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Jaffe Group

Category: Research

Highlights from 4 Papers in 2022

In 2022, Jaffe Group members authored or co-authored 7 papers. Here are highlights from 4:

1.            Sedlacek  A.J. Lewis E.R., Onasch T.B., Zuidema P., Redemann J., Jaffe D, and Kleinman L.I. “Using the Black Carbon Particle Mixing State to Characterize the Lifecycle of Biomass Burning Aerosols.” Environmental Science & Technology, 56 (20), 14315-14325, http://10.1021/acs.est.2c03851, 2022.

In this analysis, a team, led by Art Sedlacek at Brookhaven National Lab, used data from the Mt. Bachelor Observatory and other sites to show how secondary organic aerosols and black carbon change as wildfire smoke ages.  This work has important implications for the climate forcing of smoke.

2.            Jaffe, D. A., Schnieder, B., and Inouye, D. “Technical note: Use of PM2.5 to CO ratio as an indicator of wildfire smoke in urban areas.” Atmos. Chem. Phys., 22, 12695–12704, https://doi.org/10.5194/acp-22-12695-2022, 2022.

In this analysis, Dan and coauthors show how the PM2.5/CO ratio can be used to track wildfire smoke in urban locations.

3.            Jaffe, D. A., Ninneman, M., & Chan, H. C. “NOx and O3 trends at U.S. non-attainment areas for 1995–2020: Influence of COVID-19 reductions and wildland fires on policy-relevant concentrations.” Journal of Geophysical Research: Atmospheres, 127, e2021JD036385. https://doi.org/10.1029/2021JD036385, 2022.

In this analysis, Dan and coauthors examined data from 32 Nonattainment areas in the US (cities that fail to meet the US ozone standard) to better understand the relationship between nitrogen oxides (mainly from vehicles) and Ozone.  The analysis showed how ozone was reduced in 2020 in the Eastern U.S. (due to COVID-19 related traffic reductions) but increased in the Western U.S. due to the large number and area of wildfires burning that year.

4.            Bernays, N., Jaffe, D. A., Petropavlovskikh, I., and Effertz, P. Comment on “Comparison of ozone measurement methods in biomass burning smoke: an evaluation under field and laboratory conditions” by Long et al. Atmos. Meas. Tech., 15, 3189–3192, https://doi.org/10.5194/amt-15-3189-2022, 2022.

In this analysis, Jaffe-group team member Noah Bernays and coauthors confirmed a significant interference in the measurement of O3 in smoke for some UV instruments. This interference was attributed to the use of manganese chloride as the scrubber material, for example in the Thermo Fisher’s 49i series ozone analyzers. Instruments employing manganese dioxide scrubbers did not show this interference.

Popular Science interviews Dan Jaffe on wildfire pollution

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.

Read the Popular Science article

Matt Ninneman and Dan Jaffe publish 2 new papers on ozone

“The impact of wildfire smoke on ozone production in an urban area: Insights from field observations and photochemical box modeling”

map of California showing Bakersfield site and fire locations
Map of California showing the locations of the Bakersfield Municipal Airport (BMA) site and the Ferguson, Natchez, Carr, Mendocino Complex, Donnell, and Hirz fires.

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.

Read the full paper in Atmospheric Environment

“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.

Read the full paper in Atmosphere

Air purifiers can help protect from COVID-19 and smoke

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.

Read the Washington Post article

Learn how to make an air purifier for your home

Jaffe elected to Washington State Academy of Sciences

Dan-Jaffe-in -snow-in-front-of-mountainCongratulations to Dan Jaffe on his election to the Washington State Academy of Sciences (WSAS)! Jaffe was elected by members of the WSAS and recognized “for leadership in monitoring and understanding the global transport of atmospheric pollutants from energy production, wildfire, and other sources, as well as science communication and service that has informed citizens and enhanced public policy.” Jaffe has been at UW Bothell since 1997 and is also a professor at UW Seattle in the Department of Atmospheric Sciences. His research focuses on atmospheric chemistry, ozone photochemistry, wildfire smoke, and the long-range transport of pollutants. He has operated the Mt. Bachelor Observatory research station in Bend, Oregon, since 2004.

