By Ana G. Rappold
There are many studies demonstrating associations between cardio-respiratory health and air pollution. However, most have focused on fossil fuels and urban pollution. Less is known about the health effects of wildfires, which in the U.S. account for 35% of fine particulate matter and can produce concentrations of air pollutants orders of magnitude larger then urban pollution.
That’s where my work comes in.
My colleagues and I recently published the results of research we conducted examining the effects of wildfire exposure on cardio-respiratory health, We used satellite measurements to track the plume of smoke air quality data in an area exposed to a wildfire, and then combined that information with a nearly comprehensive record of emergency room visits.
We found a consistent increase in relative risk for asthma, COPD, pneumonia, acute bronchitis and heart failure in the counties most affected by the smoke. In comparison, no such changes were observed in neighboring counties unaffected by wildfires.
Wildfires are associated, for many of us, with hot and dry places of the Southwest and heavily wooded remote regions of the Rocky Mountains. They are part of a natural life cycle in most ecosystems and are necessary and healthy parts of the ecosystem. But a changing climate threatens to disrupt historic patterns, and potentially threaten human health.
In North Carolina where we conducted our study, for example, we experienced six major wildfires in just two years, far exceeding the historic rate. Extensive ditching and draining of the peat lands combined with a prolonged drought has left the peat lands vulnerable to ignition, which in the case of our study area was lightning strikes.
For anyone who lived east of hwy 85 in NC, it would have been hard not to notice the smell of smoke coming from hundreds of kilometers away. These fires produced massive amounts of ground level smoke, affecting the life of local residents and the activities of seasonal tourists. Moreover, the fires cumulatively produced a bill of more then $65 million dollars in direct fire suppression costs.
Our work is helping us better understand the impacts of wildfire. It is important that we understand these impacts so we are better able to educate medical practitioners and the public of possible health risks involved in wildfires, particularly as they are expected to become more frequent in the future. As we learned, this can be critical information for people with asthma or cardio-vascular problems. What we learn will help us work with professionals from other disciplines so that we can better protect human health.
About the Author: Ana G. Rappold is a statistician and an investigator at EPA’s Environmental Public Health Division in Chapel Hill, NC.