United States             Air and Radiation        EPA420-F-03-010
                  Environmental Protection                        April 2003

                  Office of Transportation and Air Quality
&EPA       Regulatory
                  Public Health and Environmental
                  Benefits of EPA's Proposed
                  Program for Low-Emission  Nonroad
                  Diesel Engines and Fuel
                  The U. S. Environmental Protection Agency (EPA) has proposed
                  emission standards for nonroad diesel engines and fuel. This fact
                  sheet summarizes the estimated benefits of the proposal to public
                  health and the environment.
                  EPA has proposed a comprehensive national program to reduce emis-
                  sions from future nonroad diesel engines and fuel. The proposed exhaust
                  emission standards would apply to new diesel engines used in most kinds
                  of construction, agricultural, industrial, and airport equipment. To meet
                  the proposed emission standards, engine manufacturers will produce new
                  engines with advanced systems for controlling emissions. These emission
                  control devices would be damaged by sulfur, so the proposal also aims to
                  dramatically reduce the level of sulfur in nonroad diesel fuel used by this
                  equipment, and the fuel used by locomotive and marine engines.
                  Air Quality Impact of Nonroad Diesel Engines
                  EPA estimates that the nonroad engines covered by this proposal contrib-
                  ute over 44 percent of diesel particulate matter (PM) emissions nationally
                  and over 12 percent of nitrogen oxides (NOx) emissions from mobile
                  sources. In some urban areas the contribution is greater. Without this
                  proposed control program, these percentages would continue to increase.

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               Air quality problems are widespread in the United States. Hundreds of
               millions of Americans currently live in counties with unhealthy air. This
               proposal would help reduce harmful pollution. For more information
               about air quality where you live, see the web page: http://www.epa.gov/
               air/data/geosel .html.
               Human Health and Environmental Impacts of These
               Air Pollutants
               The engines covered by the proposed standards contribute to formation
               of fine particles and ozone. In addition, these engines emit Mobile Source
               Air Toxics such as diesel exhaust, benzene, 1,3-butadiene, formaldehyde,
               acetaldehyde, acrolein, and other substances.

Particulate    Particulate matter represents a broad class of chemically and physically
Matter        diverse substances. "Fine particulate matter" includes liquid and solid
               particles with a diameter of 2.5 microns or less (also known as PM25).
               Fine particles are produced any time fuels such as coal, oil, diesel fuel,
               gasoline, or wood are burned. Power plants, various industries, cars and
               trucks, buses, nonroad diesel and gasoline engines, wood stoves, forest
               fires, agricultural burning, and marine engines are all sources of fine
               particles. Fine particles are directly emitted or formed in the atmosphere
               from precursors such as NOx and Sulfur Oxides.

               Particulate matter has been linked to a range of serious respiratory and
               cardiac health problems, including premature mortality, and hospital
               admissions or emergency room visits for lung and heart diseases. Particles
               can aggravate lung diseases such as asthma and bronchitis, causing
               increased medication use, doctors visits, and restriction in activity or
               missed days of work and school. Particles can aggravate heart diseases
               such as congestive heart failure and coronary artery disease. Particles
               have also been associated with cardiac arrhythmias (heartbeat irregulari-
               ties) and heart attacks. There is emerging evidence suggesting increased
               blood markers of inflammation (indicators of cardiac risk) are associated
               with ambient PM. These effects have been associated with both short-
               term (usually  over a 24-hour period, but possibly as short as 1-hour) and
               long-term exposures (years).

               Groups of people considered to be the most sensitive to particles include
               people with heart or lung diseases; older adults - possibly because they
               are more likely to have undiagnosed heart or lung diseases; and children -
               whose bodies are still developing and who are more likely to be active
               outdoors and to have asthma.

Diesel        In addition to its contribution to ambient PM inventories, diesel exhaust is
Exhaust      of specific concern because it has been judged to pose a lung cancer
               hazard for humans as well as a hazard from noncancer respiratory effects.
               In EPA's final "Health Assessment Document for Diesel Engine Exhaust,"
               which received extensive scientific peer review, EPA classified diesel
               exhaust as likely to be carcinogenic to humans by inhalation at environ-
               mental exposures. Several other agencies have made similar classifica-
               tions, including the National Institute for Occupational Safety and Health,
               the International Agency for Research on Cancer, the World Health
               Organization, California EPA, and the U.S. Department of Health and
               Human Services. EPA also recently assessed air toxic emissions and their
               associated risk and concluded that diesel exhaust ranks with other sub-
               stances that the national-scale assessment suggests pose the greatest
               relative risk.

Air Toxics    Emissions from the engines covered by this proposal also contain several
               Mobile Source Air Toxics, including benzene,  1,3-butadiene, formalde-
               hyde, acetaldehyde, and acrolein, which cause a variety of health-related
               problems. Users of these engines may experience high levels of personal
               exposure to these substances.

