RESPONSE TO COMMENTS 

MassDEP issued for public review and comment the proposed Massachusetts State 

Implementation Plan (SIP) to Demonstrate Attainment of the National Ambient Air Quality 

Standard for Ozone (Ozone SIP). The substantive comments received, and MassDEP's 

responses thereto, are discussed below. In addition to substantive comments, the U.S . EPA 

noted typographical errors or suggested points of clarification . Minor corrections and 

clarifications are addressed in the final Ozone SIP submitted to EPA, but are not discussed 

below. 

Commenters: 

1 . U.S . Environmental Protection Agency, Region 1 

comments dated: December 27, 2007; January 17, 2008; January 28, 2008 

2. Associated Industries of Massachusetts 

3 . General Electric 

4. St. Gobain Abrasives, Inc . 

5 . Bob Machaver 

Summary of Comments Received and MassDEP Responses 

EPA comments regarding Reasonable Further Progress (Comments #2, 3 - 12/27/07) 

MassDEP should include the source of the growth factors for commercial marine and locomotive 

emission projections. 

The last step shown in Table RFP 3 (line #8) should be revised or eliminated . Since the 

baselines from which the combined reductions were calculated are different, combining the 

percentages gives a somewhat inaccurate result . 

Response: 

The growth factor for commercial marine and locomotive sources has been added in Section 4.5 . 

The last calculation in Table RFP 3 has been deleted. 

EPA comments regarding control measures (Comments # 1, #17, #18 - 1/17/08) 

MassDEP should include a commitment to submit the regulations listed in Table CM 1 (Section 

3, Control Measures) to EPA as a State Implementation Plan (SIP) revision by a date certain. 

When MassDEP submits the SIP revision for the revised enhanced inspection and maintenance 

(I/M) program, it should demonstrate that its revised I/M program effectively replaces the 

emission reductions required by the existing program, as well as meets the requirements of 
EPA's I/M rule . MassDEP should also provide a date for submittal of its power plant regulation, 

310 CMR 7.29, (discussed in Section 6, Reasonably Available Control Technology (RACT)) as a 

SIP revision. 

Response: 

In the final SIP, MassDEP has added a column to Table CM 1 of Section 3 to include the date by 

which it intends to submit the listed regulations to EPA as SIP amendments. The separate I/M 

SIP amendment that MassDEP will submit for the revised I/M program will demonstrate that the 

revised program effectively replaces the emission reductions achieved by the existing program, 

and will meet the requirements of EPA's I&M rule . The NOx provisions of Massachusetts power 

plan regulation, 310 CMR 7.29, will be submitted to EPA as a SIP revision by March 1, 2008 ; 

this is noted in Section 6, RACT (page 10). 

EPA comment regarding emission reductions (Comment #3 - 1/17/08) 

Footnote #7 to Table CM 3, which provides emission reduction estimates for new post -2002 

area source control measures, states that the estimates for the area source measures are based on 

the combined analysis of MassDEP and MACTEC (Appendix 5K, Identification and Evaluation 

of Candidate Control Measures: Final Technical Support Document, MACTEC, February 28, 

2007), as part of the OTC regional ozone attainment planning process. The estimates in Table 

CM 3 appear to differ from the estimates in Appendix K. MassDEP should explain how these 

estimates were developed, or reference a specific location in the appendices where this is 

discussed. 

Response: 

MassDEP has revised Table CM 3 to make the estimated emission benefits consistent with the 

estimates in Appendix 5K, Identification and Evaluation of Candidate Control Measures: Final 

Technical Support Document; that document was developed by MACTEC for the OTC, with 

input from the OTC states . The benefits estimated for 2009 in the earlier version of Table CM 3 

in the proposed Ozone SIP were calculated using the 2002 base year emissions. The revised 

Table CM3, consistent with Appendix 5K, estimates the reductions benefits of the control 

measures listed by comparing base 2009 emissions with 2009 controlled emissions for each post2002 control measure. 

Also, Appendix K does not discuss the two area source categories of solvent cleaning and 

architectural and industrial maintenance (AIM) coatings . These are post-2002 measures for 

Massachusetts and are, therefore, listed in Table CM3. These were not measures recommended 

for adoption by the OTC in 2006, so are not included in Appendix 5K. 

