What You  Should  Know  About  Reducing
Diesel  Exhaust  from  School  Buses
         buses provide our nation's children with
     safe, convenient transportation. Diesel exhaust
     from school buses, however, poses a health
risk, particularly to children. Diesel exhaust contains
small particles as well as smog-forming and toxic air
pollutants. Exposure to diesel exhaust can cause
lung damage and respiratory problems and can
exacerbate asthma and existing allergies.  Buses that
idle outside schools can pollute the air inside the
school building as well as outdoors.  Fortunately,
there are several steps that schools can take to
reduce diesel exhaust from school buses.

Recommended Actions
to Reduce Diesel Pollution
Clean School Bus USA encourages school districts
to reduce the health risks associated with  exposure
to diesel exhaust by:
 Deducing school bus idling time and reinforcing
   smart driving practices, such as following at least
   three car lengths behind any vehicle with visible
   exhaust or a noticeable odor.
 retrofitting current school bus fleets with new
   technologies and introducing cleaner fuels.
 replacing the oldest buses with new ones that
   meet stringent pollution control standards.
How Are Children Affected?
Air pollution from diesel vehicles has health
implications for everyone, but children are
more susceptible to this pollution because
they breathe at a faster rate than adults.
Children's lungs are still developing, and
children are more likely to play actively
outdoors. More than 24 million children in
the United States ride a bus to and from
school every day.
Help Clear the Air with
Clean School Bus USA
Clean School Bus USA is an initiative sponsored
by the U.S. Environmental Protection Agency
(EPA) to help communities reduce pollution from
school buses. It's a partnership of educators,
industry, businesses, school officials, school bus
fleet and transportation managers, state and local
governments, public health officials, and other
community leaders who are committed to
protecting children's health and modernizing
America's school bus fleet.

Clean  School Bus  USA
Case Studies
     Communities across the country are
     developing effective local
 partnerships to reduce air pollution from
 diesel school buses. School children in
 these areas reap immediate air quality
 benefits from effective anti-idling policies,
 buses that run on cleaner fuels, and
 buses retrofitted with state-of-the-art
 emission reduction technologies.

 Portland, Maine
 In the last five years, the Portland school
 district has replaced 90 percent of its
 school bus fleet with newer, cleaner
 buses. This pioneering effort is part of a
 multi-faceted statewide campaign to
 reduce emissions from diesel school
 buses. The campaign—a partnership
 between the Portland School
 Transportation Department, the Maine
 Departments of Education and
 Environmental Protection, the Asthma
 Regional Council, and the U.S.
 Environmental Protection Agency-
 focuses on: anti-idling and fuel
 conservation; aggressive investments in
 newer, cleaner buses; and route
 management to assign the cleanest buses
 to the longest routes.

 State of Washington
 With support from Washington's
 legislature, schools throughout the state
 will retrofit bus fleets, reducing  toxic
ere are some specific actions school districts can take
to achieve these goals:
Implement Anti-idling and
Smart Driving Practices
  • Train school bus drivers to turn off their buses as
    soon as they arrive at loading or unloading areas and
    to refrain from restarting their buses until they are
    ready to depart.
  • Establish a program to recognize drivers who
    successfully reduce idling.
  • Consider changing circuit configurations if necessary
    to power flashing lights with the battery.
  • Limit idling time during early morning warm-up to
    what is recommended by the manufacturer (generally
    3 to 5 minutes). In colder climates,  block heaters can
    help warm the engine of older vehicles to avoid
    starting difficulties and shorten warm-up time. Newer
    buses are designed to start easily at all temperatures
    without idling.
  • In the winter, provide a space inside the school where
    bus drivers who arrive early can wait.
  • Follow the anti-idling laws and guidelines that many
    states have in place. Post signs as  reminders.
  • Revise bus schedules and operational  logistics to
    minimize school bus caravanning.
  • Assign cleanest buses to the longest trips. Inform
    drivers that following other diesel vehicles too closely
    can contribute to higher concentrations of diesel
    exhaust inside and outside  the bus.
   Jdling wastes fuel and money.
    I ypical school buses burn
    approximately one-half gallon of
    diesel fuel for each hour of idling.
    I he less school buses idle, the more
    money school districts can save.
                    continued on next page

Work Closely with Fleet Managers
and Bus Drivers to Reinforce
  •  Make sure both fleet managers and bus drivers
     understand the potential health risks from
     breathing diesel exhaust and the benefits of not
     idling or caravanning.
  •  Highlight the economic benefit of reduced fuel
     consumption as a result of less idling.  For exam-
     ple, if a fleet operates  50 buses and each bus
     reduces its idling time  by 30 minutes per day, at
     $1 per gallon of diesel fuel, the fleet would save
     $2,250 per school year in fuel costs.
  •  Maintain engines properly.

