1

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION 1

5 POST OFFICE SQUARE, SUITE 100

BOSTON, MA 02109-3912

Memorandum

Date: July 15, 2016

Subject: Technical Support Document: Vermont SIP Revisions relating to New Source Review 

permitting and certain other requirements, submitted in 1993, 2011, and 2014

From: Donald Dahl

Environmental Engineer

Thru: Ida E. McDonnell, Manager

Air Permits, Toxics, and Indoor Programs Unit

To: File

The following table provides EPA Region 1’s analysis of Vermont’s 1993, 2011, and 2014 SIP 

submittals and provides the agency’s rationale for concluding that the revisions to Vermont’s 

regulations, which EPA is approving in the associated federal register notice, are consistent with 

EPA’s new source review regulations codified at 40 CFR 51.160-166, and with other applicable 

Clean Air Act requirements. The table below is organized by the State’s individual SIP revision 

requests submitted in 1993, 2011, and 2014.
2

1993

August 9, 1993 SIP Submittal

Revisions to Section 5-101 (Definitions)

State Definition EPA Definition Action

"Federally Enforceable" means all limitations and 

conditions which are enforceable by the U.S. 

Environmental Protection Agency, whether

contained in federal regulations, a state 

implementation plan, or construction or operating 

permits.

40 CFR 51.166(b)(17): Federally enforceable means all 

limitations and conditions which are enforceable by the 

Administrator, including those requirements developed 

pursuant to 40 CFR parts 60 and 61, requirements within any 

applicable State implementation plan, any approved pursuant 

to 40 CFR part 51, subpart I, including operating permits 

issued under an EPA-approved program that is incorporated 

into the State implementation plan and expressly requires 

adherence to any permit issued under such program.

permit requirements established pursuant to 40 CFR 52.21 or 

under regulations

Approve: The State’s 

definition is consistent 

with EPA’s definition.
3

2011 Submittal

February 14, 2011

Revisions to Section 5-101 (Definitions)

State Definition EPA Definition Action

“Federal Land Manager” means the Secretary of the department with 

authority over a Class I Federal area or his or her representative.

40 CFR 51.166(b)(24): Federal Land 

Manager means, with respect to any lands in 

the United States, the Secretary of the 

department with authority over such lands.

Approve: The State’s 

definition is consistent 

with EPA’s definition 

for use within the PSD 

permitting program. The 

State is required to 

involve the Federal 

Land Manager for 

projects impacting Class 

I areas.

Revisions to Section 5-251 (Control of Nitrogen Oxides Emissions)

State Regulation Action

(1) No person shall discharge, or cause, allow or permit emissions

of oxides of nitrogen, expressed as NOx, from any steam 

generating fuel burning equipment with a heat input capacity of 

250 million BTU's per hour or more in excess of:

(a) 0.36 grams per million calories heat input (0.20 pounds 

per million BTU) derived from gaseous fossil fuel.

(b) 0.54 grams per million calories heat input (0.30 pounds 

per million BTU) derived from liquid fossil fuel.

(c) 1.26 grams per million calories heat input (0.70 pounds 

per million BTU) derived from solid fossil fuel (except 

lignite or a fossil fuel containing 25 percent by weight, or 

more of coal refuse).

Approve: Vermont changed the applicability of this section from “fuel 

burning equipment with a heat input capacity of 250 MMBtu/hr or 

more” to “steam generating fuel burning equipment with a heat input 

capacity of 250 MMBtu/hr or more.” The term “Fuel burning 

equipment” is defined in the SIP as “any furnace, boiler, and/or 

apparatus, used in the process of burning fuel for the primary purpose 

of producing heat or power.” This definition would include process 

heaters that use a fluid other than water. In a letter dated July 13, 2016, 

Vermont informed EPA that at this time Vermont does not have any 

fuel burning equipment above 250 MMBtu/hr that is not using water as 

the heat transfer fluid. In addition, any new fuel burning equipment 

with a heat input capacity of 250 MMBtu/hr or more, regardless of 

whether the heat transfer fluid is water or not, would be subject to 

Vermont’s PSD program and be required to install pollution control 

equipment which meets the definition of “Most Stringent Emission 

Rate” (equivalent or better than EPA’s definition of best available 
4

(2) Reasonably available control technology for large stationary 

sources.

(a) The owner or operator of any stationary source that has 

allowable emissions of one hundred (100) tons per year 

or more of nitrogen oxides shall install, maintain and 

use reasonably available control technology, approved 

by the Secretary, to limit the discharge of nitrogen 

oxides from the source by commencement of operation.

