As part of its Clean Thinking collection, Taylor & Francis is providing free access to a collection of articles on clean thinking for climate change. Included in the collection is the critical review “Wildfire and prescribed burning impacts on air quality in the United States,” published in the Journal of the Air & Waste Management Association in June 2020. Access is free until April 30, 2022.
Popular Science recently took a look at how wildfires are polluting our air. They cited research about the increase in two pollutants due to wildfires: PM2.5 (fine particulate matter less than 2.5 micrometers in size) and ozone. This research, conducted by Dmitri Kalashnikov, a doctoral student in environmental science at Washington State University Vancouver, found the co-occurrence of these two pollutants has increased significantly in the last 20 years in the western U.S. during July–September, as wildfires have increased.
Dan Jaffe noted that understanding the relationship between PM2.5 and ozone levels isn’t straightforward. He and Jaffe Group researchers have previously found that the most extreme levels of PM2.5 and ozone tend not to occur on the same days. He says that the new paper is still “definitely a step forward.”
Understanding and responding to the increase in wildfires and their unhealthy pollution are important issues for western communities and policy makers.
“The impact of wildfire smoke on ozone production in an urban area: Insights from field observations and photochemical box modeling”
In this recently published paper, postdoctoral research associate Matt Ninneman and Dan Jaffe examined the effect of wildfire smoke on ozone (O3) production at an urban site in Bakersfield, CA. They used data from smoky and non-smoky weekdays in summer 2018. During this period, there were several active wildfires in northern California. The authors utilized a photochemical box model to analyze the data. The box model simulations indicate that maximum O3 production rates were about two times faster on smoky weekdays compared to non-smoky weekdays. Model sensitivity tests for smoky weekdays showed that (1) O3 was sensitive to both oxides of nitrogen (NOx) and volatile organic compounds (VOCs) and (2) aldehydes significantly affected O3 formation. Their results suggest that “a combination of anthropogenic VOC and NOx reductions will be the most effective strategy for decreasing O3 on typical non-smoky days.” However, only reductions in NOx are expected to have a significant impact on lowering O3 concentrations on typical smoky days, since VOC levels in smoke plumes are high.
“Observed relationship between ozone and temperature for urban nonattainment areas in the United States”
In a second recently published paper, Matt Ninneman and Dan Jaffe investigated the observed relationship between ground-level ozone (O3) and temperature from 1995 to 2020 at 20 U.S. cities that violate regulatory requirements for ground-level O3. They found that the median slope of the ground-level O3 versus temperature relationship declined in all regions, and the correlation between ground-level O3 and temperature weakened over time in the eastern and midwestern U.S. In the western U.S., ground-level O3 has declined more slowly and the correlation between ground-level O3 and temperature has changed negligibly due to the combined influence of high background O3 and wildfire smoke. This suggests that meeting regulatory requirements for ground-level O3 in the western U.S. will be more challenging than in other parts of the country.
The Washington Post interviewed Dan Jaffe for a recent article about the benefits of air purifiers against airborne particles such as those from coronavirus and also wildfires. The article offers advice on what to look for in an air purifier and how to use one. Their advice in a nutshell: use HEPA filters, fit the purifier to the space, set it up correctly, and use the purifier in the rooms where people are. And one more thing—there is an option that is cheaper than spending $200–1000 for a purifier! At the end of the article, they cite the Jaffe Group’s research into using a standard box fan with an attached MERV-13 furnace filter to clean particulate matter from the air. Making a simple air purifier is an easy project you can do at home. The article also mentions that wearing masks is important.
Last summer was a smoke-filled one in Washington State. Will this summer be similar? Well, the drought conditions in Washington State have led to forests and grasslands filled with wildfire fuel. If you live in the Pacific Northwest, now is the time to prepare for the possibility of a smoky summer. Dan Jaffe was interviewed by KUOW recently and advised residents to get prepared. “You don’t have to spend a lot of money to actually do a pretty good job of protecting your indoor air quality.” You can make a simple smoke filter for your home with a box fan and a furnace filter.