM2.5 is found linear, and no lag effect was found, suggesting immediate public health responses following wildfire events are crucial to mitigate these health impacts.

Table of Contents

1. INTRODUCTION

1.1 References:

2. AIM 1: LONG-TERM EFFECT OF OZONE EXPOSURE ON ACUTE MYOCARDIAL INFARCTION IN CHINESE ADULTS

2.1. Abstract

2.2. Introduction

2.3. Method

2.3.1. Study population

2.3.2. Outcome Definition

2.3.3. Exposure Assessment

2.3.4. Statistical analysis

2.4. Results

2.5. Discussion

2.6. Conclusion

2.7. Acknowledgement

2.8. Figures

2.9. References

3. AIM 2: LONG-TERM EXPOSURE TO PM2.5 CONSTITUENTS AND CORONARY HEART DISEASE INCIDENCE AND MORTALITY IN CHINA, EVIDENCE FROM A NATIONAL COHORT STUDY

3.1. Abstract

3.2. Introduction

3.3. Method

3.3.1. Design, Setting, and Study Population

3.3.2. Outcomes

3.3.3. Exposure Assessments

3.3.4. Statistical Analysis

3.4. Results

3.5. Discussions

3.6. Limitation

3.7. Figures

3.8. References

4. AIM 3: DIFFERENTIAL EFFECTS OF WILDFIRE SMOKE PM2.5 EXPOSURE ON RESPIRATORY DISEASE EMERGENCY DEPARTMENT VISITS IN THE WESTERN UNITED STATES

4.1. Abstract

4.2. Introduction

4.3. Method

4.3.1. Emergency department visits

4.3.2. Exposure assessment

4.3.3. Time-relevant Covariates

4.4.4.  Statistical analysis

4.4.5. Stratified Analysis

4.4.6. Sensitivity Analysis

4.5. Results

4.5.1. Study Population

4.5.2. Effects of wildfire smoke and non-smoke PM2.5

4.5.3. Stratified Analysis

4.5.4. Sensitivity Analysis

4.6. Discussions

4.7. Figures

4.8. Reference

5. CONCLUSIONS

6. APPENDIX A. SUPPLEMENTARY MATERIAL FOR AIM 1

7. APPENDIX B. SUPPLEMENTARY MATERIAL FOR AIM 2

8. APPENDIX C. SUPPLEMENTARY MATERIAL FOR AIM 3

About this Dissertation

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School	Laney Graduate School
Department	Environmental Health
Degree	Ph.D.
Submission	Dissertation
Language	English
Research Field	Health Sciences, Public Health Health Sciences, Epidemiology Environmental Health
Keyword	Coronary heart disease Wildfire Respiratory disease Air pollution Acute myocardial infarction
Committee Chair / Thesis Advisor	Yang Liu, Emory University
Committee Members	Howard H. Chang, Emory University Stefanie Ebelt, Emory University Joshua S. Fu, University of Tennessee, Knoxville Fengchao Liang, Southern University of Science and Technology Alvaro Alonso, Emory University

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