October 16, 1995



MEMORANDUM

SUBJECT:  Definition of Regulated Pollutant for Particulate
          Matter for Purposes of Title V
     
FROM:     Lydia N. Wegman, Deputy Director  /s/
          Office of Air Quality Planning and Standards (MD-10)

TO:       See Addressees


     In a guidance memorandum dated April 26, 1993, the Agency
clarified its interpretation of the term "regulated air
pollutant" as defined in the operating permit rule (see 40 CFR
70.2).  Recently, many discussions have been held concerning the 
application of this definition to sources of particulate matter
under the title V operating permit program.  Today's memorandum
provides additional guidance to assist permitting authorities in
determining which sources of particulate matter are subject to
the requirements of title V.

     There are different forms of particulate matter for which
controls are required by various regulations.  The April 26, 1993
memorandum listed PM-10 and total suspended particulates as
regulated forms of particulate matter and, consequently,
regulated air pollutants.  The EPA has recently reevaluated this
finding and has concluded that its definition of regulated air
pollutant under title V applies only to emissions of PM-10.  A
detailed discussion of the basis for this conclusion is attached.

     Today's guidance should be used to determine which sources
of particulate matter are subject to minimum title V requirements
and fee calculations.  The Federal minimum for applicability of
title V to sources of particulate matter should be based on the
amount of emissions of PM-10, not particulate matter, that the
source has the potential to emit.  Some sources [such as country
grain elevators, aggregate (rock, gravel, and sand) handling
operations, and some mining operations] may not be major sources of PM-10 even though they would have been considered
major sources of particulate matter.  

     This guidance does not change any requirements for sources
to comply with emission limitations or work practice standards as
described in State implementation plans (SIPs) and new source
performance standards (NSPS).  For example, the required
procedures for determining compliance with NSPS continue to be
based on in-stack measurements of particulate emissions or
visible emissions observations (i.e., Test Methods 5, 9, 17, and
22, and Performance Specification 1).  The Federal minimum is
that if sources are major, then they must obtain title V
operating permits which include all applicable requirements. 
Therefore, if a source is major for particulate matter, but not
for PM-10, the Federal minimum would be that a title V operating
permit would not be required if the only pollutant that would
make the source major is particulate matter.  Any requirements to
comply with NSPS or SIPs would remain in effect, however.  

     This clarification of PM-10's status as the regulated
pollutant will cause some difficulties in estimating emissions; 
however, tools are available for many source categories.  For
example, although some 1900 particulate matter emission factors
can be found in the document referred to as "AP-42," there are
also over 1200 PM-10 factors.  In addition, category specific
particle-size distributions are available for a number of other
categories on EPA's data bases.
     
     This revision of previous guidance constitutes a change only
with regard to the title V operating permit program.  It does not
change any other interpretations or requirements that have been
previously provided for implementing the Clean Air Act.  

     The policies set forth in this memorandum are intended
solely as guidance and not final Agency action.  This guidance
cannot be relied upon to create any rights enforceable by any
party.  For further information on the title V aspects of this
guidance, please contact Leo Stander at 919-541-2402, and for
further information on emissions estimation techniques, please
contact David Mobley at 919-541-4676.

Attachment

Addressees:
Director, Office of Ecosystem Protection, Region I
Director, Air & Waste Management Division, Region II
Director, Air, Radiation & Toxics Division, Region III
Director, Air, Pesticide & Toxics Management Division, Region IV
Director, Air and Radiation Division, Region V
Director, Multimedia Planning and Permitting Division, Region VI
Director, Air, RCRA and TSCA Division, Region VII
Director, Office of Pollution Prevention, State and Tribal,
Region VIII
Director, Air & Toxics Division, Region IX
Director, Office of Air, Region X

cc:  Chief, Air Branch, Regions I-X
     Operating Permits Program Contact, Regions I-X
     OAQPS Division Directors

