Emissions Trap Cuts Harmful Diesel Pollution04/11/11
MONDAY, April 11 (HealthDay News) -- A special exhaust filter
for diesel engines cuts emissions of heart-harmful microscopic
particles by 98 percent, which could lead to fewer deaths from
cardiovascular disease, a new study suggests.
The very tiny particles found in diesel engine exhaust are
associated with a slice of the heart disease caused by air
pollution, but "if we use these particle traps on diesel engines,
then we could significantly reduce the harmful effects of air
pollution," said co-senior study author Dr. David E. Newby of the
British Heart Foundation.
The study, funded by grants from heart and lung foundations in
Britain and Sweden, is published in the April 11 online edition of
According to the World Health Organization, air pollution --
including pollution from diesel engines -- is a major contributor
to 800,000 premature deaths each year around the world.
The filtered exhaust, however, appeared to spare the hearts and
lungs of those breathing it, with test subjects experiencing better
blood vessel health and more protection against blood clots than
those exposed to regular diesel exhaust, according to the team led
by Newby, who is also the John Wheatley Chair of Cardiology at the
University of Edinburgh in Scotland.
For the three-way double-blind study, Newby's team randomly
assigned 19 healthy nonsmoking men to breathe filtered air,
unfiltered diesel-engine exhaust and filtered diesel-engine exhaust
-- that is, exhaust after it passed through the particle trap. (To
make the exhaust safe to breathe, 90 percent was shunted away and
the rest mixed with filtered air.)
The men inhaled each gas for one hour and at the same time,
alternated moderate 15-minute bouts of exercise with 15 minutes of
rest. The sessions were at least a week apart.
The researchers found the particle trap removed some 98 percent
of all particles in the diesel exhaust and 99.8 percent of the
smallest and most damaging particles. The trap tested by the
researchers was made by Johnson Matthey, Inc.; however, the
researchers received no funding from the company.
In addition, when compared with filtered air, direct diesel
exhaust reduced the ability of blood vessels to dilate in the six
to eight hours after exposure. Moreover, men breathing filtered air
had a greater release of a compound in the body that dissolves
blood clots than did men breathing unfiltered diesel exhaust.
This compound, called tissue plasminogen activator, is one way
the body helps prevent heart attacks and strokes, the researchers
Another test for blood clotting showed that breathing unfiltered
diesel exhaust increased clotting, compared with both filtered air
and trap-filtered diesel exhaust. In fact, there was no difference
in clotting ability between those who inhaled filtered diesel
exhaust and filtered air, the researchers found.
Martin Lassen, director of business development at Johnson
Matthey, Inc., which makes the diesel particle trap, said the
particle trap for trucks would cost an additional $5,000 to $7,000
per vehicle. For cars, the cost would be under $2,000.
"In addition, the filter has no effect on fuel economy," Lassen added.
Dr. Robert D. Brook, an associate professor of medicine in the
cardiovascular medicine division at the University of Michigan and
co-author of an accompanying journal editorial, said that "these
findings strongly support the concept that reducing the particulate
pollution associated with diesel, and likely other combustion
sources of air pollution, can lead to substantial improvements in
In addition, the results also support the 2007 regulations for
diesel particle traps in U.S. vehicles and also the retro-fitting
of the existing fleet to protect the public health, Brook said.
Starting with the 2007 model year, pollution from trucks and buses
had to be reduced by more than 90 percent, according to the U.S.
Environmental Protection Agency.
"The findings also suggest that it is principally the particles, rather than the gaseous pollutants, involved in triggering adverse cardiovascular health responses to brief diesel air pollution," he added.
"Even brief exposure to particulate matter air pollution can rapidly trigger -- within hours -- adverse cardiovascular health responses capable or promoting an acute event such as heart attack or stroke in susceptible people. Available technology of particle traps appear capable of substantially reducing this risk," Brook said.
For more information on air pollution, visit the
U.S. National Library of Medicine.
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