(b) Any source that becomes or is currently subject to the 

provisions of this subsection by exceeding the 

applicability threshold in paragraph (2)(a) of this 

subsection shall remain subject to these provisions even 

if its emissions later fall below the applicability 

threshold.

(c) Exemptions. Any NOx emission unit required to meet 

the most stringent emission rate (MSER) in a 

construction permit containing specific emission limits 

is exempt from the requirements of Section 5-251(2).

control technology in 40 CFR 51.166) for SO2 and NOx emissions. This 

case-by-case analysis will result in permitted emission limits below the 

requirements of Sections 5-251(1) and 5-252.

Revisions to Section 5-252 (Control of Sulfur Dioxide Emissions)

No person shall discharge, or cause, allow or permit emissions of sulfur 

dioxide from any steam generating fuel burning equipment with a heat 

input capacity of 250 million BTU's per hour or more in excess of:

(a) 1.4 grams per million calories heat input (0.80 pounds per 

million BTU) derived from liquid fossil fuel.

(b) 2.2 grams per million calories heat input (1.2 pounds per 

million BTU) derived from solid fossil fuel.

Approve: The revisions to this section are approvable under the same 

rational articulated above for the control of nitrogen oxides in Section 

5-251.
5

Revisions to Section 5-401 (Classification of Air Contaminant Sources)

State Regulation Current SIP Regulation Action

5-401(2) Hot-mix asphalt plants Asphalt hot-mix batching plants Approve: Simple name 

change.

Revisions to 5-402 (Written Reports When Requested)

State Regulation EPA Regulation Action

5-402: The Air Pollution Control Officer may at any time require written 

reports from the person operating or responsible for any proposed or 

existing air contaminant source, which reports shall contain information 

concerning location, siting, size and height of contaminant outlets, 

processes employed, pertinent process and material flow, fuels used, 

nature and amount and time periods or durations of emissions and such 

other information as may be relevant to the air pollution potential of the 

source. These reports shall also include the results of such source testing 

as may be required under Section 5-404 herein.

Various provisions requiring submission of 

information for purposes of issuing or 

denying preconstruction permits.

Approve: Revised 

language clarifies the 

universe of sources from 

which the state has the 

authority to require 

reports.

Revisions to Section 5-406 (Required Air Modeling)

The Air Pollution Control Officer may require the owner or operator of 

any proposed air contaminant source subject to review pursuant to 

Sections 5-501 or 5-503 herein to conduct diffusion or other air quality 

modeling and to submit an air quality impact evaluation to demonstrate 

that operation of the proposed source as described to the Air Pollution 

Control Officer will not directly or indirectly result in a violation of 

any ambient air quality standard, interfere with the attainment of any 

ambient air quality standard, or violate any applicable prevention of 

significant deterioration increment (Table 2). 

(2) For proposed stationary sources, the appropriate air quality 

modeling techniques shall be determined on a case-by-case basis in 

accordance with procedures established by the Air Pollution Control 

Officer. 

40 CFR 51.160(f)(1) and 51.166(l) Approve: This SIP 

revision, when 

combined with the 

revisions Vermont 

subsequently 

promulgated to Section 

5-406, and which was

included in the State’s 

2014 SIP submittal, is 

consistent with federal 

requirements. See later 

discussion of Section 5-

406 under the section 

relating to the State’s 

2014 SIP submittal.
6

Revisions to Section 5-501 (Review of Construction or Modification of Air Contaminant Sources)

(1) No person shall cause, suffer, allow or permit the new construction, 

installation or modification of any stationary source classified as an air 

contaminant source under Section 5-401 herein, unless he or she first 

submits a complete application to and obtains a permit from the 

Secretary.

Approve: The revision 

relies on the term 

stationary source which 

is defined in the SIP as 

“any structure, building, 

facility, equipment, 

installation, or operation 

(or combination thereof) 

which emits or may emit 

any air contaminant, 

which is located on one 

or more contiguous or 

adjacent properties and 

which is owned or 

operated by the same 

person (or by persons 

under common 

control).”

Definition of stationary 

source is equivalent to 

40 CFR 51.166(b)(6).

(4) The Secretary shall issue a permit if the Secretary determines that 

the proposed construction, installation, or modification of an air 

contaminant source will be in compliance with all requirements of 

these regulations and Vermont statutes at Title 10, chapter 23. If the 

Secretary determines that the proposed construction, installation or 

modification will not be in compliance with all requirements of these 

regulations and Vermont statutes at Title 10, chapter 23, the Secretary 

shall deny the permit and shall notify the applicant in writing of the 

reasons for the denial.

