The Human Health Impacts of Short-Term Exposure to Climate Change-Influenced Environmental Hazards

Climate change poses a considerable threat to human health. Increases in temperatures and changes in weather patterns are likely to increase population-level exposure to many environmental hazards. While these hazards are associated with several adverse health outcomes, much is still unknown about the detrimental effects of climate change-influenced environmental exposures. To further elucidate the impacts of climate change on human health, this dissertation focused on short-term exposure to three key climate change-related hazards: wildfire smoke, fine particulate matter (PM2.5), and extreme heat. This work employed environmental exposure assessments, health impact assessments, and environmental epidemiologic approaches, using large-scale exposure and health datasets across the United States, to address unanswered questions. Specifically: (1) What is the acute health burden of exposure to wildfire PM2.5 and how can we best estimate these impacts? (2) Does exposure to PM2.5 and wildfire smoke negatively affect cognitive performance in adults, and if so, who is most affected? (3) Which urban populations are most vulnerable to the cardiovascular impacts of extreme heat exposure and do urban heat islands (UHIs) play an important role? The results show that: (1) Wildfire PM2.5 accounts for many excess respiratory and cardiovascular hospitalizations, especially in highly exposed and vulnerable communities, but these estimates are sensitive to the exposure and health risk estimates used; (2) Wildfire smoke and PM2.5 are associated with reduced attention in adults within hours and days of exposure, particularly in wildfire-impacted regions and among males and younger and older adults; and (3) Extreme heat increases the risk and burden of cardiovascular hospitalization in older urban populations, with significant city-to-city variation, and UHIs exacerbate these impacts among those with existing vulnerabilities. Taken together, these findings demonstrate that wildfire smoke, PM2.5, and extreme heat exposure pose substantial threats to respiratory, cardiovascular, and neurological health and disproportionately affect certain demographic and geographic groups. They also reveal the importance of using information-dense datasets to quantify the human health impacts of climate change-influenced environmental exposures. This research can provide guidance for investigating the climate change-health nexus moving forward and may have important implications when planning and preparing for increasingly frequent wildfires and heat waves.