EPA comments regarding anti-back-sliding (Comment #4 - 1/17/08) 

The discussion of the 1-hour ozone standard control measures (Appendix 3A) concerning New 

Source Review should be revised to reflect the Phase I court ruling on anti-backsliding, which 
requires Massachusetts to maintain the 50 ton per year threshold for VOC and NOx and a 1 .2- to1 offset ratio based on its "serious" classification under the one-hour ozone standard . 

Response: 

MassDEP has revised this discussion to reflect that the court set aside the provisions of EPA's 

Phase I Rule that would have permitted backsliding. (MassDEP decided to retain the 50 tons per 

year threshold for VOC and NOx 1 .2- to-1 offset ratio even prior to the court decision .) 

EPA comment regarding 1-hour ozone standard (Comment # 6 - 1/17/08) 

The statement (Section 1 .3, Page 3) that both EMA and WMA had monitored readings that met 

the 1-hour ozone standard for 2004-2006 is incorrect. The Chicopee monitor in WMA exceeded 

the 1-hour ozone standard during the 2004-2006 period. 

Response: 

MassDEP has deleted this statement, which it agrees was inaccurate for WMA. Only EMA met 

the now-revoked 1-hour standard for the 2004-2006 period. 

EPA comment regarding extension of attainment date (Comments #5, #7 - 1/17/08) 

EPA suggests revisions to the discussion in Section 1 .1 that relates to the criteria for 

Massachusetts to seek an extension of the 2009 attainment year if either EMA or WMA fail to 

attain the standard by the 2009 attainment year. 

Response; 

MassDEP has revised the discussion to clarify the criteria under which Massachusetts may seek a 

1-year extension of the 2009 attainment date. 

EPA comment regarding trends data (comment #9, 1-17-08) 

The "Air Quality Trends" section (Section 5.19.1, page 33) presents graphs of design value 

trends for EMA and WMA and states that the trends suggest that EMA and WMA are on track to 

meet the ozone standard by 2009. EPA does not agree that the trend line for the WMA design 

values shows it to be on track to meet 84 parts per billion (ppb) by 2009. The discussion in the 

introduction (Section 1 .5, Page 5) seems to present a more realistic interpretation of the status of 

the WMA. 

Response: 

MassDEP agrees that while the trend data for EMA clearly shows it to be on track to attain in 

2009, there is no clear trend for WMA data. MassDEP has revised the discussion to state that 

based upon ozone modeling results, ozone air quality trends and ozone precursor trends, 
MassDEP expects that EMA will attain the 8-hour ozone NAAQS by 2009, and that, while 

WMA may attain by 2009, if it does not, it will be eligible for a 1-year extension of the 2009 

attainment date . 

EPA comments regarding 2007 ozone episodes (comment #10 - 1/17/08) 

The discussion of high ozone concentrations in WMA on August 3 and August 30, 2007 (Section 

5 .19 .5) never comes to a conclusion as to the significance of these two days. If the smoke did 

interfere with the measurement of ozone or caused enhanced ozone production on these days, 

then absent the smoke, what would the resulting 4th high ozone concentration be for the key sites 

of Chicopee and Ware? How would this effect design values and ozone trends? Is the smoke a 

regular occurrence, or is it a unique circumstance that might rise to the level of an "exceptional 

event" following EPA guidance? How do these two days impact the conclusions presented at the 

end of Section 5 (specifically, Section 5.20, page 48-49)? 

Response: 

These high monitored ozone readings in Chicopee 2007 (August 3 - 3rd highest of 103 ppb) and 

(August 30 - 4th highest of 98 ppb) were discussed to illustrate the unusual nature of these 

concentrations and to identify factors that likely contributed to these high concentrations, 

specifically, meteorological conditions and smoke. These contributing factors support 

MassDEP's view that the readings in 2007 were unusually high and that MassDEP can 

reasonably anticipate that the Chicopee monitor will have a 4a' high reading of 84 ppb or less in 

2009. This would satisfy the eligibility requirements for a 1-year extension of attainment year in 

2009 for WMA. 