51.160 (a) Each plan must set forth legally 

enforceable procedures that enable the State 

or local agency to determine whether the 

construction or modification of a facility, 

building, structure or installation, or 

combination of these will result in—

(1) A violation of applicable portions of 

the control strategy; or

(2) Interference with attainment or 

maintenance of a national standard in the 

State in which the proposed source (or 

Approve: Section 5-406 

gives the State authority 

to require a source to 

demonstrate it will not, 

violate applicable 

portions of the control 

strategy, violate a 

NAAQS, interfere with 

maintenance, or violate 

a PSD increment, using 

air dispersion modeling. 
7

modification) is located or in a neighboring 

State.

(b) Such procedures must include means by 

which the State or local agency responsible 

for final decision making on an application 

for approval to construct or modify will 

prevent such construction or modification 

if—

(1) It will result in a violation of applicable 

portions of the control strategy; or

(2) It will interfere with the attainment or 

maintenance of a national standard.

The State addresses the 

federal requirement that 

modeling be conducted 

in accordance with 

Appendix W in the 

State’s 2014 SIP 

submittal discussed later 

in this TSD. 

(7) Upon making a determination to issue a draft permit under this 

section for a major stationary source, major modification, or other 

source in the discretion of the Secretary, opportunity for public 

participation shall be provided as follows: 

* * *

(c) If required by 40 C.F.R. § 51.166(q)(2)(iv), the Secretary will send 

a copy of the notice to the applicant, EPA, and to officials and agencies 

having cognizance over the location where the proposed construction 

would occur.

40 CFR 51.166(q)(2)(iv) Approve: This 

notification obligation 

required of the State is 

an additional public 

participation provision 

that supplement the 

public notification 

provisions currently in 

the SIP and codified as 

Sections 5-501(4)(a)-(d). 

The new section 5-

501(7)(c) will not be 

replacing, but will only 

be supplementing, the 

existing SIP approved 

public participation 

requirements for major 

NSR permits.
8

Revisions to Section 5-502 (Major Stationary Sources And Major Modifications)

(2) Prohibition No person shall initiate construction of any major 

stationary source or major modification until the applicable 

requirements of this section have been complied with and a permit 

approving construction has been issued in accordance with Section 5-

501 herein.

40 CFR 51.166(a)(7)(iii) Approve: Vermont’s 

language is consistent 

with federal 

requirements.

(4) Air Quality Impact Evaluation

(a) A source or modification subject to this section with respect to any 

air contaminant other than volatile organic compounds or greenhouse 

gases, shall submit to the Secretary an air quality impact evaluation at 

the time it applies for approval to construct under Section 5-501 herein.

40 CFR 51.166(k) Approve: Although the 

provision improperly 

excludes VOCs, 

Vermont corrected this 

error in revised 

regulations submitted 

with its 2014 SIP 

submittal as explained 

later in this TSD. With 

the revision made in 

2014, Vermont’s 

language is now 

consistent with federal 

requirements.

(b) The evaluation shall demonstrate that the increase in allowable 

emissions will not cause violations of any applicable ambient air 

quality standard in any area, and will not significantly contribute to a 

violation of any applicable ambient air quality standard in a 

nonattainment area for the above air contaminants. A source or 

modification will be considered to significantly contribute to a 

violation of any ambient air quality standard for the above air 

contaminants if the increase in the allowable emissions from the source 

or modification will cause any increase in ambient concentrations of 

the above air contaminants in the nonattainment area in excess of any 

of the levels of significant impact shown in Table 3 herein. If a source 

or modification will significantly contribute to such a violation, the 

40 CFR 51.166(k)(1)(i) and 51.165(b)(2): Approve: This SIP 

revision, when 

combined with the 

revisions Vermont 

subsequently 

promulgated to Section 

5-502(4)(b), and which 

was included in the 

State’s 2014 SIP 

submittal, is consistent

with federal 

requirements. See later 
9

evaluation shall demonstrate that the source or modification will 

comply with the requirements of paragraph (6) herein.

discussion of Section 5-

502(4)(b) under the 

section relating to the 

State’s 2014 SIP 

submittal.

(e) Any air quality impact evaluation or modeling required by this 

section shall be prepared in accordance with procedures acceptable to 

the Secretary and with Section 5-406 of these regulations. The 

evaluation shall exclude the effect of that portion of the height of any 

stack which exceeds good engineering practice and the effect of any 

other dispersion technique.

40 CFR 51.166(l) Approve: The revision

to Section 5-406 of the 

State’s regulations, 

submitted by the State 

with its 2014 SIP 

submittal, requires 

modeling to be 

conducted in accordance 

with 40 CFR part 51, 

Appendix W, and 

therefore meets federal 

requirements.

