Investigating the Association between Air Pollution and Cognitive and Mental Health Outcomes Using Satellite-Driven Exposure Models Open Access

Abstract

Air pollution has been linked to various adverse health outcomes, affecting cardiovascular, respiratory, reproductive, and renal systems. According to the Global Burden of Disease (GBD) study, air pollution was the fourth leading contributor to global attributable deaths for both males and females in 2019. Nevertheless, existing epidemiological studies typically focus on a specific type of air pollutant due to the limited availability of large-scale exposure matrices. Recent advances in satellite remote sensing have provided a promising tool to evaluate the long-term spatiotemporal distribution of air pollution in a large domain.

In this dissertation, we first established a high-performance O3 prediction model in China using the OMPROFOZ ozone profile. The model considered the two major pathways (i.e., the photochemical reactions between NOx and volatile organic compounds (VOCs) and the stratospheric intrusion) through which ground-level O3 pollution is produced. Our prediction model achieved a random CV R² of 0.87 at a high spatial resolution of 0.05°. The model predictions also agreed well with the TOAR historical ozone monitoring data from 2005-2013.

Combining our ozone model with other satellite-driven exposure datasets, aim 2 of this dissertation examined the association between long-term exposure to air pollution and cognitive impairment among the Chinese elderly population using data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). We found that annual average exposure to PM2.5 and NO2 were both associated with an increased risk of cognitive impairment. Although the annual average of daily maximum 8-hour average (MDA8) O3 was not positively associated with cognitive impairment, warm-season (April-September) mean MDA8 O3 was identified as a significant risk factor.

In addition to anthropogenic emissions, air pollution may also be produced by natural disasters, especially wildfires. Aim 3 of this dissertation evaluated the association between wildfire-related exposures and ED visits for anxiety disorders in the Western US using satellite-driven exposure data. Our results suggested that wildfires are associated with anxiety disorders through two different pathways, i.e., the inhalation of smoke PM2.5 and the direct psychological impact of smoke events and active fire points. Furthermore, women and the elderly population are more susceptible to the anxiety disorders associated with wildfires.

 

Table of Contents

1. Introduction. 1

1.1. References. 6

2. Satellite-based long-term spatiotemporal patterns of surface ozone concentrations in China: 2005-2019. 16

2.1. Abstract 16

2.2. Introduction. 18

2.3. Data and Methods 21

2.3.1. Model Development 21

2.3.2. Ground ozone measurements. 21

2.3.3. OMI data. 23

2.3.4. MERRA-2 assimilated data. 24

2.3.5. Lightning flash density. 24

2.3.6. South and Southeast Asia wildfire. 24

2.3.7. Land use, population, road length, and digital elevation. 25

2.3.8. Missing value imputation. 26

2.3.9. Data integration. 27

2.3.10. Model training, validation, and parameter comparison. 28

2.3.11. Coupled trend evaluation between ozone and PM2.5 29

2.4. Results. 30

2.4.1. Model performance and parameter comparison. 30

2.4.2. Predictor importance ranking. 32

2.4.3. Seasonality and spatial heterogeneity of ozone levels in China. 32

2.4.4. The long-term trend of ozone in China. 34

2.4.5. Couple trend between PM2.5 and ozone in China. 35

2.5. Discussion. 36

2.6. Conclusions 42

2.7. Acknowledgments. 42

2.8. References. 43

2.9. Figures. 49

3. Air pollution and cognitive impairment among the Chinese elderly population: A Nationwide cohort study 57

3.1. Abstract 57

3.2. Introduction. 59

3.3. Methods. 61

3.3.1. Study population. 61

3.3.2. Exposure assessment 62

3.3.3. Measurement of cognitive impairment 63

3.3.4. Covariates 63

3.3.5. Statistical analysis. 64

3.4. Results. 65

3.5. Discussion. 67

3.6. Conclusions 70

3.7. References. 71

3.8. Tables and Figures 75

4. The Association between Wildfire and Emergency Department (ED) Visits for Anxiety Disorders in the Western United States. 81

4.1. Abstract 81

4.2. Introduction. 83

4.3. Methods. 85

4.3.1. ED visits for anxiety disorders. 85

4.3.2. Exposure assessments. 86

4.3.3. Meteorological data. 87

4.3.4. Statistical analysis. 87

4.4. Results. 89

4.4.1. Study population. 89

4.4.2. The effects of wildfire smoke PM2.5 90

4.4.3. The effects of smoke events 91

4.4.4. The effects of active fire points and FRP. 91

4.5. Discussion. 92

4.6. Conclusions 95

4.7. References. 96

4.8. Tables and Figures 102

5. Conclusions 110

6. Appendix A. Supplemental materials for manuscript 1. 112

7. Appendix B. Supplemental materials for manuscript 3. 132

About this Dissertation

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School	Laney Graduate School
Department	Environmental Health
Degree	Ph.D.
Submission	Dissertation
Language	English
Research Field	Environmental Health
Keyword	Exposure science Remote sensing Air pollution
Committee Chair / Thesis Advisor	Yang Liu, Emory University
Committee Members	Stefanie Ebelt, Emory University Howard Chang, Emory University Kyle Steenland, Emory University

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