Old smoke plumes from wildfires may still affect climate

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The UC Davis team sets up instruments for real-time ambient sampling at the Mount Bachelor Observatory in Oregon. Graduate student Christopher Niedek (front) sets up a particle generation system while Qi Zhang (middle) tunes a soot particle aerosol mass spectrometer and graduate student Peng Sun works on the line of ‘sampling. Credit: Ryan Farley/UC Davis

According to a study from the University of California, Davis, aerosols carried in smoke plumes from wildfires dating back hundreds of hours can still affect the climate.

The research, published in the journal Environmental science and technologysuggests that emissions from wildfires even 10 days old can affect the properties of aerosols, suspended liquids, or particles that are essential for cloud formation.

Research on aerosol and particulate pollution related to wildfires has most often focused on the first few hours of smoke plumes, not several days later after the smoke has moved to other areas. .

Improved modeling

This research helps fill a knowledge gap and can inform future predictions of the climate and atmospheric effects of wildfires during the aerosol lifetime, especially in rural or pristine areas where the air is relatively clean, a said Qi Zhang, professor of environmental toxicology and lead author of the study.

“These parameters are really useful for atmospheric and chemical models,” she said. “It’s a very important element in solving climate effects. Capturing these characteristics is extremely critical.”

Zhang, Ph.D. Student Ryan Farley and others spent time in 2019 at Mount Bachelor Observatory atop an Oregon volcanic mountain. That year was relatively quiet in terms of wildfires, but smoke plumes and aerosols were still observed. Some were at least 10 days old and came from as close as Northern California and as far away as Siberia, Russia.

The properties and chemical composition of aerosols can do a number of things: scatter or absorb solar radiation affecting temperature, seed clouds to produce rain or snow, or change the reflectivity of clouds, all of which affect all climate.

Ancient smoke plumes from wildfires may affect climate

Professor Qi Zhang of UC Davis tunes a laser vaporizer to the Soot Particle Aerosol Mass Spectrometer at Mount Bachelor Observatory to optimize detection of particles containing black carbon. Credit: Christopher Niedek/UC Davis

Aerosol properties change with age

Scientists found that particle concentrations were low, but oxidized organic aerosols from burning biomass, such as trees, grasses and shrubs, were detected in all samples.

The aerosols, which have a life cycle of about two weeks, were larger in older samples than those found soon after a fire started.

“The properties of the smoke determine the effects on the climate,” Zhang said. “Really aged aerosols can behave very differently than fresh aerosols. You want to capture these aerosols throughout their lifetime to properly account for the effects.”

Aerosols in the background

Older aerosols produced by wildfires may be present but not evident and still affect climate.

“It’s not something you notice, but it’s in the background,” she said.

Knowing that this information is becoming increasingly important as “biomass burning has become more and more common,” Zhang said.

Shan Zhou and Sonya Collier of UC Davis also participated in the research, as did scientists from the University of Montana and the University of Washington.


Wildfires devastate the land they burn and also warm the planet


More information:
Ryan Farley et al, Persistent Influence of Wildfire Emissions in the Western United States and Characteristics of Organic Aerosols Burning Aged Biomass in Clean Air Conditions, Environmental science and technology (2022). DOI: 10.1021/acs.est.1c07301

Quote: Older Wildfire Smoke Plumes May Still Affect Climate (2022, March 23) Retrieved March 23, 2022 from https://phys.org/news/2022-03-older-wildfire-plumes-affect-climate .html

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