(6)(b) Regardless of whether a source or modification is subject to the

requirements of paragraph (6)(a) of this section, the Secretary shall not 

issue a permit approving construction of any source or modification of 

nitrogen oxides or volatile organic compounds (VOCs) subject to this 

section and meeting the federal definition of major stationary source or 

major modification contained in 40 CFR Part 51.165 as applicable to 

the Ozone Transport Region unless, prior to issuance of such permit, 

the owner or operator of said source shall:

(i) Secure legally binding offsetting emission reductions (not otherwise 

required by law) of nitrogen oxides or VOCs, as applicable, from 

existing sources;

(ii) Obtain an offset ratio of a minimum of 1.15:1; and

40 CFR 51.165 Approve: Vermont’s 

revised language makes 

it clear that 

nonattainment new 

source review applies to 

major sources of NOx 

and VOC in relation to 

ozone, because Vermont 

is located in the Ozone 

Transport Region. The 

2014 SIP submittal 

made a slight revision to 

this provision by 

replacing “Part” with 

“§” when citing 40 CFR 

51.165.
10

(iii) Certify that all existing sources of the source owner located in the 

state are subject to emissions limitations and are in compliance, or on 

an enforceable schedule for compliance with all applicable emissions 

limitations and standards.

(8) Ambient Air Quality Monitoring

(b) Ambient monitoring data shall be based on sampling conducted for

a time period of up to one year immediately preceding submission of 

any application for approval to construct such a source or modification. 

Ambient monitoring data collected for a time period of less than one 

year or for a time period other than immediately preceding submission 

of any such application may be acceptable if such data is adequate for 

determining whether the source or modification will cause a violation 

of any applicable ambient air quality standard or consume more than 

the remaining available PSD increment.

40 CFR 51.166(m)(1)(b)(iii) and (iv) Approve: The State’s 

provision submitted in 

the State’s 2011 SIP 

submission, when 

combined with the 

revisions to the 

provision Vermont 

subsequently made and 

submitted to EPA in 

2014, is consistent with 

EPA regulations.
11

2014

July 25, 2014 SIP Submittal

Revisions to Section 5-101 (Definitions)

State Definition EPA Regulation Action

“Municipal Waste Combustor Acid Gases (measured 

as sulfur dioxide and hydrogen chloride)” means all 

acid gases emitted in the exhaust gases from MWC 

units including, but not limited to, sulfur dioxide and 

hydrogen chloride gases.

40 CFR 51.166(b)(23)(i): Municipal waste combustor acid 

gases (measured as sulfur dioxide and hydrogen chloride): 36 

megagrams per year (40 tons per year)

40 CFR 60.51(a): MWC acid gases means all acid gases 

emitted in the exhaust gases from MWC units including, but 

not limited to, sulfur dioxide and hydrogen chloride gases. 

Approve: Vermont’s 

language is consistent 

with federal regulations.

“Municipal Waste Combustor Metals (measured as 

particulate matter)” means metals and metal 

compounds emitted in the exhaust gases from MWC 

units.

40 40 CFR 51.166(b)(23)(i): Municipal waste combustor 

metals (measured as particulate matter): 14 megagrams per 

year (15 tons per year)

40 CFR 60.51(a): MWC metals means metals and metal 

compounds emitted in the exhaust gases from MWC units. 

Approve: Vermont’s 

language is consistent 

with federal regulations.

“Municipal Waste Combustor Organics (measured 

as total tetra- through octa- chlorinated dibenzo-pdioxins and dibenzofurans)” means organic 

compounds emitted in the exhaust gases from MWC 

units and includes total tetra- through octachlorinated dibenzo-p-dioxins and dibenzofurans.

40 CFR 51.166(b)(23)(i): Municipal waste combustor acid 

gases (measured as sulfur dioxide and hydrogen chloride): 36 

megagrams per year (40 tons per year)

40 CFR 60.51(a): MWC organics means organic compounds 

emitted in the exhaust gases from MWC units and includes 

total tetra- through octa-chlorinated dibenzo-p-dioxins and 

dibenzofurans.

Approve: Vermont’s 

language is consistent 

with federal regulations.

“Municipal Solid Waste Landfill Emissions

(measured as nonmethane organic compounds)”

means gas generated by the decomposition of 

organic waste deposited in an MSW landfill or 

40 CFR 51.166(b)(23)(i): Municipal solid waste landfill 

emissions (measured as nonmethane organic compounds): 45 

megagrams per year (50 tons per year)

Approve: Vermont’s 

language is consistent 

with federal regulations.
12

derived from the evolution of organic compounds in 

the waste.

