SEMINAR: Quantifying the public-health benefits of exposure to the natural environment

A growing body of literature suggests that exposure to the natural environment may provide a range of public-health benefits. However, methodological limitations means that claims about the health benefits of nature have been treated with caution by public-health researchers and practitioners. In particular, the natural environment is prone to confounding by other drivers of public health outcomes. In addition, the natural environment is often difficult to experimentally manipulate.

I will present findings from two studies that have addressed these methodological challenges in a novel way. In the first study, we used the spread of an invasive trees pest—the emerald ash borer—as a natural experiment to study the impact of a major change in the natural environment on public health. We found that US counties infested with the emerald ash borer had higher rates of cardiovascular and lower-respiratory mortality, and this effect increased in both magnitude and significance as an infestation progressed.

In the second study we used 347 samples of tree moss to identify and map sources of atmospheric heavy metals in Portland, Oregon. We found that—unknown to environmental regulators—two stained glass manufacturers were emitting cadmium and arsenic at levels that posed an immediate health risk. Our findings led to a major overhaul of environmental regulations at the state and federal level and showed that bio-indicators may be a cost-effective complement to traditional instrumental air-quality monitoring.