Category Archives: Low-cost sensors

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


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

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

Communal support for residents suffering from smoky air

Public officials in several western regions and communities are identifying ways to shield residents from smoke-filled air and to offer communal support when  residents are faced with poor air quality and the impact of climate change. A recent article in the Christian Science Monitor looks at initiatives such as the city of Seattle’s program in which five public buildings were set up as clean-air centers where residents can take shelter if summer wildfire smoke impacts air quality. Dan Jaffe, along with Alex Margarito (UW Bothell graduate) and Rebecca Rickett (UW Bothell student), are working with the city to analyze the effectiveness of these clean-air centers.

In other action, two US senators are introducing “legislation that would provide federal funding to communities to improve ventilation systems in public buildings and set up emergency smoke shelters.” A California state assemblywoman also proposed a state program to improve “ventilation systems in schools, libraries, and community and senior centers” so that residents have a safe haven when air quality is poor.

The particulate matter in smoky air is a health hazard that affects everyone but hits the most vulnerable, including children and the elderly, the hardest. In addition to the physical toll, residents facing wildfire smoke may experience negative mental health effects. Researchers at the University of Montana in Missoula Human Dimensions Lab  found that bringing residents together can help alleviate anxiety. As Libby Metcalf, lab co-director, says, “There’s a need to have a community gathering space to share stories about wildfire…It’s a way for people to feel like they don’t have to face what’s happening on their own.” The American Psychological Association also identifies communal support as an essential remedy to the depression and desolation that people may experience as they cope with the impact of climate change. Officials such as Julia Reed, senior policy adviser to the Seattle mayor, also see the need to bring people together: “All of us see climate change happening right outside our window,” she says. “Coming together is a way to make people feel less helpless.”

Read the full article here.

Wildfire smoke impacts indoor air quality

The last two years in Seattle were the worst on record for wildfire smoke and its impact on air quality. Smoke-filled air contains fine particles of 2.5 microns in diameter or smaller (PM2.5), which pose a significant health risk because they can move deeply into the lungs. When the air quality outside is “unhealthy for all” according to the EPA because the PM2.5 level is above 55 μg/m3, residents are told to remain inside as much as possible. This occurred 2 days in 2017 and 4 days in 2018. The very young, elderly, and sensitive individuals are particularly at risk to air quality with PM2.5 above 35 μg/m3. However, is the air inside that much better? Even with the windows and doors closed, is the air inside at a healthy level during a smoke event?

Worst ever smoke in Seattle on Aug. 21, 2018

Seattle experiences the worst smoke ever (PM2.5 of 110 μg/m3) on August 21, 2018. Photo courtesy of Dan Jaffe.

Last August during a smoke event in the region, Dan Jaffe was curious about the air quality in his office at UW Bothell and elsewhere on campus. He and Alex Margarito, a recent UW Bothell grad who was then a student in Jaffe’s research group, took measurements in Jaffe’s and other offices on campus, in classrooms, and in Jaffe’s Seattle home. They discovered that the inside air was often bad. On August 22, Jaffe measured PM2.5 of 100 μg/m3 inside his office in Discovery Hall at UW Bothell. “You couldn’t tell that it was that bad inside until you actually took the measurements,” Margarito said. “What we found is that the air inside buildings eventually can get near the same levels as what’s outside. So sitting inside is not going to do that well for you.”

This summer Alex Margarito and Rebecca Rickett, a UW Bothell Biochemistry major, are working with Seattle Parks and Recreation to monitor and analyze indoor and outdoor air quality. This project is part of Seattle’s pilot program in which they installed enhanced filtering at five buildings in the city to offer residents an oasis if a smoke event hits the area. The city has also installed several low-cost sensors to measure air quality in several locations around the city.

Joelle Hammerstad, sustainable operations manager at Seattle Parks and Recreation, is excited that the city is partnering with Dan Jaffe and Margarito and Rickett on this project. “Bigger picture, we’re trying to understand the situation at our facilities when we have poor air quality,” Hammerstad said. “Are the measures effective?”

The city is also thinking about climate change. “This is a critical, pivotal moment where we’re refocusing how we’re thinking about climate change. We’re thinking about resilience, adaption,” Hammerstad said. “How do we help front-line communities get through this—communities that don’t have the resources to easily adapt to a changing climate?”

Read more on the UW Bothell website.

When Seattle experiences another smoky summer, the city is ready with 5 clean air centers

City officials in Seattle have invested in 5 facilities with free clean and cool air for residents if and when wildfires fill local skies with smoke this summer. A recent article in the Washington Post online describes Seattle’s new program. Seattle is retrofitting 5 facilities that had central cooling with advanced air filtration systems. These systems will be able to filter out microscopic particulates that are especially dangerous for children, elderly people, and those with heart or respiratory conditions. Indoor air sensors will also be installed in the city facilities to measure the air quality. Dan Jaffe, Alex Margarito-Lopez (recent UW Bothell graduate), and Rebecca Rickett (UW Bothell student) will be working with the city to interpret data from these sensors.

In the past two summers, Seattle experienced increased air pollution from wildfire smoke, including 4 days last summer that reached levels of fine particulate matter that were unhealthy for all individuals. Most homes in Seattle do not have air conditioning or air filtration systems. Many residents rely on opening the windows to cool their homes in the summer. When the outside air is polluted with smoke, opening windows leads to a house filled with polluted air. The new clean air centers will offer residents somewhere to go to get out of the polluted air.

Wildfires in the West have been increasing in recent years. A major factor in the worsening wildfire picture is human-driven climate change, which is causing drier and warmer conditions. Seattle Mayor Jenny Durkan recognized that local governments need to step up “to be ready for the climate changes we’re experiencing in Seattle.” These centers are part of an effort to address climate change’s impacts.

The wildfire outlook is “strong wildfires, much larger than normal,”  Dan Jaffe says. “It’s going to get worse. How much worse we don’t know, but we need to adapt. Whether that’s thinking about clean air, cool spaces to go to during the daytime, or whether that means shoring up beaches, or whatever it means, communities across the country need to adapt to climate change.”

Read the full Washington Post Energy 202 article.