Ozone        Ground-level ozone, the main ingredient in smog, is formed by complex
               chemical reactions of NOx and volatile organic compounds in the pres-
               ence of heat and sunlight. Ozone forms readily in the lower atmosphere,
               usually during hot summer weather. Volatile organic compounds come
               from some natural sources (such as vegetation), but mostly come from
               mobile sources (such as nonroad engines, cars, and trucks), chemical
               plants, refineries, factories, consumer and commercial products, and other
               industrial sources. NOx emissions come largely from motor vehicles,
               nonroad equipment, power plants, and other sources of combustion.

               Ozone can irritate the respiratory system, causing coughing, throat
               irritation, and/or uncomfortable sensations in the chest. Ozone can reduce
               lung function and make it more difficult to breathe deeply; breathing may
               become more rapid and shallow than normal, thereby limiting a person's
               normal activity. Ozone can also aggravate asthma and other respiratory
               diseases, leading to more asthma attacks, use of additional medication,
               more severe symptoms that require a doctor's attention, more visits to the
               emergency room, and increased hospitalizations. In addition, ozone can
               inflame and damage the lining of the lungs, which may lead to permanent

               changes in lung tissue, irreversible reductions in lung function if the
               inflammation occurs repeatedly over a long time period and a lower
               quality of life. People who are particularly susceptible to the effects of
               ozone include healthy children and adults who are active outdoors,
               people with respiratory disease, such as asthma, and people with unusual
               sensitivity to ozone.

Visibility      Visibility is important because it directly affects people's enjoyment of
               daily activities in all parts of the country. Visibility is highly valued in
               significant natural areas such as national parks and wilderness areas
               because of the special emphasis given to protecting these lands now and
               for future generations. Fine particles from sources such as power plants
               using fossil fuels, motor vehicles, and nonroad engines are the major
               cause of reduced visibility.

Other         Emissions from nonroad diesel engines contribute to other effects includ-
Environmental   ing ecosystem damage, acid deposition, odor, production of organic
Effects        matter in water bodies that leads to nuisance algal blooms,  crop damage,
               soiling, and material damage.
               Air Quality Benefits of This Proposal
               When fully implemented, this proposal would reduce nonroad diesel
               PM25 and NOx emissions by over 90 percent. It will reduce NOx emis-
               sions nationwide by over 825,000 tons annually and PM emissions by
               over 125,000 tons. It will also virtually eliminate SOx emissions from
               nonroad diesel engines, which amount to nearly 300,000 tons per year,
               and reduce air toxic emissions by about 30 percent.

               These dramatic emission reductions are a critical part of the effort by
               federal, state, local, and tribal governments to reduce the health related
               impacts of air pollution.  The reductions will help areas to reach attain-
               ment of the National Ambient Air Quality Standard (NAAQS) for PM
               and ozone. These reductions are also needed to help our national parks
               and wilderness areas, which have particular needs for reducing haze to
               protect scenic vistas.

               These controls will help reduce ambient concentrations of fine PM,
               ozone, and air toxics. EPA modeling projections show that this proposal
               will substantially reduce exposures nationwide, including improvements
               that allow several areas to attain air quality standards. Specifically, EPA

projects that the number of people living in counties with PM2 5 levels
above the NAAQS in 2020 would be reduced from 66 million to 60
million. That represents a reduction of 9 percent in exposed population
and 15 percent in the number of counties. In 2030, there would be a
reduction from 85 million people to 71 million exposed to high PM
levels, which represents an even greater improvement than projected for
2020 because of the increased turnover of nonroad equipment. This
corresponds to a 16 percent reduction in exposed population and a 21
percent reduction in the number of counties. In addition, those areas that
continue to have high PM levels would be closer to meeting air quality
standards and areas that already meet air quality standards for PM would
be better able to remain in attainment. The proposed program would also
reduce ozone and toxics nationally.
Health Benefits of the New Standards
The PM air quality improvements expected from this proposal produce
major benefits to human health and welfare. By the year 2030, this pro-
posed rule would annually prevent all of the following:

  •  9,600 premature deaths
  •  16,000 nonfatal heart attacks
  •  5,700 cases of chronic bronchiti s
  •  8,300 hospital admissions
  •  14,000 acute bronchitis attacks in children
  •  260,000 respiratory symptoms in children (related to PM)
  •  nearly 1 million lost work days among adults
  •  6 million days where adults have to restrict their activities due to
     respiratory symptoms

In monetary terms, EPA estimates annual benefits in 2030 to be about
$81 billion when the program is fully phased in. The proposed program
will reduce personal exposure for people who operate or are otherwise
close to these engines. There are additional health and welfare benefits,
such as those related to reduced levels of ozone, carbon monoxide, and
air toxics, that are not included in the above estimate.

Where Can I Get More Information?
For more information on the environmental and health impacts of these
proposed emission standards, see the Draft Regulatory Impact Analysis
(especially Chapter 2—Air Quality, Health, and Welfare Effects). You can
access that document and others related to the rulemaking on EPA's Web
site at:


You can also contact us at:

    U.S. Environmental Protection Agency
    Assessment and Standards Division
    2000 Traverwood Drive
    Ann Arbor, MI 48105
    Voice-mail: (734)214-4636
    E-mail: asdinfo@epa.gov