Researchers find that wildfire smoke poses neurological hazards

Inhaled microscopic particles from wood smoke can work their way into the bloodstream and reach the brain, putting people at risk for premature aging and various forms of dementia, depression, and even psychosis

Satellite photo, smoke from California fires
Satellite photo, smoke from California fires at 7:01 p.m. PDT Aug 4, 2021.

The research outlined below by the University of New Mexico Health Sciences Center is further evidence of the importance of smoke management. Land managers, agency administrators, and incident management teams need to constantly consider methods of reducing smoke exposure to firefighters and the downwind population when planning, conducting, or suppressing wildfires and prescribed burns.


Woodsmoke from massive wildfires burning in California shrouded much of the West last summer, making it harder for people suffering from respiratory illnesses to breathe.

Those respiratory consequences can be dangerous — even life-threatening — but Matthew Campen, PhD, a professor in The University of New Mexico College of Pharmacy, sees another hazard hidden in the smoke.

In research published online this week in the journal Toxicological Sciences, Campen and his colleagues report that inhaled microscopic particles from woodsmoke work their way into the bloodstream and reach the brain, and may put people at risk for neurological problems ranging from premature aging and various forms of dementia to depression and even psychosis.

“These are fires that are coming through small towns and they’re burning up cars and houses,” Campen says. Microplastics and metallic particles of iron, aluminum and magnesium are lofted into the sky, sometimes traveling thousands of miles.

In the research study conducted last year at Laguna Pueblo, 41 miles west of Albuquerque and roughly 600 miles from the source of wildland fires, Campen and his team found that mice exposed to smoke-laden air for nearly three weeks under closely monitored conditions showed age-related changes in their brain tissue.

The findings highlight the hidden dangers of woodsmoke that might not be dense enough to trigger respiratory symptoms, Campen says.

As smoke rises higher in the atmosphere heavier particles fall out, he says. “It’s only these really small ultra-fine particles that travel a thousand miles to where we are. They’re more dangerous because the small particles get deeper into your lung and your lung has a harder time removing them as a result.”

When the particles burrow into lung tissue, it triggers the release of inflammatory immune molecules into the bloodstream, which carries them into the brain, where they start to degrade the blood-brain barrier, Campen says. That causes the brain’s own immune protection to kick in.

“It looks like there’s a breakdown of the blood-brain barrier that’s mild, but it still triggers a response from the protective cells in the brain — astrocytes and microglia — to sheathe it off and protect the rest of the brain from the factors in the blood,” he says.

“Normally the microglia are supposed to be doing other things, like helping with learning and memory,” Campen adds. The researchers found neurons showed metabolic changes suggesting that wildfire smoke exposure may add to the burden of aging-related impairments.

The research team included colleagues from the College of Pharmacy and the UNM Departments of Neurosciences, Geography & Environmental Studies, and Earth and Planetary Sciences, as well as researchers at Arizona State University, Michigan State University and Virginia Commonwealth University.


Story provided by University of New Mexico Health Sciences Center. Original written by Michael Haederle.

Journal Reference:

David Scieszka, Russell Hunter, Jessica Begay, Marsha Bitsui, Yan Lin, Joseph Galewsky, Masako Morishita, Zachary Klaver, James Wagner, Jack R Harkema, Guy Herbert, Selita Lucas, Charlotte McVeigh, Alicia Bolt, Barry Bleske, Christopher G Canal, Ekaterina Mostovenko, Andrew K Ottens, Haiwei Gu, Matthew J Campen, Shahani Noor. Neuroinflammatory and neurometabolomic consequences from inhaled wildfire smoke-derived particulate matter in the Western United States. Toxicological Sciences, 2021; DOI: 10.1093/toxsci/kfab147

Thanks and a tip of the hat go out to Gerald.

Smoke from Alisal Fire triggers air quality advisory for Southern California

The smoke will worsen Thursday afternoon and evening

Wildfire smoke forecast, Southern California
Wildfire smoke forecast for 7 p.m. Oct. 14, 2021. NOAA.