EPA Comment Regarding Regional Ozone Attainment Modeling (1-28-08) 

MassDEP should provide detailed daily emission files by state, source sector and time of year for 

2002 ozone episodes. EPA Region I analysis indicates that actual hourly emission files for the 

electric generating sector in 2002 are higher than some CMAQ hourly emission files, and that 

implies that future year emissions and ozone levels may be underestimated. 

Response: 

The 2002 and 2009 ozone precursor emission inputs (pre-SMOKE and post-SMOKE processed 

files) used for the CMAQ SIP modeling runs are available in electronic format upon request to 

NYS DEC. MassDEP does not presently have the resources to construct the daily 2002 and 

2009 emission files requested, and recommends that EPA contact the NYS DEC, which served 

as the lead OTC Modeling Center, to see if detailed daily emission files by state, source sector 

and time of year can be extracted from CMAQ input files. It is not clear that inspection of these 

daily emission files is needed to determine if the EGU control program is being accurately 

quantified in the CMAQ SIP-quality modeling runs. Future year EGU emission inventory 

documentation is contained in Appendix 5M to Section 5, Attainment Demonstration. 
The CMAQ SIP-quality modeling runs performed on behalf of the OTC (and used by MassDEP) 

did not incorporate daily variations in EGU emissions associated with weather-induced 

electricity demand. The OTC approach was to use the SMOKE model to apportion annual 

emissions (based on annual CEM data) provided by the states in order to prepare consistent 

emission files using month-of-year, day-of-week, and hour-of-day temporal profiles. No 

adjustments for ozone or non-ozone episodes were attempted; none of the control strategies are 

day-specific or aimed specifically at high ozone episodes. 

MassDEP recognizes that on some days actual hourly emissions may be higher than CMAQ 

model run emissions and that on other days actual hourly emissions may be lower than CMAQ 

model run emissions. However, using the CMAQ model in a relative way (as recommended by 

EPA guidance) helps minimize the effects of any under-estimated or over-estimated emissions in 

the base case (2002) that are grown out to and controlled in the future case (2009) . 

Future case emissions projections for the energy sector were estimated using the IPM model 

which was considered to be the best available tool at the time the OTC CMAQ SIP-quality 

modeling runs were performed (2006) . The IPM model produced summer season and annual 

emissions, reflecting the CAIR program, the national control strategy for this sector . For 

consistency, the same month-of-year, day-of-week, and hour-of-day temporal profiles used to 

prepare 2002 hourly emission files were also used to prepare 2009 hourly emission files. To 

apply temporal files based upon actual 2002 hourly emission rates was considered to be 

guesswork since IPM does not assume that the same sources in 2002 would be operating in the 

same way in future-case years. 

In summary, MassDEP believes that the use of consistent temporal files for 2002 and 2009 and 

using the CMAQ model in a relative way (calculating the percent reduction in ozone levels 

instead of using the actual predicted 2009 ozone levels) is the most appropriate way of assessing 

the effectiveness of ozone control strategies in the OTC at this time. The 2002 and 2009 ozone 

precursor emission inputs (pre-SMOKE and post-SMOKE processed files) used for the CMAQ 

SIP modeling runs are available in electronic form upon request to NYS DEC (contact Gopal 

Sistla at gsistla@dec.state .ny.us) . 

Comments regarding Reasonably Available Control Technology (RACT) 

EPA Comment on Municipal Waste Combustors (MWCs) RACT (Comment #15 - 1/17/08) 

The NOx RACT section does not contain an analysis of whether the current limits in 

Massachusetts represent RACT in light of more stringent limits adopted by other states . For 

example, the NOx emission limits found within Connecticut's MWC regulation are more 

stringent than the Massachusetts limits . EPA recommends that Massachusetts consider adopting 

limits similar to those adopted by Connecticut. 
Response: 

MassDEP will re-examine whether its current MACT regulations for MWC, 310 CMR 7.08 (2), 

still constitute RACT for MWCs in light of this comment. By April 1, 2008, it commits to do an 

additional analysis on whether it is cost effective to further reduce NOx emissions from existing 

MWCs. MassDEP will include stakeholders (i .e . the MWCs, municipalities, and environmental 

organizations) as part of this process. 

