[Federal Register Volume 59, Number 189 (Friday, September 30, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-24251]
[[Page Unknown]]
[Federal Register: September 30, 1994]
=======================================================================
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 51
[FRL-4895-4]
Air Quality: Revision to Definition of Volatile Organic
Compounds--Exclusion of Acetone
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
-----------------------------------------------------------------------
SUMMARY: The EPA is proposing to revise its definition of volatile
organic compounds (VOC) for purposes of preparing State implementation
plans (SIP's) to attain the national ambient air quality standards
(NAAQS) for ozone under title I of the Clean Air Act (Act) and for the
Federal implementation plan for the Chicago ozone nonattainment area.
The proposed revision would add acetone to the list of compounds
excluded from the definition of VOC on the basis that these compounds
have negligible contribution to tropospheric ozone formation.
DATES: Comments on this proposal must be received by November 29, 1994.
ADDRESSES: Comments should be submitted in duplicate (if possible) to:
Air and Radiation Docket and Information Center (6102), Attention:
Docket No. A-94-26, U.S. Environmental Protection Agency, 401 M Street,
SW., Washington, DC 20460. Comments should be strictly limited to the
subject matter of this proposal, the scope of which is discussed below.
Public Hearing: If anyone contacts EPA requesting a public hearing,
it will be held at Research Triangle Park, North Carolina. Persons
wishing to request a public hearing, wanting to attend the hearing or
wishing to present oral testimony should notify Mr. William Johnson,
Air Quality Management Division (MD-15), U.S. Environmental Protection
Agency, Research Triangle Park, North Carolina 27711, telephone (919)
541-5245. The EPA will publish notice of a hearing, if a hearing is
requested, in the Federal Register. Any hearing will be strictly
limited to the subject matter of the proposal, the scope of which is
discussed below.
This action is subject to the procedural requirements of section
307(d)(1) (B), (J), and (U) of the Act, and 42 U.S.C. 7607(d)(1) (B),
(J), and (U). Therefore, EPA has established a public docket for this
action, A-94-26, which is available for public inspection and copying
between 8 a.m. and 4 p.m., Monday through Friday, at EPA's Central
Docket Section, room M-1500, 401 M Street, SW., Washington, DC 20460. A
reasonable fee may be charged for copying.
FOR FURTHER INFORMATION CONTACT: William Johnson, Office of Air Quality
Planning and Standards, Air Quality Management Division (MD-15),
Research Triangle Park, NC 27711, phone (919) 541-5245.
SUPPLEMENTARY INFORMATION:
I. Background
Three petitions have been received by the EPA asking that acetone
be added to the list of negligibly-reactive compounds in the definition
of VOC at 40 CFR 51.100(s). These petitions were submitted by Eastman
Chemical Company and Hoechst Celanese Corporation on April 26, 1993,
Hickory Springs Manufacturing Company on May 6, 1993, and the Chemical
Manufacturers Association on May 14, 1993. Along with their petitions
and in supplemental submissions, these organizations submitted a
variety of scientific materials which support the assertion that
acetone is of negligible photochemical reactivity. These materials have
been added to the docket for this rulemaking.
The petitioners based their request for the exclusion of acetone on
a demonstration that the photochemical reactivity of acetone is not
appreciably different from that of ethane, which is the most reactive
compound on the current list of compounds which are named in the
definition of VOC as being of negligible reactivity. Acetone's
photochemical reactivity arises through two chemical pathways: through
reaction with hydroxyl (OH) radicals (kOH reactivity) and through
photolysis. Data on the reaction of OH radicals with various organic
compounds are reported in a review article (Atkinson, R. (1990),
``Gas--Phase Tropospheric Chemistry of Organic Compounds: A Review.''
Atmospheric Environment, 24 A:1-41) which gives the following rate
constants for reactions of ethane and acetone with OH:
Ethane: 2.68 x 10-13 cc/molecule/sec.
Acetone: 2.26 x 10-13 cc/molecule/sec.
Thus, if the kOH reactivities alone are considered, acetone is
less reactive than ethane. Unlike ethane, however, acetone undergoes
photodecomposition, or photolysis, in the atmosphere to form radicals,
which tend to cause increased rates of ozone formation. Total
reactivity of acetone, considering both kOH reactivity and
photolysis, was the subject of a special study reported recently
(Carter, W. P. L. et al., ``An Experimental and Modeling Study of the
Photochemical Ozone Reactivity of Acetone,'' University of California/
Riverside, December 10, 1993).