40 CFR 60.751: Municipal solid waste landfill emissions or 

MSW landfill emissions means gas generated by the 

decomposition of organic waste deposited in an MSW landfill 

or derived from the evolution of organic compounds in the 

waste.

“Particulate Matter” means any airborne finely 

divided solid or liquid material with an aerodynamic 

diameter smaller than one-hundred (100) 

micrometers.

40 CFR part 51 Approve: Vermont’s 

language is consistent 

with federal regulations.

“Particulate Matter Emissions” means all finely 

divided solid or liquid material, other than 

uncombined water, emitted to the ambient air as 

measured by applicable reference methods, or an 

equivalent or alternative method, specified in 40 

C.F.R. Chapter 1. Emissions shall include gaseous 

emissions from a source or activity which condense 

to form particulate matter at ambient temperatures.

40 CFR 51.50: Particulate matter (PM) is a criteria air 

pollutant. For the purpose of this subpart, the following 

definitions apply:

(1) Filterable PM2.5 or Filterable PM10: Particles that are 

directly emitted by a source as a solid or liquid at stack or 

release conditions and captured on the filter of a stack test 

train. Filterable PM2.5 is particulate matter with an 

aerodynamic diameter equal to or less than 2.5 micrometers. 

Filterable PM10 is particulate matter with an aerodynamic 

diameter equal to or less than 10 micrometers.

(2) Condensable PM: Material that is vapor phase at stack 

conditions, but which condenses and/or reacts upon cooling 

and dilution in the ambient air to form solid or liquid PM 

immediately after discharge from the stack. Note that all 

condensable PM, if present from a source, is typically in the 

PM2.5 size fraction and, therefore, all of it is a component of 

both primary PM2.5 and primary PM10.

(3) Primary PM2.5: The sum of filterable PM2.5 and 

condensable PM.

(4) Primary PM10: The sum of filterable PM10 and 

condensable PM.

Approve: Vermont’s 

language is consistent 

with federal regulations.
13

(5) Secondary PM: Particles that form or grow in mass through 

chemical reactions in the ambient air well after dilution and 

condensation have occurred. Secondary PM is usually formed 

at some distance downwind from the source. Secondary PM 

should not be reported in the emission inventory and is not 

covered by this subpart.

“PM10” means particulate matter with an 

aerodynamic diameter less than or equal to a 

nominal ten (10) micrometers as measured by a 

reference method based on appendix J of 40 C.F.R. 

Part 50 and designated in accordance with 40 C.F.R. 

Part 53, or by an equivalent method designated in 

accordance with 40 C.F.R. Part 53. 

40 CFR part 51 Approve: Vermont’s 

language is consistent 

with federal regulations.

“PM10 Emissions” means finely divided solid or 

liquid material, with an aerodynamic diameter less 

than or equal to a nominal ten (10) micrometers 

emitted to the ambient air as measured by an 

applicable reference method, or an equivalent or 

alternative method, specified in 40 C.F.R. Chapter 1. 

Emissions shall include gaseous emissions from a 

source or activity which condense to form 

particulate matter at ambient temperatures. 

40 CFR part 51 Approve: Vermont’s 

language is consistent 

with federal regulations.

“PM2.5” means particulate matter with an 

aerodynamic diameter less than or equal to a 

nominal two-and-a-half (2.5) micrometers as 

measured by a reference method based on Appendix 

L of 40 C.F.R. Part 50 and designated in accordance 

with 40 C.F.R. Part 53, or by an equivalent method 

designated in accordance with 40 C.F.R. Part 53.

40 CFR part 51 Approve: Vermont’s 

language is consistent 

with federal regulations.

“PM2.5 direct emissions” means finely divided solid 

or liquid material, with an aerodynamic diameter 

less than or equal to a nominal two-and-a-half (2.5) 

micrometers emitted to the ambient air as measured 

40 CFR part 51 Approve: Vermont’s 

language is consistent 

with federal regulations.
14

by an applicable reference method, or an equivalent 

or alternative method, specified in 40 C.F.R. 

Chapter 1. Emissions shall include gaseous 

emissions from a source or activity which condense 

to form particulate matter at ambient temperatures.

