Health Impacts of Invasive Species Through an Altered Natural Environment: Assessing Air Pollution Sinks as a Causal Pathway

Invasive alien species impact environmental quality by disrupting biodiversity, vegetation cover, and displacing native flora and fauna. This can affect human health outcomes. For example, the invasive emerald ash borer (EAB) has led to the destruction of millions of ash trees, one of the most common tree species in the US. Since trees are an important source of air pollution sinks, EAB-caused ash dieback may affect human health through changes in air quality. The quasi-random nature of EAB detections and consequent changes in various air pollution levels allow us to analyze differences in mortality rates for individuals living in counties where the beetle has been found relative to individuals in contemporaneously beetle-free counties. Results suggest that EAB are associated with lagged increases in pollutant concentrations ranging from 9.2 to 46.2%. A 2SLS fixed effects model indicates that EAB-induced air pollution is associated with increases in rates of cardiovascular mortality of 6.2/year-32.6/year per 100,000 people and increases in respiratory mortality of 1.9/year-3.9/year per 100,000. Impacts are greatest for children and young adults. At its peak impact, EAB-induced air pollution resulted in $4.8-$21.6 billion in annual mortality costs over 2002-2014 in the 24 US states in the study area. This study has important abatement policy implications.