The Carter report describes a series of environmental chamber
experiments and computer model simulations carried out to assess the
tendency of acetone to promote ozone formation under atmospheric
conditions, relative to that of ethane. This was done by calculating
and comparing the ``incremental reactivities'' of acetone and ethane
for a variety of atmospheric conditions representing ozone episodes in
39 urban areas throughout the United States.
``Incremental reactivity'' is the most recently proposed
quantitative measure of the degree to which a VOC contributes to ozone
formation in a photochemical air pollution episode. It is defined as
the amount of additional ozone formation resulting from the addition of
a small amount of VOC to the urban emissions, divided by the amount of
compound added. This measure of reactivity takes into account all of
the factors by which a VOC affects ozone formation, including the
effect of the environment where the VOC reacts. The latter is important
because the amount of ozone formation caused by the reactions of a VOC
depends significantly on the conditions within the polluted atmosphere,
such as VOC to nitrogen oxide (NOX) ratio, VOC composition, and
sunlight intensity. Figure 1 shows distribution plots of the reactivity
of acetone relative to that of ethane for the 39 urban scenarios used,
where reactivity is defined in terms of grams of ozone formed per gram
of VOC emitted. (Use of the unit grams of ozone formed per gram of VOC
emitted is significant. Another way of defining reactivity is in terms
of grams of ozone formed per mole of VOC emitted, which would give
different results. For practicality, the EPA has elected to adopt the
grams ozone per gram VOC basis, since grams (or tons), rather than
moles, is the mass unit used in regulations dealing with VOC
emissions.) In Figure 1, acetone/ethane reactivity ratios less than 1.0
indicate scenarios where acetone is less reactive than ethane. The
acetone/ethane reactivity ratio, as reported by Carter, appears to have
widely varying values among the 39 urban scenarios and to reflect, with
a few exceptions, slightly lower reactivity for acetone. For one
scenario, which represents unusually high NOX conditions, acetone
was calculated to be over two times more reactive than ethane. This is
due to the unusually low reactivity of ethane for that particular
scenario, rather than to higher acetone reactivity. Figure 2 shows the
variability of ethane reactivity relative to that of a ``typical''
urban VOC mix. Figure 2 also shows that the reactivity range of acetone
falls entirely within the range for ethane.
BILLING CODE 6560-50-P
TP30SE94.002
TP30SE94.003
BILLING CODE 6560-50-C
Although there are uncertainties in acetone's atmospheric photo-
oxidation mechanism and in the other aspects of ozone-related
atmospheric photochemistry, one can reasonably deduce, based on the
Carter report, that acetone and ethane probably have nearly the same
reactivity for most sets of environmental conditions.
Additional studies have been conducted on the relative reactivity
of acetone in Europe. For example, R. G. Derwent and M. E. Jenkins
(Hydrocarbons and the Long-range Transport of Ozone and PAN Across
Europe, Atmospheric Environment, vol 24A, pp 1661-1678, 1991) used a
chemical mechanism to calculate ozone impacts of acetone, ethane, and
other VOC for three trajectories across Europe. The photochemical
trajectory model the authors employed was developed at Harwell
Laboratory (United Kingdom) and was used to calculate the photochemical
ozone creation potential (POCP) values for 69 organic compounds,
including acetone. The POCP values were assigned to VOC species
according to a relative scale, with ethylene having a value of 100. Dr.
Derwent reported in a letter (January 27, 1994) to EPA that: ``A
comparison of POCP's for ethane and acetone in the work of my
colleagues at Harwell Laboratory, which incidentally updates the
acetone entries in the VOC Protocol Annex, gives 8.2 4.0
and 9.2 2.0, respectively.'' The difference between these
numbers is not considered to be statistically significant.
If acetone is accepted as having negligible photochemical
reactivity, exempting acetone from regulation as an ozone precursor
could contribute to the achievement of several important environmental
goals. For example, acetone can be used as a substitute for several
compounds that are listed as hazardous air pollutants (HAP) under
section 112 of the Act. Methylene chloride and methyl chloroform are
HAP that are used for metal cleaning and for flexible polyurethane foam
blowing. Other HAP, such as toluene, are often used as solvents in
paints and coatings. Acetone can substitute for these substances in
some circumstances.