Residents along the Southern California coast are seeing the effects of the Alisal Fire in the air they are breathing. On Thursday the South Coast Air Quality Management District issued a special air quality advisory for smoke that will be worsening during the afternoon.

Heavier concentrations of the smoke are expected to move into the counties of Orange, Riverside, San Bernardino, and L.A. Thursday afternoon and evening.

The Alisal Fire has burned more than 16,000 acres 19 miles west of Santa Barbara.

Smoke from California wildfires increases doctor visits and blocks sun from crops

Study shows N95 masks can reduce hospital visits for smoke inhalation by up to 40 percent

Smoke on the Monument Fire
Smoke on the Monument Fire, Sept. 18, 2021. Photo by NRIMT2-FBAN.

Recent articles on MSN.com pointed out three different wildfire smoke related issues.

Smoke in California’s Central Valley increased doctor visits (Oct. 3 2021)

Dr. Praveen Buddiga, a local allergy and immunology specialist, says he saw an increase in patient visits on Friday due to the smoke sitting in the Valley.

“Today I’ve been seeing a lot of patients with cough, congestion, difficulty breathing and this is directly related to the air,” said Dr. Buddiga.

Dr. Buddiga said many of his patients have difficulty breathing, which is not surprising considering the smoke is even visible in satellite images taken from space.

Some masks can protect against wildfire smoke (Sept. 30, 2021)

Researchers found that N95 masks often used for protection from COVID-19, are effective in reducing the inhalation of wildfire smoke particles, and could reduce hospital visits for wildfire smoke inhalation by up to 40 percent. They found that surgical masks, primarily designed to keep sneeze and cough droplets from emerging in the air, do not not protect the wearer against a dangerous environment. Cloth masks used alone are also ineffective. While surgical masks by themselves were ineffective, combining them with a cloth mask to compensate for the surgical mask’s loose fit was about as effective as an N95 as long as the seal around mouth and nose was good.

Wildfire smoke is blocking Central Valley crops from the sun (Oct. 6, 2021)

…This smoke could cause some damage to the raisin and almond crops that are still drying out in the fields.

“Those two crops specifically need mother nature, as in the sun, to dry those crops out in the field, and that drying time is essentially eliminated right now with the smoke layer that we have,” said Ryan Jacobsen, CEO of the Fresno County Farm Bureau, “We’re just not seeing it, we aren’t seeing any drying taking place and that becomes very problematic especially for raisins because if they don’t dry they’re going to sit there and rot in the field. So, we’re hoping that this weather change we’re going to see take place in the next couple of days hopefully blows this smoke out of there and returns the sun to help us finish off this crop year.”

Jacobsen says the Farm Bureau’s other priority is the health and safety of farmworkers. For their protection, the bureau has been providing N95 respirators to agricultural employers.

Thanks and a tip of the hat go out to Jim.

EPA attempts to compare smoke impacts from wildfires and prescribed fires

Releases 438-page report

8:08 a.m. MDT Oct. 1, 2021

EPA study, prescribed fire and wildfire

The release of a 438-page study by the US Environmental Protection Agency to compare the smoke impacts from prescribed vs. wildfire is not a ground-breaking event that will change fire management.

Titled, “Comparative Assessment of the Impacts of Prescribed Fire Versus Wildfire (CAIF): A Case Study in the Western U.S.”, the large 28MB .pdf file can be downloaded here.

In January 2020, the Wildland Fire Leadership Council, an intergovernmental committee formed to support the implementation and coordination of Federal Fire Management Policy and chaired by senior leadership in the U.S. Department of Agriculture and Department of the Interior, requested and paid for the EPA to lead an assessment to characterize and compare the smoke impacts of prescribed fire and wildfire under different fire management strategies, including prescribed fire.

They evaluated two fires, the 3,000-acre Timber Crater 6 Fire that occurred in Oregon in 2018 and the 150,000-acre Rough Fire of 2015 in the Sierra NF, Kings Canyon National Park, and Sequoia NF of California. I could not find any indication that the researchers studied a prescribed fire, which usually burn with different fire behaviors than a wildfire.

The poorly edited report is not light reading and is a slog to wade through the hundreds of pages.

