Health and economic benefits of reducing air pollution exposure through adaptation and mitigation under a changing climate

Abstract

Air pollution is the world’s largest environmental health risk. Even in countries with perceived clean air, like the United States of America (U.S.) and Canada, ambient air pollution still contributes to approximately 150,000 and 17,500 annual premature mortalities, respectively.

Air pollution is expected to worsen under climate change, leading to increases in mean ozone and PM2.5 concentrations and higher extreme values. These changes could lead to more air quality alerts, which are triggered when Air Quality Index (AQI) values exceed certain thresholds. Though they are the main medium for communicating air pollution risk to the public, the effect of climate change on air quality alerts has not been previously studied.

The effectiveness of air quality alerts, and the adaptation behaviors they recommend, is also not well known. Few studies have investigated how people respond to air quality alerts, and none have looked at how behavioral responses may change in the future. Even fewer studies quantify the health benefits that adapters, or those who respond to air quality alerts, receive from their adaptation. This is critical to understand, as air pollution is a significant public health threat now and, without emission reductions, is expected to worsen this century.

The studies included in this dissertation use modeled future data to elucidate how air quality alerts driven by PM2.5 and ozone change throughout the 21st century. They identify who is affected by the increase in air quality alerts and model how these populations might respond. The use detailed time use, location, and building parameter data to provide improved estimates of adaptation behaviors.

Across the three studies, we find adaptation - including limiting time outdoors, masking, and reducing infiltration - to be useful in reducing ambient air pollution exposure. However, adaptation benefits are not distributed evenly across the population. Certain populations, like seniors (aged 65+), receive much higher benefits than other groups. So too, do those who have cleaner environments in which to adapt. Reducing outdoor concentrations, through policy addressing climate change or air pollution, reduces the need to adapt and protects those who cannot adapt. However, the studies herein show that behavioral change must also be considered, as it can either offset or amplify health improvements from ambient pollution reduction.