Acetone can also be used as a substitute for ozone depleting
substances (ODS) which are active in depleting the stratospheric ozone
layer. Under the London Amendments to the Montreal Protocol on
substances that deplete the ozone layer (``Montreal Protocol''), the
United States agreed to phase out production and consumption of certain
chlorofluorocarbons (CFC) by the year 2000 and methyl chloroform by
2005 (see 58 FR 15016 (March 18, 1993)). In 1990, Congress added title
VI to the Act in part to provide for the implementation of this
phaseout (see 42 U.S.C. 7671 et seq.). The 1990 Amendments specified an
initial list of Class I and Class II ODS, authorizing EPA to add
compounds to both lists depending on a given compound's potential to
contribute to stratospheric ozone depletion, (Id. Sec. 7671a.) The 1990
Amendments further required phaseout of the production and consumption
of Class I ODS by 2000, methyl chloroform by 2002, and Class II ODS by
2030 (see 42 U.S.C. 7671c, 7671d). At the fourth meeting, in 1992, of
the parties to the Montreal Protocol in Copenhagen, Denmark, the
parties adjusted the phaseout schedules for Class I substances under
the Montreal Protocol to phase out Class I CFC and methyl chloroform by
1996. In 1993, EPA proposed to accelerate the phaseout of Class I CFC
and methyl chloroform in order to discontinue use of these compounds
after January 1, 1996 (see 58 FR 15022).
As a result of these phaseout deadlines, there is a need to develop
substitutes for ODS. Allowing wider use of acetone will facilitate the
transition away from ODS without adversely affecting efforts to control
ground level ozone concentrations. For example, chlorofluorocarbon-11
and methyl chloroform have been used as foam-blowing agents in the
manufacture of polyurethane foam. These compounds are also used in
metal cleaning in the aircraft manufacturing industry. Both CFC-11 and
methyl chloroform are listed as Class I substances under title VI of
the Act, i.e., as substances that have the highest stratospheric ozone-
depleting potential. Acetone may be able to be used as a foam-blowing
agent and cleaning agent in place of these chemicals.
The EPA has already listed acetone as an acceptable ozone-depleting
substance substitute under the program known as the ``Significant New
Alternatives Policy'' (SNAP) program, (59 FR 13044, March 18, 1994).
Within the context of the SNAP rule, substitutes are ``acceptable'' if
they are technically feasible to be used as an alternative to an ODS
for particular uses and give reduced overall risk to human health and
the the environment compared to the ODS they replace. In the SNAP rule,
EPA listed acetone as an acceptable substitute for flexible
polyurethane foam blowing (59 FR 13132). The SNAP rule lists ketones
(which include acetone) as an acceptable substitute for solvent
cleaning in metal cleaning, electronics cleaning, and precision
cleaning (59 FR 13134). Ketones are also listed in the SNAP rule as an
acceptable substitute solvent for aerosols and for adhesives, coatings,
and inks (59 FR 13145).
In each of these areas of concern, toxic air emissions and
depletion of stratospheric ozone, adding acetone to the list of
negligibly-reactive VOC will support the EPA's pollution prevention
efforts. By enacting the Pollution Prevention Act of 1990, Congress
established as a national policy that ``pollution should be prevented
or reduced at the source whenever feasible'' (42 U.S.C. 13). An
important part of EPA's pollution prevention strategy is encouraging
companies to use substitutes in their production processes that are
more environmentally benign than the substances they currently use. For
example, in its blueprint for a comprehensive national pollution
prevention strategy, (56 FR 7849 (February 26, 1991)), the EPA
recognized that the definition of pollution prevention includes a
``switch to non-toxic or less toxic substitutes'' (Id. at 7854).
National air emissions of acetone from industrial sources were
estimated to be 80,000 tons per year in 1991. It should be noted that
due to the high volatility of acetone, increased use of acetone for
metal cleaning will most likely increase emissions of the compound to
the air.
II. The EPA Response to the Petition
Based on the scientific data presented in the material submitted by
the petitioners, EPA accepts the conclusion that acetone is not
appreciably different from ethane in terms of photochemical reactivity.
The EPA is responding to the petitions by proposing in this notice to
add acetone to the list of compounds appearing in 40 CFR 51.100(s) that
are considered to be negligibly reactive and are thus excluded from the
definition of VOC for ozone SIP and ozone control purposes. The revised
definition will apply in the Chicago ozone nonattainment area pursuant
to the 40 CFR 52.741(a)(3) definition of volatile organic material or
volatile organic compound. States are not obligated to exclude from
control as a VOC those compounds that EPA has found to be negligibly
reactive. However, if this proposal is made final, EPA will not enforce
measures controlling acetone as part of a federally-approved ozone SIP.