It does not include emissions of other gaseous 

precursors which may subsequently contribute to 

formation of secondary PM2.5 particles through 

chemical reactions. 
15

Air Contaminant Tons Per Year

Carbon monoxide 50

Nitrogen oxides 40

Sulfur dioxide 40

Particulate matter emissions 25

PM10 emissions 15

PM2.5

1

 PM2.5 direct emissions 10

 Sulfur dioxide 40

 Nitrogen oxides 40

Volatile organic 

compounds(VOC) 40

Lead 0.6

Fluorides 3

Sulfuric acid mist 7

Hydrogen sulfide (H2S) 10

Total reduced sulfur 

(including H2S) 10

Reduced sulfur compounds 

(including H2S) 10

Municipal waste combustor 

organics (measured

as total tetra-through octachlorinated

dibenzo-p-dioxins and

3.5 × 10-6

40 CFR 51.166(b)(23) Approve: The 

highlighted text is the 

revised text contained in 

the State’s 2014 SIP 

revision and is 

consistent with EPA’s 

regulations.
16

dibenzofurans)

Municipal waste combustor 

metals (measured

as particulate matter)

15

Municipal waste combustor 

acid gases

(measured as sulfur dioxide 

and hydrogen

chloride)

40

Municipal solid waste landfill 

emissions

(measured as nonmethane 

organic compounds)

50

Greenhouse gases 1. 2

1 For PM2.5, significant means either 10 tons per 

year or more of direct PM2.5 emissions, 40 

tons per year or more of sulfur dioxide 

emissions or 40 tons per year or more of 

nitrogen oxides emissions.

2For greenhouse gases, “significant” means a rate 

of emissions for total greenhouse gases, on a 

carbon dioxide equivalent (CO2e) basis, that 

(1) is subject to regulation at that source or 

modification, and (2) would equal or exceed 

the significance level established by EPA.
17

Revision to Section 5-253.20 (Other Sources That Emit Volatile Organic Compounds)

Revision to the State Regulation EPA Regulation Action

Vermont requested removing the exemption for 

wood coating from applicability section in Section 

5-253.20(a)(3).

Approve: This revision 

means that wood coating 

operations are now 

subject to the section 

limiting emissions from 

miscellaneous VOC 

sources in the Vermont 

SIP, and is consistent 

with Clean Air Act and 

State requirements for 

controlling VOC 

emissions.
18

Revisions to Subchapter III (Ambient Air Quality Standards)

State Regulation EPA Regulation Action

5-301 SCOPE

The ambient air quality standards contained in this subchapter are based on national 

ambient air quality standards, with the exception of sulfates which are a state 

standard only. The primary standards define levels of air quality judged adequate 

to protect the public health. The secondary standards define levels of air quality 

judged adequate to protect the public welfare, to prevent injury to animal or 

plant life or property, and to prevent unreasonable interference with the 

enjoyment of life or property.

40 CFR Part 50 Approve: Vermont’s 

language is consistent 

with federal regulations. 

5-302 SULFUR OXIDES (SULFUR DIOXIDE) 

The ambient air quality standards for sulfur oxides, measured as sulfur dioxide in 

accordance with 40 C.F.R. Part 50, are: 

75 parts per billion (ppb), with a 1-hour averaging time and a form of the 99th 

percentile of 1-hour daily maximum concentrations, averaged over 3 years 

(Primary Standard).

0.5 parts per million (ppm), with a 3-hour averaging time and a form that is not to be 

exceeded more than once per year (Secondary Standard).

40 CFR Part 50 Approve: Vermont’s 

language is consistent 

with federal regulations. 

5-303 RESERVED
19

5-304 PARTICULATE MATTER PM2.5

The ambient air quality standards for particulate matter PM2.5, measured in 

accordance with 40 C.F.R. Part 50, are: 

35 micrograms per cubic meter (μg/m3), with a 24-hour averaging time and a 

form of the 98th percentile, averaged over 3 years (Primary and Secondary 

Standard).

12 micrograms per cubic meter (μg/m3), with an annual averaging time and a 

form of the annual mean averaged over 3 years (Primary Standard).

15 micrograms per cubic meter (μg/m3), with an annual averaging time and a 

form of the annual mean averaged over 3 years (Secondary Standard).

40 CFR Part 50 Approve: Vermont’s 

language is consistent 

with federal regulations. 

5-305 RESERVED
20

5-306 PARTICULATE MATTER PM10

The ambient air quality standards for particulate matter PM10, measured in 

accordance with 40 C.F.R. Part 50, are:

150 micrograms per cubic meter (μg/m3), with a 24-hour averaging time and a 

form not to be exceeded more than once per year on average over 3 years 

(Primary and Secondary Standard).

40 CFR Part 50 Approve: Vermont’s 

language is consistent 

with federal regulations. 

5-307 CARBON MONOXIDE 

The ambient air quality standards for carbon monoxide, measured in accordance 

with 40 C.F.R. Part 50, are: 

35 parts per million (ppm), with a 1-hour averaging time and a form not to be 

exceeded more than once per year (Primary Standard).

9 parts per million (ppm), with an 8-hour averaging time and a form not to be 

exceeded more than once per year (Primary Standard).

