United States Air and Radiation EPA420-F-00-025
Environmental Protection July 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 is issuing a proposed rule
to address emissions of toxic air pollutants from mobile sources. In
addition to identifying 21 mobile source air toxics, this rule proposes
limits on the amount of benzene in gasoline. It also sets out a Technical
Analysis Plan whereby EPA will continue to conduct research and
analysis and to revisit in 2003 the need for and feasibility of additional
controls on toxic emissions from motor vehicles and fuels.
Highlights of the Proposed Rule
EPA is proposing a program to address emissions of hazardous air
pollutants from mobile sources. The proposal has four parts:
• For the first time, EPA identifies those compounds 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 does not include a list of
pollutants that should be classified as motor vehicle toxics. The list
of 21 MSATs (which is attached) includes various compounds that
result from fuel combustion in motor vehicle engines, as well as
certain metal compounds and diesel exhaust.
> Printed on Recycled Paper
-------
The proposal includes an evaluation of the effectiveness of federal
emission control programs in reducing emissions of these MSATs.
The analysis shows that existing programs put in place to reduce
motor vehicle emissions of ozone precursors, such as VOCs and
NOx, and particulate matter (PM), as well as programs that will
take effect in the future, will reduce MSATs for the next 20 years.
Existing and future programs that reduce MSATs include reformu-
lated gasoline (RFG) national low emission vehicles (NLEV) the
Tier 2 tailpipe standards for passenger vehicles and gasoline sulfur
control and the recently proposed program to establish new exhaust
standards for diesel-powered large trucks and buses and highway
diesel fuel sulfur control.
The proposal evaluates whether there are additional measures that
could be put in place at this time to reduce highway MSAT pollut-
ants even more. With regard to fuels-based controls, EPA proposes
to set maximum limits on the amount of benzene that can be added
to RFG and conventional gasoline. The proposed standards would
require refiners to maintain their average 1998-1999 benzene levels.
Benzene is a known human carcinogen that is a common compo-
nent of gasoline. With regard to vehicle-based controls, the proposal
concludes that the Tier 2 and proposed heavy duty standards are the
most stringent controls feasible at this time to reduce MSAT emis-
sions from motor vehicles.
The proposal sets up a process by which EPA will continue to
conduct research and analysis and, in 2003, revisit the question of
the need for and feasibility of additional controls on vehicles or
fuels.
Background
In response to public health concerns, Congress instructed EPA as part of
the Clean Air Act Amendments of 1990 to develop a program to address
emissions of toxic air pollutants from motor vehicles and their fuels.
First, EPA was instructed to study the need for and feasibility of control-
ling toxic emissions associated with motor vehicles and their fuels. EPA
completed this study in 1993 and updated it in 1999. The studies: Motor
Vehicle-Related Air Toxics Study, 1993, and Analysis of the Impacts of
Control Program on Motor Vehicles Toxics Emissions and Exposure in
Urban Areas Nationwide, November 1999, are available at http://
www.epa.gov/otaq/toxics.htm.
-------
Second, we were instructed to set standards for hazardous air pollutants
from motor vehicles and their fuels, or both. Those standards are to be
set based on available technology, taking existing standards, costs, noise,
energy and safety factors, and lead time into account.
and
Mobile sources are significant contributors of several key air toxics that
are also considered to be urban hazardous air pollutants. These include
1,3-butadiene, acetaldehyde, acrolein, benzene, and formaldehyde. In
addition, diesel exhaust comes virtually only from mobile sources. The
gasoline benzene standards proposed in this action will ensure that
refiners maintain the current RFG and anti-dumping fuel benzene limits.
While this proposal does not contain new, additional control programs to
reduce emissions of toxic air pollutants from mobile sources, it clarifies
that mobile source MSATs are expected to decline significantly over the
next 20 years, particularly gaseous air toxics and diesel exhaust, due to
existing and proposed mobile source emission control programs, includ-
ing RFG, NLEV, Tier 2, and the proposed large diesel truck and bus
standards.
to
This proposed rule is expected to impose negligible additional costs on
industry, since the proposed standards require that, beginning 2002,
refiners maintain the average 1998-1999 gasoline benzene levels.
EPA desires full public participation in arriving at rulemaking decisions.
The Agency solicits comments from all interested parties. Commenters
are especially encouraged to provide specific suggestions for changes to
any aspect of the proposal that they believe needs to be modified or
improved.
EPA will hold a public hearing in August 2000 and will accept written
comments on the NPRM for 30 days after the public hearing. For more
information on the public hearing or for instructions on submitting
written comments, please see the Federal Register notice. It is available
from the EPA Air and Radiation Docket by calling 202-260-7548; please
refer to Docket No. A-2000-12. In addition, the NPRM and related
documents are available at http://www.epa.gov/otaq/toxics.htm
-------
For
For further information on this proposed rule, please contact:
U.S. Environmental Protection Agency
Office of Transportation and Air Quality
Air Toxics Team
2000 Traverwood Drive
Ann Arbor, Michigan 48105
(734)214-4349
Proposed List of Mobile Source Air Toxics (MSATs)
Acctaldchydc*
Acrolein*
Arsenic compounds*
Benzene*
1.3 -Butadiene*
Chromium compounds*
Dioxin/Furans*
Diesel Exhaust
Ethylbenzene
Formaldehyde*
n-Hexane
Lead compounds*
Manganese compounds*
Mercury compounds*
MTBE
Naphthalene
Nickel compounds*
POM (Sum of 7 PAHs)*
Styrene
Toulene
Xylene
Also on the list of urban HAPs for the Urban Air Toxics Strategy
------- |