N95 respirators could offer robust protection from wildfire smoke

Date:
September 27, 2021
Source:
American Geophysical Union
Summary:
N95 respirators offer the best protection against wildfire smoke and
other types of air pollution, performing better than synthetic,
cotton and surgical masks. N95s were so effective in the lab
experiments that the researchers estimate their widespread use could
reduce hospital visits attributable to wildfire smoke by 22% to 39%.



FULL STORY ==========================================================================
N95 respirators offer the best protection against wildfire smoke and
other types of air pollution, performing better than synthetic, cotton
and surgical masks.


========================================================================== Researchers performed lab experiments to investigate the ability of
different face masks and respirators to filter out particles in a range
of sizes found in smoke and air pollution. They placed the different
mask materials over a pipe that "breathes" in air and particles inside
a plastic box.

N95s were so effective in the lab experiments that the researchers
estimate their widespread use could reduce hospital visits attributable
to wildfire smoke by 22% to 39%. The study's findings can provide evidence-based recommendations to help people protect themselves during wildfire season.

The new study was published in GeoHealth, AGU's journal investigating
the intersection of human and planetary health for a sustainable future.

Climate change has made wildfires more frequent and intense in the
Western U.S., and the resulting smoke exposure is taking a toll on
people's health.

Wildfire smoke contains tiny particles smaller than 2.5 microns in
diameter (PM2.5) -- about the size of a single bacterium -- that enter
the lungs and are linked to multiple health problems, including a higher
risk of asthma, respiratory infections and chronic obstructive pulmonary disease (COPD).

Face coverings have become second nature to many people during the
coronavirus pandemic, making some wonder if masks and respirators could
also protect against smoke and pollution. By definition, respirators are tight-fitting protective equipment that seal around the nose and mouth to filter the air coming in and out. Surgical-style face masks are designed
to capture the droplets and particles produced by the wearer to prevent
the spread of disease.



========================================================================== "People were asking, should we keep them on in the summer when the fire
season starts?" said Jack Kodros, an atmospheric scientist at Colorado
State University and lead author on the new study. "There weren't a lot
of guidelines on what sort of masks would be helpful for wildfire smoke." Kodros and his team measured how well N95 respirators and synthetic,
cotton and surgical masks each filter out the sizes of particles found
in air pollution.

Then they calculated how much each face covering would reduce exposure to pollution by considering their ability to filter the particles, and how
much air the masks are likely to leak when attached to a person's face.

They found that N95s offer the best protection against wildfire smoke,
reducing a person's exposure by a factor of 16. Synthetic and cotton
masks do a poor job of filtering out the particle sizes found in
wildfire smoke, and only reduced exposure by a factor of 2.2 and 1.4, respectively. Surgical masks filter more than 90% of the particles but
previous research has shown they let about 50% of the air leak around
the mask, making them only about as effective as the synthetic and
cotton options.

N95s also worked best against larger dust particles and urban air
pollution, which contains particles from car exhaust that are even
smaller than particles from wildfire smoke.

Reducing Hospitalizations from Wildfire Smoke In the second part of their study, the researchers estimated the benefits of mask wearing across an
entire population. They developed a model that took into account the
percentage of people likely to wear masks and how consistently they
would wear them. They applied the model to the 2012 Washington state
fire season to see if mask wearing would have changed the number of hospitalizations due to respiratory problems.



==========================================================================
The model suggested that N95s would have prevented about 30% of the
hospital visits from wildfire smoke. Surgical masks and synthetic masks
would have reduced visits by about 17% and 13%, respectively, while
cotton masks would have caused only a 6% reduction.

Kodros emphasizes that these mask recommendations are specific to air
pollution and do not apply to the coronavirus. "For COVID-19, you're
wearing a mask to protect yourself and also to reduce your own emitted droplets," he said. Fabric masks have been shown to be effective for
public health during the current crisis and the Centers for Disease
Control and Prevention (CDC) recommends the use of masks with two or
more layers of fabric that fit snugly over the nose and mouth.

Stephanie Holm, a pediatrician, environmental epidemiologist and
co-director of the Western States Pediatric Environmental Health
Specialty Unit at the University of California, San Francisco, says that currently there is a lot of interest -- but also a lot of confusion --
about how well different mask materials filter out particles. "I think
this particular study fills a nice gap in terms of thinking about how we translate that kind of filtration data into real levels of protection,
and real differences in health effects that we could see in a population,"
she said.

Holm was not involved in the study, but she frequently advises families
on how to protect themselves from wildfire smoke and is excited to
incorporate this information into her recommendations.

========================================================================== Story Source: Materials provided by American_Geophysical_Union. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. John K. Kodros, Katelyn O'Dell, Jonathan M. Samet, Christian
L'Orange,
Jeffrey R. Pierce, John Volckens. Quantifying the Health Benefits
of Face Masks and Respirators to Mitigate Exposure to Severe
Air Pollution.

GeoHealth, 2021; 5 (9) DOI: 10.1029/2021GH000482 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/09/210927143654.htm

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