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 Exposure to so-called PM2.5 - tiny particles of dust, dirt, soot,
and smoke - has long been linked to an increased risk of
cardiovascular diseases, researchers note in JAMA Internal Medicine.
But less is known about whether portable air filters might help
reduce this risk.
The current study involved 40 nonsmokers living in low-income
housing for seniors in Detroit, Michigan. The residence was located
near major roadways and industrial facilities that release fine
particulate matter into the air.
Residents' blood pressure was measured after they used three
different types of portable air filters, each for three days at a
time: a low-efficiency air filter; a high efficiency particulate
arrestance (HEPA) filter; and a sham filter that didn't clean the
air at all.
Compared to when they used the sham filter, the seniors' average
exposure to PM2.5 indoors was 31 percent lower with the
low-efficiency filter and 53 percent lower with the HEPA filter.
And with use of the air filters, blood pressure levels in people
with hypertension improved by an amount similar to what might be
achieved with lifestyle changes like increased exercise or reduced
salt consumption, said lead study author Masako Morishita of
Michigan State University in East Lansing.
"A simple intervention using inexpensive indoor air filtration units
can help to lower both PM2.5 exposures and blood pressure levels,"
Morishita said by email. "Since hypertension is the leading risk
factor for death worldwide, we believe much larger trials are
warranted to test whether air filtration units can play an important
role in helping to prevent cardiovascular diseases worldwide."
The World Health Organization attributes four million deaths a year
to fine particulate matter exposure. Its guidelines recommend
against average exposure above 10 micrograms per cubic meter of air
(ug/m3), the authors note. In this study, the average exposure was
15.5 ug/m3 without air filtration, 10.9 ug/m3 with low-efficiency
filtration, and 7.4 ug/m3 with HEPA filters.
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In adults, blood pressure readings of 120/80 mmHg (millimeters of
mercury) or lower are considered healthy. Study participants'
average blood pressure was 133/82 mmHg with sham filters, 129.5/80.2
with low-efficiency air filters and 130.7/81.9 with HEPA filters.
One limitation of the study is that it was too small to detect
meaningful differences in blood pressure based on the type of air
filters used, the authors note. The study also didn't track people
to see if they actually developed or died from cardiovascular
diseases.
Even so, air filters may be a simple way to reduce the negative
health effects of exposure to fine particulate matter, said Shohreh
Farzan, an environmental health researcher at the Keck School of
Medicine at the University of Southern California in Los Angeles who
wasn't involved in the study.
Relatively small reductions in blood pressure can improve
cardiovascular health, Farzan said by email.
Consumers should look for HEPA filters that also have activated
carbon filters and are certified by the Association of Home
Appliance Manufacturers (AHAM), said Kai-Jen Chuang, a public health
researcher at Taipei Medical University in Taiwan who wasn't
involved in the study.
People also need to measure the size of the room where filters will
be used to make sure the filter is powerful enough to clean the
amount of air in the space, Chuang said by email.
SOURCE: http://bit.ly/2COPAjr JAMA Internal Medicine, online
September 10, 2018.
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