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UNION OF CONCERNED SCIENTISTS
Citizens and Scientists for Environmental Solutions
www.ucsusa.org
Clean Vehicles
B Ma it this to a frie nd
Diesel Pollution
Diesel Engines and Public Health
Diesel engines power most of the -
nationls trucks, buses, trains, W ~~~i.~1:.f~. +}:~..~-~>
ships, and off-road machinery.
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But each diesel engine can in clean vehicles
Diesel Cars and the Environment
produce tons of air pollutants over Greenersch09lbuscampaia~
its lifetime. With mounting Dirty diesel sch~tol b_uses.
evidence that diesel exhaust
poses major health hazards, reducing diesel pollution has
become a public priority.
Diesel Pollution
Most diesel engines
used today power heavy
vehicles such as freight
trucks, buses,
construction and
agricultural equipment, Pasen.r Non road
trains, and barges. Veb~Es DIe!e I
Diesel passenger 5(1(. Equ Iprnent
vehicles make up only I'""
a small share of the
current US market, but Other
automakers are
working to reintroduce 6%
diesel engines into
sport utility vehicles, Transportation Sources of
pickups, and passenger Nitrogen Oxide Emissions
cars. While diesel cars Transportation = 49% US Total
are more efficient than
their gasoline
counterparts,
regulations permit
them to emit far more
pollutants. Such a
tradeoff between
efficiency and clean air
is both unwise and
unnecessary.
http://www.ucsusa.orglclean_vehicleslbig_rig_ cleanup/ diesel-engines-and-public-health.ht... 4/25/2006
Diesel Engines and Public Health Page 2 of4
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Diesel engines emit
large quantities of
particulate matter
(called PM) and
nitrogen oxides (NOx)'
the latter a precursor
to particulates and
smog. Collectively,
. diesel-powered
vehicles account for
nearly half of all
nitrogen oxides and
more than two-thirds
of all particulates from
US transportation.
Transportation Sources of
Particulate Emissions
Health Impacts Transportation = 2% US Total
Particulates irritate the eyes and nose and aggravate respiratory
problems, including asthma, which afflicts 13 million Americans.
Very small particles, called fine particulates, have also been
directly associated with an increased risk of premature death.
One recent landmark study found that the risk of premature
death in areas with high levels of fine particulates was 26
percent greater than in areas with lower levels. Researchers
estimate that, nationwide, tens of thousands of people die
prematurely each year as a result of particulate pollution. Diesel
engines contribute to the problem by releasing particulates
directly into the air and by emitting nitrogen oxides and sulfur
oxides, which transform into "secondary" particulates in the
atmosphere.
Diesel-related emissions of nitrogen oxides also contribute to
ozone, the major ingredient in the smog engulfing major cities.
High up in the stratosphere, ozone shields the earth from
harmful ultraviolet rays. But at ground level, ozone--formed
when nitrogen oxides and hydrocarbon emissions combine in
the presence of sunlight--irritates the respiratory system,
causing coughing, choking, and reduced lung capacity. Urban
ozone pollution has been linked to increased hospital admissions
for respiratory problems such as asthma, even at levels below
the current standard. Ozone presents hazards for healthy adults
as well: one study of nonsmoking adults in the ozone-heavy Los
Angeles area found that their breathing capacity was reduced as
much as that of pack-a-day smokers.
In addition to contributing to mainstream air pollution problems,
public health agencies consider diesel exhaust a potential
human carcinogen. Exposure to high levels of diesel exhaust
causes lung tumors in rats, and studies of humans routinely
exposed to diesel fumes indicate a greater risk of lung cancer.
For example, occupational health studies of railroad, dock,
http://www.ucsusa.org/clean_vehicleslbig_rig_ cleanup/ diesel-engines-and -public-health.ht... 4/25/2006
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