REGULATED AIR POLLUTANT:  PARTICULATE MATTER



     This document explains the Environmental Protection Agency
(EPA) policy that, at this time, PM-10 is considered to be the
only regulated form of particulate matter.  Today's policy
supersedes prior EPA statements which indicated that a second
regulated form of particulate matter existed.  As explained
further below, such prior statements were based on the fact that
EPA had established specific compliance methods for sources of
particulate matter under the new source performance standards
(NSPS).  The immediate consequence of this policy is that under
the title V operating permits program only PM-10 is considered by
EPA to be the regulated form of particulate matter for
applicability and fee purposes.  This policy does not affect (1)
existing requirements under the NSPS that a source comply with
applicable performance standards for particulate matter emissions
or (2) provisions contained in State implementation plans for
particulate matter, including existing particulate emissions
limitations, which have been approved by EPA and are relied upon
to attain or maintain the national ambient air quality standards
(NAAQS) for particulate matter.

Background

     The part 70 regulations for State title V operating permit
programs define "regulated air pollutant" at 40 CFR 70.2.  This
definition is intended to ensure that permitting authorities
receive appropriate information on all pollutants which are
"regulated" under the Clean Air Act (Act) and emitted by a
source.  The term "regulated air pollutant" is intended to
reflect all pollutants subject to a standard, regulation, or
requirement by including in the definition five specific
categories of pollutants which would be considered regulated air
pollutants.  Questions have arisen, based on an EPA-issued
memorandum on April 26, 1993, entitled "Definition of Regulated
Air Pollutant for Purposes of Title V," concerning how many
regulated forms of particulate matter the definition includes. 
The memorandum identified two regulated indicators--PM-10 and
total suspended particulate (TSP).  The PM-10 was considered
regulated because it was a pollutant for which a NAAQS had been  promulgated.  The TSP was listed as a pollutant regulated under
the NSPS.

     Implied in the April 1993 memorandum (though not explicitly
stated therein) was the interpretation that the NSPS for
particulate matter--which measures a different form of
particulate than PM-10--automatically constituted a separate
regulated indicator for particulate matter.  The EPA has
reevaluated this interpretation and has concluded that it is no
longer appropriate.  It is EPA's current position that different
indicators for particulate matter may be used as surrogate
measures where appropriate for controlling ambient concentrations
of PM-10 without specifically requiring such surrogates
themselves to be regarded as regulated pollutants.  The EPA
further believes that the basis for determining what the
regulated pollutant or indicator is for particulate matter should
focus on EPA's intent as evidenced primarily by the underlying
statutory authority used by EPA to subject the relevant air
pollutant to a standard, regulation or requirement, and by
statements made by EPA in connection with its promulgation.  This
interpretation does not preclude EPA from specifically choosing
to regulate a different indicator for particulate matter under
the authority of section 111 of the Act.  However, as explained
below, it was not EPA's intent to do so for any of the NSPS
promulgated to date for particulate matter.

Section 109 authority

     To date, EPA's efforts to regulate particulate matter have
relied primarily upon the joint authorities of sections 108 and
109 of the Act.  Section 108 directs the Administrator to
identify pollutants which may reasonably be anticipated to
endanger public health or welfare and to issue air quality
criteria for those pollutants.  Section 109 of the Act then
governs the establishment and revision of NAAQS for criteria
pollutants.  On April 30, 1971, EPA promulgated the original
NAAQS for particulate matter.  The NAAQS defined ambient
concentrations of particulate matter measured as TSP (ambient
compliance sampling achieved by "high volume" samplers which
collect particulate matter up to a nominal size of 25 to 45
micrometers).  On July 1, 1987, EPA revised the NAAQS for
particulate matter, replacing the TSP indicator with the new 
PM-10 indicator.Section 111 authority