Many of the report’s “key insights” will not be a surprise to land managers (or anyone with a little common sense and exposure to fire management). Here are samples from Chapter 9, “Integrated Synthesis”:

  • Smaller wildfires produce fewer public health impacts than larger wildfires.
  • Convincing the public to evacuate or use air cleaners or HVAC filters to decrease exposure to PM2.5 can decrease public health impacts from smoke.
  • If a wildfire spreads into an area previously treated with prescribed fire it can reduce additional spread of the wildfire.
  • Smoke plumes that do not intersect with high population areas or last only a few days are less likely to have substantial health impacts than fires affecting larger populations for longer periods.

Update at 3:19 p.m. Oct. 1, 2021:

After publishing the article above, we heard from Bob Yokelson with the Department Chemistry at the University of Montana. He and others have produced data showing the differences between smoke produced by prescribed fires and wildfires. It’s all in their paper, “Aerosol Mass and Optical Properties, Smoke Influence on O3, and High NO3 Production Rates in a Western U.S. City Impacted by Wildfires.”

Here is the passage Mr. Yokelson sent us:

“We stress that there is now more than 1,000 hr of ground‐based data from Missoula, suggesting that a typical PM2.5/CO value for aged wildfire smoke at the surface is about half the value in fresh to moderately aged well‐lofted wildfire plumes (Collier et al., 2016; Garofalo et al., 2019; Liu et al., 2017). One airborne wildfire study by Forrister et al. (2015) at lower latitudes and sampling elevations than the other airborne studies is consistent with the downwind net evaporation we apparently observe in Missoula.

“We also stress that, despite the evidence for PM evaporation during aging, there are strong data discussed next, supporting the idea that wildfires produce more PM than spring or fall prescribed fires on a per fuel burned or per area burned basis. Liu et al. (2017) reported that EFs for PM1.0 (gPM1.0/kg fuel burned) are almost four times higher in wildfires (27.1 ± 6.1) than spring and fall prescribed fires (7.3 ± 4.2; May et al., 2014). Our 2 year average ΔPM2.5/ΔCO ratio in aged wildfire smoke (~0.117) is ~1.7 times higher than implied for aged, fall western montane prescribed fire smoke (~0.07) based on May et al. (2014, 2015), suggesting that a remnant of the difference in initial PM emissions can survive aging. Fuel consumption in spring/fall prescribed fires at the national level is typically 7.2 ± 2.7 Mg ha−1 (Yokelson et al., 1999, 2013) as opposed to 34.6 ± 9.9 Mg ha−1 on wildfires (Campbell et al., 2007; Santín et al., 2015).

Combining the emissions and fuel consumption differences implies that wildfires emit 18 ± 14 times more PM per area burned. Although prescribed fires cannot simply replace all wildfires (Schoennagel et al., 2017; Turner et al., 2019), their potential to reduce the level of wildfire impacts deserves more attention. In addition, incorporating higher wildfire initial emissions and temperature‐dependent, post emission OA evaporation may improve models of wildfire smoke impacts (Nergui et al., 2017).”

Citation:
Selimovic, V., Yokelson, R. J., McMeeking, G. R., & Coefield, S. (2020). Aerosol mass and optical properties, smoke influence on O3, and high NO3 production rates in a western U.S. city impacted by wildfires. Journal of Geophysical Research: Atmospheres, 125, e2020JD032791. https://doi.org/10.1029/2020JD032791

Wildfire smoke and air quality, August 31, 2021

Forecast for wildfire smoke
Forecast for wildfire smoke at 12:01 a.m. PDT Sept. 1, 2021.

Above is the forecast for the distribution of smoke from wildfires at 12:01 a.m. PDT September 1, 2021.

Below is the current air quality status, obtained at 2:22 p.m. PDT August 31, 2021 from AirNow.gov. There is not much pollution in the East, due in part to Hurricane Ida.

Air quality (Ozone, PM2.5, & PM10) at 2:24 p.m. PDT Aug. 31, 2021
Air quality (Ozone, PM2.5, & PM10) at 2:24 p.m. PDT Aug. 31, 2021. AirNow.gov