Work Closely with Fleet Managers
to Retrofit Buses  with
Pollution Controls
Oxidation catalysts and particulate matter filters are
two retrofit technologies that can help reduce diesel
particulate matter.  Both devices are housed  in the
exhaust system where they  break down the pollutants
in the exhaust.
Oxidation Catalysts
Diesel oxidation  catalysts are widely available and
commonly used retrofit technologies. They are relative-
ly simple, low cost devices that can be installed in
almost all buses and require very little maintenance.
Diesel oxidation  catalysts can be used with regular
diesel fuel. Diesel oxidation catalysts typically cost
between $1,000 and $2,000 and reduce particulate
matter emissions by 20 to 30 percent. Reductions
may be even higher if used together with ultra-low
sulfur diesel fuel.
Particulate Matter Filters
Diesel particulate matter filters provide even  greater
particulate matter reductions.  Filters are a more com-
plex technology than catalysts and generally are most
appropriate for 1995 and newer buses. Filters typically
cost between $5,000 and $10,000 and require the
use of ultra-low sulfur diesel fuel. The combination of
ultra-low sulfur diesel and particulate matter filter tech-
nology reduces particulate matter emissions by 60 to
90 percent.
Case Studies
  diesel emissions by 50 to 90 percent. This
  program, named the Washington State
  Clean School Bus Program, will affect
  approximately 5,000 of more than 9,000
  school buses throughout the state by
  2008, making it the largest state-funded
  voluntary school bus retrofit program in
  the country. The Puget Sound Clean Air
  Agency, in partnership with several state
  and local agencies, conducted pilot
  programs with U.S. EPA grants during the
  past two years to pave the way for rapid
  deployment of retrofitted buses. Retrofits
  for buses will involve either installation of
  particulate matter filters or oxidation
  catalysts on school bus exhaust systems,
  depending on the age of the bus and the
  regional availability of ultra-low sulfur
  diesel fuel. To maximize program benefits,
  older school buses that pollute the most
  will be the first to receive retrofits.

  Ardmore, Pennsylvania
  Nearly 70 percent of the Lower Merion
  School District's fleet of 107 buses
  operate on compressed natural gas
  (CNG), providing noise relief and clean
  air benefits to the residential
  neighborhoods where these buses
  operate. To build local fast-fill CNG
  refueling stations and offset the upfront
  costs of the new buses, the district
  received several grants from community,
  state, and federal partners. Lower
  Merion's CNG fleet has now logged
  nearly 5 million miles.

Work Closely with
Fleet Managers to
Purchase Cleaner Fuels
There are a number of alternatives to conventional
diesel fuel that can help reduce particulate matter
emissions from today's school bus fleet. Most of these
fuels can be used with little or no modification to the
bus or its engine:
  •  Alternative fuels such as compressed natural
     gas offer outstanding environmental benefits for
     buses designed to run on such  fuels.

  •  Biodiesel is a fuel that contains some
     domestically produced, renewable components.
     Blends of biodiesel (B20) can be used in
     unmodified diesel engines,  but pure biodiesel
     (B100) may require certain engine modifications.
     Pure biodiesel may not be suitable for cold

  •  Emulsified diesel fuel  is a blended mixture of
     diesel fuel, water, and other additives.
     Emulsified diesel can  be used in any diesel
     engine to reduce emissions of particulate matter
     as well as nitrogen oxides.
  •  Ultra-low sulfur diesel fuel is diesel fuel with an
     extremely low sulfur content (15 or less parts
     per million). The low sulfur  levels enable
     particulate matter filters to  perform most
     efficiently. Ultra-low sulfur diesel will be required
     nationwide for use in all highway diesel  vehicles
     beginning in 2006 and is currently available in
     some parts of the country.
Work Closely with
Fleet Managers to
Replace the  Oldest Buses
with New Ones
  •  About one third of U.S. school buses were
     manufactured  before 1990 and are not
     equipped with modern pollution controls and
     the latest safety features. These buses are
     excellent candidates for accelerated
  •  By 2007, EPA will require that new buses rolling
     off the assembly lines be 95 percent cleaner
     than today's models. Because some buses
     might meet EPA standards ahead of schedule,
     ask the manufacturer before purchasing a new
     bus to see if you can acquire one that meets
     these standards.
  •  Both diesel and compressed natural gas tech-
     nologies offer very clean replacement options.
                           For more information about Clean School Bus USA:


                               Leave a voice message at (734) 214-4780


         For more information on diesel retrofit options, visit
                                    November 2003