40 CFR Part 50 Approve: Vermont’s 

language is consistent 

with federal regulations. 
21

5-308 OZONE 

The ambient air quality standards for ozone, measured in accordance with 40 

C.F.R. Part 50, are: 

0.075 parts per million (ppm), with an 8-hour averaging time and a form of the 

annual fourth-highest daily maximum 8-hour concentration, averaged over 3 

years (Primary and Secondary Standard).

40 CFR Part 50 Approve: Vermont’s 

language is consistent 

with the federal 2008 

ozone standard. Because 

the State last revised this 

section of its rules in 

2014, the State was 

unable at that time to 

address the 2015 ozone 

standard, which had not 

yet been promulgated by 

EPA. Therefore, while 

the provision is 

approvable because the 

2008 ozone standard has 

not been revoked by

EPA, the approval is not 

suggesting the State’s 

provision is adequate to 

reflect the federal 2015 

ozone standard. The 

State is expected to 

address this new ozone 

standard in a subsequent 

submittal to EPA.
22

5-309 NITROGEN DIOXIDE 

The ambient air quality standards for nitrogen dioxide, measured in accordance 

with 40 C.F.R. Part 50, are: 

100 parts per billion (ppb), with a 1 hour averaging time, and a form of the 98th

percentile, averaged over 3 years (Primary Standard).

53 parts per billion (ppb), with an annual averaging time, and a form of the 

annual mean (Primary and Secondary Standard).

40 CFR Part 50 Approve: Vermont’s 

language is consistent 

with federal regulations. 

5-310 LEAD 

The ambient air quality standards for lead and its compounds, measured in 

accordance with 40 C.F.R. Part 50, are: 

0.15 micrograms per cubic meter (μg/m3), with a rolling 3-month average 

averaging time and a not-to-be-exceeded form, evaluated over a 3-year 

period (Primary and Secondary Standard).

40 CFR Part 50 Approve: Vermont’s 

language is consistent 

with federal regulations. 

Revisions to Section 5-406 Required Air Modeling

State Regulation EPA Regulation Action

(1) The Air Pollution Control Officer may require the owner or operator of any 

proposed air contaminant source subject to review pursuant to Section 5-501 herein 

to conduct dispersion or other air quality modeling and to submit an air quality 

impact evaluation to demonstrate that operation of the proposed source as described 

to the Air Pollution Control Officer will not directly or indirectly result in a 

violation of any ambient air quality standard, interfere with the attainment of any 

ambient air quality standard, or violate any applicable prevention of significant 

deterioration increment (Table 2).

(2) For proposed stationary sources, the appropriate air quality modeling techniques 

shall be determined on a case-by-case basis in accordance with procedures 

established in 40 C.F.R. Part 51 Appendix W.

40 CFR 51.160(f) and 

51.166(l). 

Approve: Vermont’s 

language is consistent 

with federal regulations.
23

Revisions to Section 5-501 (Review of New Air Contaminant Sources)

State Regulation Existing SIP Approved 

Language

Action

(5) Section 5-501(5): If allowable emission increases of any air contaminant from a 

source subject to this section will cause or contribute to a violation of any ambient 

air quality standard or cause or contribute to a violation of any applicable 

prevention of significant deterioration increment (Table 2), or if such source is 

located within 10 kilometers of a Class I area and will have an impact on such Class 

I area of equal to or greater than 1 ug/m3(24-hour average) for any air 

contaminant, such air contaminant shall be considered significant and such source 

will be treated as a major stationary source or a major modification for the purposes 

of its review under these regulations. With regard to a modification of a source, the 

allowable emission increases mean the difference between the source's actual 

emissions before the modification and its allowable emissions after the modification.

(5) If allowable emission 

increases of any air 

contaminant from a source 

subject to this section will 

cause or contribute to a 

violation of any ambient air 

quality standard or cause or 

contribute to a violation of any 

applicable prevention of 

significant deterioration 

increment (Table 2), or will 

impact on any Class I area, 

such source shall achieve 

MSER with respect to any 

such contaminant and will be 

treated as a major stationary 

source or a major modification 

for the purposes of its review 

under these regulations. With 

regard to a modification of a 

source, the allowable emission 

increases mean the difference 

between the source's actual 

emissions before the 

modification and its allowable 

emissions after the 

modification. 