     The control of particulate matter is also required by
various NSPS under section 111 of the Act.  Section 111 generally
requires EPA to promulgate NSPS for any category of stationary
sources that "...causes, or contributes significantly to, air
pollution which may reasonably be anticipated to endanger public
health or welfare."  The EPA promulgated numerous NSPS
specifically to address the criteria pollutant, particulate
matter, during the period of time when the NAAQS for particulate
matter were measured as TSP.  While EPA indicated that
particulate matter was a criteria pollutant for which NAAQS had
been promulgated, EPA compliance tests used to meet the specific
NSPS for particulate matter did not use the same indicator as the
indicator for the NAAQS for particulate matter.  Instead, such
compliance tests typically involved measures of particulate
matter in the stack using emissions testing procedures (e.g.,
Method 5) that do not take into account particle size.  
Nevertheless, preamble discussions to certain of these NSPS show
that EPA regarded the pollutant of concern to be the criteria
pollutant for which NAAQS had been promulgated.  See e.g., NSPS
for Phosphate Rock Plants (9/21/79), Nonmetallic Mineral
Processing Plants (8/1/85), and Calciners and Dryers in Mineral
Industries (9/28/92).  

     With the promulgation of PM-10 NAAQS in 1987, EPA considered
the issue of whether to revise the NSPS with respect to
particulate matter.  In a July 1, 1987 Federal Register notice,
EPA acknowledged that the indicator for particulate matter used
to measure compliance with the NSPS was different from both TSP
and PM-10 (52 FR 24710).  The EPA stated, therein, that the
existing NSPS "that reflect the best demonstrated control
technology for particulate matter have the effect of controlling
PM-10."  The EPA later decided that, at least until further
studies could be accomplished, the existing NSPS for particulate
matter would serve as adequate surrogates for limiting ambient
amounts of PM-10, the intended "regulated air pollutant."  The
NSPS promulgated after 1987 have continued to base compliance on
in-stack emissions test methods which measure particulate
emissions.  Based on this regulatory history, it is EPA's
position that the use of particulate matter emissions as the
measure of compliance under various NSPS for particulate matter
does not, in itself, constitute a new regulated air pollutant,
but is simply designed as a surrogate measure of particulate
matter to establish effective performance standards which limit
the emissions of the regulated indicator, PM-10. 

     While the EPA contends that the control of a pollutant under
an NSPS does not automatically result in that pollutant beingconsidered regulated if the intended pollutant is already being
regulated under separate legal authority, the EPA does
specifically rely upon the NSPS to regulate certain pollutants. 
A case in point is the NSPS for kraft pulp mills at 40 CFR 60
subpart BB, which includes limitations for emissions of total
reduced sulfur compounds.  This and other specific non-criteria
pollutants are considered "regulated air pollutants" by virtue of
the fact that EPA intended for them to be regulated by the NSPS,
since they are not regulated elsewhere.  

Other examples of surrogate measures

     The EPA has used the measurement of particulate matter
emissions for compliance purposes as the surrogate for
controlling the pollutant intended to be regulated in the         
section 112 context as well.  Examples of such situations are the
NESHAP for arsenic and asbestos at 40 CFR 61.140 and 61.170,
respectively.  The EPA listed asbestos and arsenic as hazardous
pollutants under section 112 of the Act.  Subsequently, the EPA
promulgated standards for several sources of asbestos and for
inorganic arsenic emissions from primary copper smelters which
require compliance with a particulate matter emissions limit
using Method 5 and opacity monitoring (51 FR 27956, August 4,
1986 at 27981.)  Nevertheless, the EPA considers arsenic and
asbestos, as listed in accordance with section 112 of the Act, to
be regulated pollutants in these instances. 

Other implications

     Nothing stated in this current policy is intended to negate,
void or otherwise affect limits expressed as particulate matter
emissions under any NSPS, or the enforceability of existing
standards contained in State control strategies for PM-10 which
may actually require compliance with other indicators for
particulate matter.  The EPA historically has allowed States to
rely upon their original SIPs based on the control of particulate
matter emissions to demonstrate attainment with the PM-10 NAAQS. 
The EPA continues to consider these plans to be adequate so as to
remain in effect and be enforceable as long as they continue to
be used to demonstrate attainment of the regulated indicator for
particulate matter, PM-10.