Diesel
fuel is widely used throughout our society. It powers trucks that deliver
products to our
communities,
buses that carry us to school and work, agricultural equipment that plants and
harvests
our
food, and backup generators that can provide electricity during emergencies. It
is also used for
many
other applications. Diesel engines have historically been more versatile and
cheaper to run
than
gasoline engines or other sources of power. Unfortunately, the exhaust from
these engines
contains
substances that can pose a risk to human health.
In
1998, the California Environmental Protection Agency’s Office of Environmental
Health Hazard
Assessment
(OEHHA) completed a comprehensive health assessment of diesel exhaust. This
assessment
formed the basis for a decision by the California Air Resources Board (ARB) to
formally
identify
particles in diesel exhaust as a toxic air contaminant that may pose a threat
to human health.
The
American Lung Association of California (ALAC) and its 15 local associations
work to prevent
lung
disease and promote lung health. Since 1904, the
American
Lung Association has been fighting lung
disease
through education, community service, advocacy
and
research.
This
fact sheet by OEHHA and ALAC provides
information
on health hazards associated with diesel
exhaust.
What
is diesel exhaust? What is diesel exhaust? What is diesel exhaust? What is
diesel exhaust?
Diesel
exhaust is produced when an engine burns diesel fuel. It is a complex mixture
of thousands of
gases
and fine particles (commonly known as soot) that contains more than 40 toxic
air
contaminants.
These include many known or suspected cancer-causing substances, such as
benzene,
arsenic
and formaldehyde. It also contains other harmful pollutants, including nitrogen
oxides
(a
component of urban smog).
How
are people exposed to diesel exhaust? How are people exposed to diesel exhaust?
How are people exposed to diesel exhaust? How are people exposed to diesel
exhaust?
Diesel
exhaust particles and gases are suspended in the air, so exposure to this
pollutant occurs
whenever
a person breathes air that contains these substances. The prevalence of
diesel-powered
engines
makes it almost impossible to avoid exposure to diesel exhaust or its
byproducts, regardless
of
whether you live in a rural or urban setting. However, people living and
working in urban and
industrial
areas are more likely to be exposed to this pollutant. Those spending time on
or near roads
and
freeways, truck loading and unloading operations, operating diesel-powered
machinery or
Diesel
exhaust
contains
more
than
40 toxic air
contaminants.
working near diesel
equipment face exposure to higher levels of diesel exhaust and face higher
health
risks.
What
are the health effects of diesel exhaust? What are the health effects of diesel
exhaust? What are the health effects of diesel exhaust? What are the health
effects of diesel exhaust?
As we breathe, the
toxic gases and small particles of diesel exhaust are drawn into the lungs. The
microscopic
particles in diesel exhaust are less than one-fifth the thickness of a human
hair and are
small enough to
penetrate deep into the lungs, where they contribute to a range of health
problems.
Diesel exhaust and
many individual substances contained in
it (including
arsenic, benzene, formaldehyde and nickel)
have the potential
to contribute to mutations in cells that
can lead to cancer.
In fact, long-term exposure to diesel
exhaust particles
poses the highest cancer risk of any toxic
air contaminant
evaluated by OEHHA. ARB estimates that
about 70 percent of
the cancer risk that the average
Californian faces
from breathing toxic air pollutants stems from diesel exhaust particles.
In its comprehensive
assessment of diesel exhaust, OEHHA analyzed more than 30 studies of people
who worked around
diesel equipment, including truck drivers, railroad workers and equipment
operators. The
studies showed these workers were more likely to develop lung cancer than
workers
who were not exposed
to diesel emissions. These studies provide strong evidence that long-term
occupational
exposure to diesel exhaust increases the risk of lung cancer. Using information
from
OEHHA’s assessment,
ARB estimates that diesel-particle levels measured in
could cause 540
“excess” cancers (beyond what would occur if there were no diesel particles in
the
air) in a population
of 1 million people over a 70-year lifetime. Other researchers and scientific
organizations,
including the National Institute for Occupational Safety and Health, have
calculated
cancer risks from
diesel exhaust that are similar to those developed by OEHHA and ARB.
Exposure to diesel
exhaust can have immediate health effects. Diesel exhaust can irritate the
eyes,
nose, throat and
lungs, and it can cause coughs, headaches, light-headedness and nausea. In
studies
with human
volunteers, diesel exhaust particles made people
with allergies more
susceptible to the materials to which they
are allergic, such
as dust and pollen. Exposure to diesel
exhaust also causes
inflammation in the lungs, which may
aggravate chronic
respiratory symptoms and increase the
frequency or
intensity of asthma attacks.
Diesel engines are a
major source of fine-particle pollution.
The elderly and
people with emphysema, asthma, and chronic heart and lung disease are especially
sensitive to
fine-particle pollution. Numerous studies have linked elevated particle levels
in the air to
increased hospital
admissions, emergency room visits, asthma attacks and premature deaths among
those suffering from
respiratory problems. Because children’s lungs and respiratory systems are
still
developing, they are
also more susceptible than healthy adults to fine particles. Exposure to fine
particles is
associated with increased frequency of childhood illnesses and can also reduce
lung
function in
children.
Diesel
exhaust
increases
the risk of
cancer…
…
And it can cause
coughs
and
aggravate
asthma. Diesel exhaust
contributes to smog
and fine-particle
pollution.
Like all
fuel-burning equipment, diesel engines produce nitrogen oxides, a common air pollutant
in
infection
and worsen chronic lung diseases, such as asthma. They also react with other
pollutants in
the
atmosphere to form ozone, a major component of smog.
What is being done to reduce the health risks from diesel exhaust?
What is being done to reduce the health risks from diesel exhaust? What is
being done to reduce the health risks from diesel exhaust? What is being done
to reduce the health risks from diesel exhaust?
Improvements
to diesel fuel and diesel engines have already reduced emissions of some of the
pollutants
associated with diesel exhaust. However, diesel exhaust is still one of the
most widespread
and
toxic substances in
ARB’s
Diesel Risk Reduction Plan, when fully implemented,
will
result in a 75 percent reduction in particle emissions from
diesel
equipment by 2010 (compared to 2000 levels), and an
85
percent reduction by 2020. The plan calls for the use of
cleaner-burning
diesel fuel, retrofitting of existing engines with
particle-trapping
filters, and the use in new diesel engines of
advanced
technologies that produce nearly 90 percent fewer
particle
emissions, as well as the use of alternative fuels.
The use
of other fuels, such as natural gas, propane and
electricity
offer alternatives to diesel fuel. All of them produce fewer polluting
emissions than
current
formulations of diesel fuel. As a result of ARB and local air-quality
regulations, public transit
agencies
throughout
alternative
fuels or retrofitted equipment.
For further information For further information For further
information For further information
Office of Environmental Health Hazard Assessment Office of
Environmental Health Hazard Assessment Office of Environmental Health Hazard
Assessment Office of Environmental Health Hazard Assessment
1001 I
Street,
(916)
324-7572
www.oehha.ca.gov
Air Resources Board Air Resources Board Air Resources Board Air
Resources Board
1001 I
Street,
(800)
363-7664
www.arb.ca.gov
American Lung Association of
(916)
442-4446
For your
local office, call (800) LUNG-USA
www.californialung.org
The energy challenge facing
simple ways you can reduce
demand and cut your energy costs, see OEHHA’s web site at www.oehha.ca.gov/public_info.html.