United States Air and Radiation EPA420-F-00-055
Environmental Protection December 2000
Agency
Office of Transportation and Air Quality
Regulatory
Announcement
Control of Emissions of Hazardous
Air Pollutants from Mobile Sources
The U.S. Environmental Protection Agency (EPA) is issuing a final rule
to address emissions of hazardous air pollutants (or "air toxics") from
mobile sources. In addition to identifying 21 mobile source air toxics, this
rule sets new gasoline toxic emission performance standards. It also
sets out a Technical Analysis Plan to continue to conduct research and
analysis on mobile source air toxics. Based on the results of that
research, EPA will conduct a future rulemaking, to be completed no later
than July 1, 2004, in which we will revisit the feasibility and need for
additional controls for nonroad and highway engines and vehicles and
their fuels.
Background
In response to public health concerns, Congress instructed EPA in 1990
to address emissions of air toxics from motor vehicles and their fuels.
These instructions, contained in Section 202(1) of the Clean Air Act,
consist of two parts. First, we were instructed to study the need for and
feasibility of controlling emissions of toxic air pollutants associated with
motor vehicles and their fuels. In this section, benzene, 1,3-butadiene,
and formaldehyde were singled out for particular consideration. We
completed this study in 1993 and updated it in 1999. The studies are:
Motor Vehicle-Related Air Toxics Study, 1993 (Publication No. EPA420-
R-93-005) and Analysis of the Impacts of Control Program on Motor
Vehicles Toxics Emissions and Exposure in Urban Areas Nationwide,
November 1999 (Publication No. EPA420-R-99-029). These reports are
available at http://www.epa.gov/otaq/toxics.htm.
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Second, we were instructed to set standards
for hazardous air pollutants from motor
vehicles and their fuels, or both. Those
standards are to be promulgated under
Section 202(a) or Section 21 l(c) of the Act
and must address at least benzene and
formaldehyde. They are to be set based on
available technology, taking existing stan-
dards, costs, noise, energy and safety
factors, and lead time into account.
Highlights of the Rule
EPAs mobile source air toxics rule has four
main parts:
• For the first time, EPA identifies com-
pounds that should be considered
Mobile Source Air Toxics (MSATs).
This is necessary because, unlike the
provisions governing toxic emissions
from stationary sources, the Clean Air
Act provisions for motor vehicle toxics
do not provide a list of pollutants to be
controlled. Our list of 21 MSATs in-
cludes various compounds that are
emitted from mobile sources, including
several volatile organic compounds
(VOCs) and metals, as well as diesel
particulate matter plus diesel exhaust
organic gases (DPM+DEOG).
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We evaluate the effectiveness of current
controls in reducing highway emissions
of these MSATs. Our analysis shows
that the programs we put in place to
reduce ozone and PM inventories,
including the reformulated gasoline
(RFG) program, national low emission
vehicle (NLEV) program, emissions
standards for passenger vehicles and
gasoline sulfur control requirements
(Tier 2), and the 2007 heavy-duty
vehicle standards and highway diesel
fuel sulfur control requirements, are
expected to yield significant reductions
of mobile source air toxics.
We evaluate whether there are addi-
tional air toxics controls that could be
put in place at this time to reduce
highway MSAT inventories even more.
With regard to fuels-based controls, we
set new gasoline toxic emission perfor-
mance standards that will ensure that
refiners maintain their average 1998-
2000 gasoline toxic emission perfor-
mance levels. With regard to vehicle-
based controls, we conclude that our
Tier 2 and heavy-duty 2007 standards
are the most stringent controls feasible
at this time to reduce MSAT emissions
from highway vehicles and engines.
We establish a Technical Analysis Plan
which EPA will implement to continue
to conduct research and analysis on
mobile source air toxics. Based on the
information developed through this
research, EPA will conduct a future
rulemaking, to be completed no later
than July 1, 2004, in which we will
revisit the feasibility and need for
additional controls for both nonroad
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and on-highway engines and vehicles
and their fuels.
Health and Environmental
Benefits
Mobile sources are a significant contributor
to national inventories of several key air
toxics that are also considered to be urban
hazardous air pollutants as identified in
EPA's Integrated Urban Air Toxics Strat-
egy. These include 1,3-butadiene, acetalde-
hyde, acrolein, benzene, and formaldehyde.
In addition, DPM+DEOG is emitted
virtually only from mobile sources. This
rule clarifies that the mobile source contri-
bution to national levels of air toxics is
expected to decline significantly over the
next 20 years, particularly gaseous air
toxics and DPM+DEOG, due to other
mobile source emission control programs,
including RFG, NLEV, Tier 2, and the
heavy-duty 2007 standards. The gasoline
toxics emission performance standards
contained in this rule will help ensure that
refiners maintain their average 1998-2000
gasoline toxic emission performance levels.
Cost to Industry
This rule is not expected to impose any
costs on industry. EPA believes that no
refinery capital expenditures will be
needed to comply with the requirements of
the gasoline toxic emission performance
standards since they are not technology-
forcing but instead require that, beginning
2002, refiners maintain their average 1998-
2000 gasoline toxic emission performance
levels.
For More Information
You can access the final rule and related
documents electronically on the Office of
Transportation and Air Quality (OTAQ)
Web site at:
http://www.epa.gov/otaq/toxics.htm
For further information on this final rule,
please contact the Mobile Source Air
Toxics Team at:
U.S. EPA
OTAQ
2000 Traverwood Drive
Ann Arbor, Michigan 48105
(734)214-4349
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