Approve: This section of 

Vermont’s regulations 

require sources that 

would only be subject to 

minor new source 

review to obtain a major 

new source review if the 

State determines that the 

impacts from the new 

source meet the criteria 

specified in section 5-

501(5). There is no 

corresponding federal 

regulation, but this 

provision is approvable 

because States are 

permitted to be more 

stringent than the federal 

regulations.
24

State Regulation EPA Regulation Action

(7) Upon making a determination to issue a draft permit under this section for a major 

stationary source, major modification, or other source in the discretion of the 

Secretary, opportunity for public participation shall be provided as follows:

* * * 

(c) If required by 40 C.F.R. §51.166(q)(2)(iv), the Secretary will send a copy of 

the notice to the applicant, the EPA Regional Administrator, and to officials and 

agencies having cognizance over the location where the proposed construction 

would occur, including: any other State or local air pollution control agencies, 

the chief executives of the city or town and county where the source would be 

located, any comprehensive regional land use planning agency, and any State, 

Federal Land Manager, or Indian Governing body whose lands may be affected 

by emissions from the source or modification.

40 CFR 51.166(q)(2)(iv): Approve: State language 

is consistent with EPA’s 

regulations. See earlier 

discussion in this TSD 

regarding how this 

provision meshes with 

already existing SIPapproved public 

participation 

requirements for major 

sources. 

Revisions to Section 5-502 (Major Stationary Source and Major Modification)

State Regulation EPA Regulation Action

Section 5-502(4)(a) Air Quality Impact Evaluation

(a) A source or modification subject to this section with respect to any air 

contaminant other than greenhouse gases, shall submit to the Secretary an air 

quality impact evaluation at the time it applies for approval to construct under 

Section 5-501 herein.

40 CFR 51.166(k) Approve: State language 

is consistent with EPA’s 

regulations. See earlier 

discussion in this TSD 

regarding the same 

provision submitted 

earlier by the State to 

EPA. The earlier 

exclusion of VOCs from 

this provision is 

corrected in this version 

of the provision. 

Section 5-502(4)(b): Ambient Air Quality Standards review: 

The evaluation shall demonstrate that the increase in allowable emissions will not 

cause a violation of any applicable ambient air quality standard in any area, and 

will not significantly contribute to a violation of any applicable ambient air quality 

40 CFR 51.166(k) and 

51.165(b) 

Approve: State language 

is consistent with EPA’s 

regulations. See earlier 

discussion in this TSD 
25

standard in any area that does not or would not meet the applicable ambient air 

quality standard for the above air contaminants. A source or modification will be 

considered to significantly contribute to, a violation of any ambient air quality 

standard for the above air contaminants if the increase in the allowable emissions

from the source or modification will cause an increase in ambient concentrations of 

the above air contaminants in any area that does not or would not meet the 

applicable ambient air quality standard in excess of any of the levels of significant 

impact shown in Table 3 herein. If a source or modification will significantly 

contribute to such a violation, the evaluation shall demonstrate that the source or 

modification will comply with the requirements of paragraph (6) herein.

regarding the same 

provision submitted 

earlier by the State to 

EPA. This section in the 

2011 SIP submittal was 

applicable to a source if 

the source’s emissions 

significantly contributed 

to a violation in a 

designated 

nonattainment areas. In 

2014, the State revised 

its rule to include any 

area that is violating a 

standard, whether or not 

that area has been 

formerly designated a 

nonattainment area by 

EPA.

Section 5-502(4)(e) Class I Federal Area review: The evaluation shall demonstrate 

that the increase in allowable emissions will not cause an adverse impact on 

visibility or any other Air Quality Related Value in any Class I Federal area. 

40 CFR 51.166(p) Approve: State language 

is consistent with EPA’s 

regulations.

Section 5-502(6)(b) 40 CFR 51.165 Approve: State language 

is consistent with EPA’s 

regulations. See earlier 

discussion in this TSD 

regarding the same 

provision submitted 

earlier by the State to 

EPA. The revision 

Vermont made to this 
26

provision in 2014 

replaced the word “part” 

with § when citing 40 

CFR §51.166.

Section 5-502(8)(b): Ambient monitoring data shall be based on sampling conducted 

for a time period of at least one year immediately preceding submission of any 

application for approval to construct such a source or modification. Ambient 

monitoring data collected for a time period of less than one year, but not less than 

four (4) months, or for a time period other than immediately preceding submission 

of any such application may be acceptable if such data is adequate for determining 

whether the source or modification will cause a violation of any applicable ambient 

air quality standard or consume more than the remaining available PSD increment.

40 CFR 51.166(m)(1)(iv) Approve: State language 

is consistent with EPA’s 

regulations. See earlier 

discussion in this TSD 

regarding the same 

provision submitted 

earlier by the State to 

EPA. The revisions 

Vermont made to this 

provision in 2014 clarify

that a minimum of 4 

months of monitoring 

data is required in all 

circumstances.