In addition, once this proposal is made final, States should not
include acetone in their VOC emissions inventories for determining
reasonable further progress under the Act (e.g., section 182(b)(1)) and
may not take credit for controlling acetone in their ozone control
strategy. Further, after this proposal is made final, acetone may not
be used for emissions netting (e.g., 40 CFR 51.166(b)(2)(c)),
offsetting (40 CFR appendix S), or trading with reactive VOC (Emissions
Trading Policy Statement, 51 FR 43814, December 4, 1986 and Economic
Incentive Program Rules, 59 FR 16690, April 7, 1994).
Since acetone will no longer be treated as a VOC, a State should
revise its base year inventory and plans that rely on that inventory
(e.g., the 15 percent plan) to remove acetone and the VOC emissions
reduction credit taken from controlling acetone. To avoid unnecessary
work, however, States may account for the fraction of the VOC inventory
that acetone comprises or the amount of reduction claimed for
controlling acetone. If the acetone fraction in the inventory or the
amount of control claimed is not significant for a particular area, EPA
would not expect a State to revise its emissions inventory or a plan
based on that inventory to account for the revised VOC definition.
In addition, corrections are made to the names of three compounds
which have previously been exempted from the definition of VOC; 1,1,1-
trichloro-2,2,2-trifluoroethane (CFC-113) is changed to 1,1,2-
trichloro-1,2,2-trifluoroethane (CFC-113); chlorodifluoromethane (CFC-
22) is changed to chlorodifluoromethane (HCFC-22); and trifluoromethane
(FC-23) is changed to trifluoromethane (HFC-23). These changes are
corrections to nomenclature only and are not substantive.
Pursuant to 5 U.S.C. 605(b), I hereby certify that this action will
not have a significant economic impact on a substantial number of small
entities because it relaxes current regulatory requirements rather than
imposing new ones. The EPA has determined that this rule is not
``significant'' under the terms of Executive Order 12866 and is,
therefore, not subject to Office of Management and Budget (OMB) review.
This action does not contain any information collection requirements
subject to OMB review under the Paperwork Reduction Act of 1980 (44
U.S.C. 3501 et seq.).
Assuming this rulemaking is subject to section 317 of the Act, the
Administrator concludes, weighing the Agency's limited resources and
other duties, that it is not practicable to conduct an extensive
economic impact assessment of today's action since this rule will relax
current regulatory requirements. Accordingly, the Administrator simply
notes that any costs of complying with today's action, any inflationary
or recessionary effects of the regulation, and any impact on the
competitive standing of small businesses, on consumer costs, or on
energy use, will be less than or at least not more than the impact that
existed before today's action.
List of Subjects in 40 CFR Part 51
Administrative practice and procedure, Air pollution control,
Carbon monoxide, Intergovernmental relations, Lead, Nitrogen dioxide,
Ozone, Particulate matter, Reporting and recordkeeping requirements,
Sulfur oxides, Volatile organic compounds.
Dated: September 23, 1994.
Carol M. Browner,
Administrator.
For reasons set forth in the preamble, part 51 of Chapter I of
title 40 of the Code of Federal Regulations is proposed to be amended
as follows:
PART 51--REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF
IMPLEMENTATION PLANS
1. The authority citation for part 51 continues to read as follows:
Authority: 42 U.S.C. 7410(a)(2), 7475(e), 7502(a) and (b), 7503,
7601(a)(1), and 7620.
2. Section 51.100 is amended by revising paragraph (s)(1)
introductory text to read as follows:
Sec. 51.100 Definitions.
* * * * *
(s) * * *
(1) This includes any such organic compound other than the
following, which have been determined to have negligible photochemical
reactivity: methane; ethane; methylene chloride (dichloromethane);
1,1,1-trichloroethane (methyl chloroform); 1,1,2-trichloro-1,2,2-
trifluoroethane (CFC-113); trichlorofluoromethane (CFC-11);
dichlorodifluoromethane (CFC-12); chlorodifluoromethane (HCFC-22);
trifluoromethane (HFC-23); 1,2-dichloro 1,1,2,2-tetrafluoroethane (CFC-
114); chloropentafluoroethane (CFC-115); 1,1,1-trifluoro 2,2-
dichloroethane (HCFC-123); 1,1,1,2-tetrafluoroethane (HFC-134a); 1,1-
dichloro 1-fluoroethane (HCFC-141b); 1-chloro 1,1-difluoroethane (HCFC
142b); 2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124); pentafluoroethane
(HFC-125); 1,1,2,2-tetrafluoroethane (HFC-134); 1,1,1-trifluoroethane
(HFC-143a); 1,1-difluoroethane (HFC-152a); acetone; and perfluorocarbon
compounds which fall into these classes:
* * * * *
[FR Doc. 94-24251 Filed 9-29-94; 8:45 am]
BILLING CODE 6560-50-P