New members to the WSAS were chosen for “their outstanding record of scientific and technical achievement, and their willingness to work on behalf of the Academy to bring the best available science to bear on issues within the state of Washington,” according to the WSAS press release.

The WSAS is a not-for-profit organization that provides expert scientific and technical information to inform issues and public policy making in the state of Washington. It was established in 2005 and currently has over 300 elected members, all residing in Washington State.

Smoky summer ahead?

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.

Listen and read the KUOW report

Learn how to make an air purifier for your home

 

Low-cost filtration method improves air quality during smoke events—see the new paper

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A new paper by group members Dr. Nate May, Clara Dixon, and Dr. Dan Jaffe evaluates the effectiveness of low-cost air filter units during wildfire smoke events. The increased wildland fire activity in the western US in recent years produces high concentrations of fine particulate matter (PM2.5), which negatively affects the health of millions of people. During wildfire smoke events, staying indoors is often recommended. However, how good is indoor air quality during smoke events? The authors looked at PM2.5 measurements from the PurpleAir sensor network, a publicly available network of low-cost air quality sensors located indoors and outdoors. They also analyzed the effectiveness of residential filter units in reducing indoor PM2.5. One low-cost DIY filtration method consists of attaching a Minimum Efficiency Rating Value-13 (MERV-13) fan filter to a standard box fan. This method was found to be highly effective at reducing indoor PM2.5 when recirculating air in a single room.

Read the full paper in Aerosol and Air Quality Research

See the video on how to make your own air purifier at home

A new age of wildfires

wildire in Pacific Northwest
Credit: Mark Stone/University of Washington.

A new article on the University of Washington website looks at the growing severity of wildfires and the broad research that the university is doing on their impacts. The article highlights the work that we do on wildfires’ effects on air quality. Also featured is the Joel Thornton lab at UW Seattle and the work of other UW researchers who study wildfires and forests.

Faculty and students install instruments at Mt. Bachelor Observatory.
Claire Buysse and Dan Jaffe set up radiometers to measure UV light on the top of Mt. Bachelor Observatory, August 2019. Credit: Mark Stone/University of Washington.

In the summer of 2019, UW photographer Mark Stone visited Mt. Bachelor Observatory, as well as other research sites, and captured the UW’s research in stunning photographs.

Read the article.

Mt. Bachelor Observatory
Mt. Bachelor Observatory research site at the top of Mt. Bachelor, Bend, Oregon, August 2019. Credit: Mark Stone/University of Washington.

The “smoke apocalypse” and indoor air quality: Media reports with Dan Jaffe

In September, Seattle and the Puget Sound region recorded the worst air quality ever. For example, in the Georgetown neighborhood of Seattle it was 314 on the air quality index on September 17. During our area’s recent smoke apocalypse, Dr. Dan Jaffe has been a frequent media guest. He has been interviewed by the Seattle Times, Crosscut, KIRO7, KOMONews, KOMOAM, KING5, and Q13Fox. Dan discussed his work on indoor air quality during the wildfire season and showed how to make a very effective DIY air purifier using a box fan and a MERV 13 furnace filter.

See links to all of the articles and videos along with descriptions

Welcome, Matt Ninneman, new post-doc!

In the midst of the COVID-19 pandemic, our research is continuing. And now our work will be strengthened by the addition of post-doctoral scholar Matt Ninneman!

Matt comes to us from the State University of New York at Albany (NY), where he received his PhD in Atmospheric Science. His dissertation was titled “Ozone and reactive oxidized nitrogen chemistry in the northeast U.S.” Matt’s research experience in ozone photochemistry and air quality and box modeling will be a valuable addition to our research. In his position at UW Bothell, Matt will be studying the effect of wildfire smoke on ozone production in urban areas using the Framework for 0-D Atmospheric Modeling (F0AM) box model and assisting with research at Mount Bachelor Observatory.

Matt is originally from Charlotte, NC, and received his BS in meteorology from North Carolina State University in Raleigh. He is new to the West Coast and looks forward to exploring the many bike trails in the Seattle/Bothell area. His other hobbies include running, playing basketball, reading, and closely following the Boston Red Sox and the Atlanta Braves in baseball and the Charlotte Hornets in basketball.

Even though we are unable to welcome Matt in person, we are delighted to have him join our group and look forward to future non-Zoom get-togethers. Welcome, Matt!