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The hazy days of summer – wildfire season strategies

aerial view of Washington with blanket of smoke over it

By Rebecca Phillips, Washington State Magazine

It’s no secret that wildfires are on the rise throughout the western United States. Come summer, the plumes of gray-brown smoke seem to arrive weeks earlier and often linger well into fall. The smoke irritates sinuses, clings to clothes, and despite your efforts, seeps into homes and cars like an ever-present smoldering campfire.

On those haze-filled days, people often wonder, “Is it safe for the kids to play outside? To hold a neighborhood BBQ? What about those with asthma or other respiratory problems?”

Engineers at the Washington State University Laboratory for Atmospheric Research (LAR) are helping provide answers through a powerful computer modeling system called AIRPACT, which predicts daily air pollution levels for the Pacific Northwest, including wildfire smoke.

In response to growing public health concerns, the AIRPACT team recently expanded their wildfire smoke forecasting capabilities and is also developing early-warning alerts for those with respiratory health issues.

It’s a welcome move after last summer, when the Spokane Clean Air Agency recorded the region’s worst air quality since monitoring began 20 years ago. For several days in September, much of Eastern Washington was blanketed with thick mud-yellow smoke that sent air quality readings into the very unhealthy zone—and people scrambling for N95 masks.

Though the severity of wildfire seasons varies, scientists say the number of smoky days has been trending upward for the last decade and is expected to continue. The reasons are complex, but it’s generally agreed that average temperatures are rising and staying warmer longer due to climate change. The result is often more rain than snow during winter, which spurs spring vegetation growth and allows insect pests to survive. The combination of drought, dry fuel, and pests can turn what should be a normal fire year into something extreme.

The looming question, for many people, is how to adapt their daily lives to endure weeks or months of smoky air pollution while minimizing adverse health effects.

Joseph Vaughan, research associate professor in civil and environmental engineering, says smoke forecasts are posted on the AIRPACT website by 7 a.m. each day and can help with decision-making and day-planning. The system models several components of wildfire smoke, with a focus on particulate matter that is 2.5 microns or less in diameter, called PM2.5. In comparison, the average hair is 10 microns wide.

These tiny smoke particles stay suspended in the air and are small enough to get deep into the lungs where they cause irritation and inflammation, says Vaughan. According to the Environmental Protection Agency, particle pollution is carcinogenic and linked to serious health problems including respiratory disease, asthma attacks, cardiac arrhythmias, heart attacks, strokes, and early death.


Map of northwest with colors indicating smoke and fire.
Detail of the online AIRPACT-5 Dynamic Map which forecasts air quality in the Pacific Northwest. (Courtesy WSU Laboratory for Atmospheric Research)

PM 2.5 is one of six pollutants reflected in the EPA’s Air Quality Index, or AQI, and regulated by the Clean Air Act. The AQI, available to the public on, shows current air pollution levels using colors and a scale running from 0 to 500. Good air quality, for example, is shown in green and runs between 0 to 50. Yellow is moderate at 51 to 100, orange is unhealthy for sensitive groups at 101 to 150, red is unhealthy for everyone at 151 to 200, purple is very unhealthy for everyone at 201 to 300, and maroon is hazardous at 301 to 500.

In Spokane last September, the AQI for PM2.5 reached 256—purple level and the highest ever recorded.

Vaughan says AQI is based on weather monitoring and forecasts while AIRPACT uses a computer model that brings in meteorology and emissions data to simulate air pollution conditions as they evolve over time. The AIRPACT team wants to use the model to provide practical information for widespread public use.

To that end, Vaughan and his colleagues recently teamed up with the Washington State Department of Ecology and Washington State Department of Health to create a program called CENSE — or Cardiopulmonary EveNts from Smoke Estimator.

Using AIRPACT forecasting, CENSE will alert individuals when air quality is predicted to deteriorate and could trigger specific health emergencies. Plans are in the works for a website, subscriber function, and smartphone apps.

CENSE calculates values that relate the average 24-hour PM2.5 level to incidence of human health conditions such as asthma and chronic obstructive pulmonary disease (COPD). For example, Vaughan says there is a specific value for asthma patients under age five, another for the general population, and one for those over age 65.

“Our subscriber function will text, call, or email you with the day’s warnings for the conditions you’ve signed up for,” he says. “If you have a child with asthma, you might want an alert whenever there’s a 20 percent increase in the risk of an event. Or a 50 percent increase for a parent with COPD.”

CENSE ties in nicely with the work of WSU civil and environmental engineering professor and LAR member Von Walden, who leads air quality research for the Urbanova project in Spokane’s U-District. Urbanova is a consortium of businesses and innovators who are using smart city technologies to improve services and infrastructure in Spokane.

“The smart city idea is using state-of-the-art sensors in intelligent ways to improve health and well-being of citizens,” says Walden.

Last year, he and his colleagues mounted air quality sensors on three streetlamps as part of the Avista smart streetlight project.

“This spring, we installed six more sensors—this time on rooftops in the U-District,” Walden says. “We also put in a very sophisticated suite of air quality instruments as a reference site at WSU Spokane.”

Their plan is to monitor air quality at the street and neighborhood level with an emphasis on winter air stagnation and wildfire smoke. As they gear up for what could be another smoky fire season, Walden says they hope to collect data that will benefit the general public.

“Smoke can have serious health effects, so we’re making measurements to better understand the exposure of Spokane’s citizens,” he says. “By providing people with more information during smoke events, we hope that they will be able to make better decisions regarding their personal health.”

See the Washington State Magazine site for this article and, at the bottom, “10 tips to cope with wildfire smoke.”



  • Rebecca Phillips, writer, Washington State Magazine, 509-335-2346,

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