Older wildfire smoke plumes can affect climate

Date:
March 23, 2022
Source:
University of California - Davis
Summary:
Aerosols carried in wildfire smoke plumes that are hundreds of
hours old can still affect climate, according to a new study.



FULL STORY ========================================================================== Aerosols carried in wildfire smoke plumes that are hundreds of hours old
can still affect climate, according to a study out of the University of California, Davis.


==========================================================================
The research, published in the journalEnvironmental Science and
Technology, suggests that wildfire emissions even 10 days old can affect
the properties of aerosols -- suspended liquid or particles that are
key to cloud formation.

Research in aerosols and particulate matter pollution related to wildfires
has most often focused on the early hours of smoke plumes, not several
days later after smoke has traveled to other areas.

Enhancing modeling This research helps fill in a knowledge gap and can
inform future predictions about the climate and atmospheric effects
of wildfire over the lifetime of aerosols, particularly in rural or
pristine areas with relatively clean air, said Qi Zhang, an environmental toxicology professor and lead author of the study.

"These parameters are really useful for atmospheric and chemical models,"
she said. "It's a really important component to solving the effects on
climate. To capture those characteristics is super critical." Zhang,
Ph.D. student Ryan Farley and others spent time in 2019 at the Mount
Bachelor Observatory atop a volcanic mountain in Oregon. That year was relatively calm in terms of wildfire, 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 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 climate.

Aerosol properties change with age Scientists found that particulate
matter concentrations were low, but oxidized organic aerosols from
burning biomass -- such as trees, grasses and shrubs - - were detected throughout the samples.

The aerosols, which have a life cycle of about two weeks, were larger
in aged samples compared to those found shortly after a fire starts.

"The properties of the smoke determine the effects on the climate,"
Zhang said.

"The really aged aerosols can behave very differently than the fresh
ones. You want to capture these aerosols over the lifetime to properly
account for the effects." Aerosols in the background


========================================================================== Older aerosols produced by wildfires can be present but not obvious and
still affect climate.

"It's not something you just notice but it's in the background," she said.

Knowing that information becomes ever more important as "biomass burning
has become more and more frequent," Zhang said.

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

The National Science Foundation, the U.S. Department of Energy's
Atmospheric System Research Program, the California Agricultural
Experiment Station and UC Davis funded the research.


========================================================================== Story Source: Materials provided by
University_of_California_-_Davis. Original written by Emily Dooley. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Ryan Farley, Noah Bernays, Daniel A. Jaffe, Damien Ketcherside,
Lu Hu,
Shan Zhou, Sonya Collier, Qi Zhang. Persistent Influence of Wildfire
Emissions in the Western United States and Characteristics of Aged
Biomass Burning Organic Aerosols under Clean Air Conditions.

Environmental Science & Technology, 2022; 56 (6): 3645 DOI:
10.1021/ acs.est.1c07301 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220323160659.htm

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