• Pacific Northwest wildfires alter air po

    From ScienceDaily@1:317/3 to All on Tue Apr 19 22:30:44 2022
    Pacific Northwest wildfires alter air pollution patterns across North
    America
    Increase in August pollution could have far-reaching health implications


    Date:
    April 19, 2022
    Source:
    National Center for Atmospheric Research/University Corporation
    for Atmospheric Research
    Summary:
    Increasingly large and intense wildfires in the Pacific Northwest
    are altering the seasonal pattern of air pollution and causing
    a spike in unhealthy pollutants in August, according to new
    research. The smoke is undermining clean air gains, posing potential
    risks to the health of millions of people, according to the study.



    FULL STORY ========================================================================== Increasingly large and intense wildfires in the Pacific Northwest are
    altering the seasonal pattern of air pollution and causing a spike
    in unhealthy pollutants in August, new research finds. The smoke is
    undermining clean air gains, posing potential risks to the health of
    millions of people, according to the study.


    ==========================================================================
    The research, led by scientists at the National Center for Atmospheric
    Research (NCAR), found that levels of carbon monoxide -- a gas that
    indicates the presence of other air pollutants -- have increased sharply
    as wildfires spread in August. Carbon monoxide levels are normally lower
    in the summer because of chemical reactions in the atmosphere related
    to changes in sunlight, and the finding that their levels have jumped
    indicates the extent of the smoke's impacts.

    "Wildfire emissions have increased so substantially that they're
    changing the annual pattern of air quality across North America," said
    NCAR scientist Rebecca Buchholz, the lead author. "It's quite clear that
    there is a new peak of air pollution in August that didn't used to exist." Although carbon monoxide generally is not a significant health concern outdoors, the gas indicates the presence of more harmful pollutants,
    including aerosols (airborne particulates) and ground-level ozone that
    tends to form on hot summer days.

    The research team used satellite-based observations of atmospheric
    chemistry and global inventories of fires to track wildfire emissions
    during most of the past two decades, as well as computer modeling to
    analyze the potential impacts of the smoke. They focused on three North American regions: the Pacific Northwest, the central United States,
    and the Northeast.

    Buchholz said the findings were particularly striking because carbon
    monoxide levels have been otherwise decreasing, both globally and across
    North America, due to improvements in pollution-control technologies.



    ==========================================================================
    The study was published this week in Nature Communications.The research
    was funded in part by the U.S. National Science Foundation, NCAR's
    sponsor. The paper was co-authored by researchers from the University
    of Colorado, Boulder; Columbia University; NASA; Tsinghua University;
    and Colorado State University.

    Increasing impacts on air pollution Wildfires have been increasing in the Pacific Northwest and other regions of North America, due to a combination
    of climate change, increased development, and land use policies. The fires
    are becoming a larger factor in air pollution, especially as emissions
    from human activities are diminishing because of more efficient combustion processes in motor vehicles and industrial facilities.

    To analyze the impacts of fires, Buchholz and her collaborators
    used data from two instruments on the NASA Terra satellite: MOPITT (Measurements of Pollution in the Troposphere), which has tracked
    carbon monoxide continually since 2002; and MODIS (Moderate Resolution
    Imaging Spectrometer), which detects fires and provides information
    on aerosols. They also studied four inventories of wildfire emissions,
    which rely on MODIS data.

    The scientists focused on the period from 2002, the beginning of a
    consistent and long-term record of MOPPIT data, to 2018, the last year
    for which complete observations were available at the time when they
    began their study.



    ==========================================================================
    The results showed an increase in carbon monoxide levels across North
    America in August, which corresponded with the peak burning season of
    the Pacific Northwest. The trend was especially pronounced from 2012 to
    2018, when the Pacific Northwest fire season became much more active,
    according to the emissions inventories. Data from the MODIS instrument
    revealed that aerosols also showed an upward trend in August.

    To determine whether the higher pollution levels were caused by the fires,
    the scientists eliminated other potential emission sources. They found
    that carbon monoxide levels upwind of the Pacific Northwest, over the
    Pacific Ocean, were much lower in August -- a sign that the pollution
    was not blowing in from Asia.

    They also found that fire season in the central U.S. and the Northeast
    did not coincide with the August increase in pollution, which meant
    that local fires in those regions were not responsible. In addition,
    they studied a pair of fossil fuel emission inventories, which showed
    that carbon monoxide emissions from human activities did not increase
    in any of the three study regions from 2012 to 2018.

    "Multiple lines of evidence point to the worsening wildfires in the
    Pacific Northwest as the cause of degraded air quality," Buchholz
    said. "It's particularly unfortunate that these fires are undermining the
    gains that society has made in reducing pollution overall." Risks to
    human health The findings have implications for human health because
    wildfire smoke has been linked to significant respiratory problems, and it
    may also affect the cardiovascular system and worsen pregnancy outcomes.

    Buchholz and her co-authors used an NCAR-based computer model, the
    Community Atmosphere Model with a chemistry component, to simulate
    the movement of emissions from the Pacific Northwest fires and their
    impact on carbon monoxide, ozone, and fine particulate matter. They
    ran the simulations on the Cheyenne supercomputer at the NCAR-Wyoming Supercomputing Center. The results showed the pollutants could affect
    more than 130 million people, including about 34 million in the
    Pacific Northwest, 23 million in the Central U.S., and 72 million in
    the Northeast.

    Although the study did not delve deeply into the health implications of
    the emissions, the authors looked at respiratory death rates in Colorado
    for the month of August from 2002 to 2011, compared with the same month
    in 2012 to 2018. They chose Colorado, located in the central U.S. region
    of the study, because respiratory death rates in the state were readily obtainable.

    They found that Colorado respiratory deaths in August increased
    significantly during the 2012-2018 period, when fires in the Pacific
    Northwest -- but not in Colorado -- produced more emissions in August.

    "It's clear that more research is needed into the health implications of
    all this smoke," Buchholz said. "We may already be seeing the consequences
    of these fires on the health of residents who live hundreds or even
    thousands of miles downwind."

    ========================================================================== Story Source: Materials provided by National_Center_for_Atmospheric_Research/University Corporation_for_Atmospheric_Research. Original written by David
    Hosansky. Note: Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Rebecca R. Buchholz, Mijeong Park, Helen M. Worden, Wenfu Tang,
    David P.

    Edwards, Benjamin Gaubert, Merritt N. Deeter, Thomas Sullivan,
    Muye Ru, Mian Chin, Robert C. Levy, Bo Zheng, Sheryl Magzamen. New
    seasonal pattern of pollution emerges from changing North American
    wildfires.

    Nature Communications, 2022; 13 (1) DOI: 10.1038/s41467-022-29623-8 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/04/220419091846.htm

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