Intersection of Air Pollution, Meteorological Factors, and the COVID-19 Pandemic: Sensitivity and Accountability
Date of Award
Spring 2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Public Health
First Advisor
Chen, Kai
Abstract
The coronavirus disease 2019 (COVID-19) pandemic has deeply impacted every aspect of the world, causing substantial health burden, societal disruption, and even environmental changes. In response to the challenges posed by COVID-19, this dissertation explores the complex interplay between air pollution, meteorological factors, and the COVID-19 pandemic, focusing on three critical questions that delve into the relationships among the environment, societal responses to the pandemic, and human health outcomes.The first project investigates the role of meteorological factors in the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) across 2,669 U.S. counties from March 15 to December 31, 2020. Utilizing daily mean temperature, specific humidity, and ultraviolet radiation data, along with estimated reproduction numbers, the research quantifies how these factors contribute to SARS-CoV-2 transmissibility. The findings indicate that cold and dry weather and low levels of ultraviolet radiation are moderately associated with increased SARS-CoV-2 transmissibility, with humidity playing the largest role. The second project examines the effects of COVID-19 lockdowns on ambient air pollution and subsequent mortality impacts in Jiangsu, China; California, U.S.; Central-southern Italy; and Germany. Employing a machine learning-based meteorological normalization technique and causal modeling, this project found that COVID-19 lockdowns in early 2020 overall improved air quality and brought attributable health benefits in areas mildly impacted by the pandemic, especially associated with nitrogen dioxide (NO2) improvements, with notable heterogeneity across regions. The lockdown-induced air quality improvement and health benefits were temporary and unsustainable; in contrast, long-term emission control policies, such as those enacted in the U.S., have successfully reduced air pollution levels over the past decades. Therefore, the third project estimates the benefits of long-term reductions in PM2.5 concentrations to cardiovascular health in the U.S., specifically for each racial/ethnic group. Using data from 2001 to 2016, this project estimates the association between PM2.5 exposure and cardiovascular disease mortality rates and assesses the PM2.5-attributable cardiovascular mortality burden by race/ethnicity. It reveals that despite overall improvements in air quality, non-Hispanic Black people still experience disproportionately higher PM2.5-attributable cardiovascular mortality, underscoring persistent racial/ethnic disparities. This dissertation explores questions ranging from the sensitivity of SARS-CoV-2 to meteorological conditions (sensitivity) to the effect of COVID-19 lockdowns on air pollution and human health (accountability) to the effectiveness and equity of environmental policies on air pollution and human health (accountability). Synthesizing all the findings, this dissertation highlights the role of cold and dry weather and low levels of ultraviolet radiation in SARS-CoV-2 transmission, the meaningful reductions in NO2 and associated mortality reductions during the COVID-19 lockdowns, and the substantial but inequitable cardiovascular mortality benefits brought by the long-term air pollution control policies in the U.S. These findings provide a foundational knowledge base for public policies and scientific research in the post-COVID-19 world.
Recommended Citation
Ma, Yiqun, "Intersection of Air Pollution, Meteorological Factors, and the COVID-19 Pandemic: Sensitivity and Accountability" (2024). Yale Graduate School of Arts and Sciences Dissertations. 1275.
https://elischolar.library.yale.edu/gsas_dissertations/1275