MassDEP expects to propose revisions to its MWC regulations by December 31, 2008 to comply 

with the U.S . EPA's Standards of Performance for New Stationary Sources and Emission 

Guidelines for Existing Stationary Sources: Large Municipal Waste Combustors, 40 CFR 60 

subpart Cb. Based on the findings of the additional RACT analysis, MassDEP will consider 

whether to include a proposal for more stringent NOx limits when it proposes the revisions to the 

Massachusetts Municipal Waste Combustor Regulations. 

EPA Comment on Glass Manufacturing RACT (Comment # 19 -1/17/08) 

Table RACT-1 indicates that Massachusetts believes its existing NOx RACT rule is sufficient to 

meet RACT for the glass-manufacturing category. Glass manufacturing is one of the 2006 OTC 

recommended categories for additional control. MassDEP should document that the one large 

glass manufacturing facility Massachusetts, Saint Gobain Containers (located in Milford), is 

currently subject to emission limits that are as stringent as those found in the OTC 2006 

recommended control measure for this sector . 

Response: 

Since 2001, St. Gobain Containers' average NOx emissions have been 3 .38 pounds/ton of glass 

pulled, based on stack testing. These annual stack testing data demonstrate that St. Gobain 

Containers' actual NOx emission rates from its glass manufacturing process are below the 

recommended OTC NOx limit for this category. Documentation is available for review. 

Comments on Industrial, Commercial and Institutional Boiler RACT: 

EPA (Comments # 14, #15, #19 - 1-17-08) : 

EPA recommends that MassDEP consider adopting more stringent regulations for industrial, 

commercial, and institutional (ICI) boilers as part of meeting Massachusetts NOx RACT 

obligation. Further regulation of this sector is one of the control options that the Ozone Transport 

Commission (OTC) states agreed to explore, as discussed in Appendix 5K, which includes 

recommended emission limits . The Mass DEP NOx RACT analysis in Section 6.5 does not 

include any discussion of consideration of this measure. 
Industry Comments: 

Associated Industries of Massachusetts (AIM) Comment: 

AIM supports MassDEP's conclusion with respect to the adequacy of RACT for ICI boilers, 

noting that the sources that would be covered by any tighter RACT restrictions for this category 

represent some of the most vulnerable and cost-sensitive companies in the state. 

St. Gobain Abrasives, Inc. Comment: 

The commenter is concerned about the impact of added compliance costs and resubmitted its 

May 31, 2006 letter to MassDEP. That letter estimated the high costs of installing Selective 

Catalytic or Selective Non-Catalytic Reduction to its existing boiler and the estimated range of 

costs per ton of NOx reductions . 

General Electric Comment: 

The commenter supports MassDEP's conclusion that current RACT satisfied 8-hour ozone 

standard RACT requirements for ICI boilers. It resubmitted its 8-page May 2006 preliminary 

assessment of the technological feasibility and estimated costs of additional NOx controls at its 

Lynn facility. 

Bob Machaver Comment: 

The commenter agrees that current NOx RACT levels are technically and regulatorily justified, 

and that an additional reason why it is not appropriate to enhance the stringency of NOx RACT, 

is that two major stationary source programs will begin in 2009 : the Clean Air Interstate Rule 

(CAIR) and the Regional Greenhouse Gas Initiative (RGGI). Until the impact of these programs 

on ozone can be evaluated, new stationary source RACT requirements are premature. 

Response to all comments regarding ICI boiler RACT: 

MassDEP has re-examined this issue in light of the comments it received, but maintains that the 

position presented in the RACT analysis in its proposed Ozone SIP (Section 6, RACT) is 

appropriate. MassDEP agrees with the commenters who stated that imposition of tighter RACT 

restrictions for the ICI boiler category would not be reasonable . 

With respect to EPA's comments, MassDEP agrees that the OTC analysis of potential control 

measures summarized in Appendix 5K, Identification and Evaluation of Potential Control 

Measures, includes a recommendation that OTC member states pursue, as necessary and 

appropriate, controls on ICI boilers located at major sources consistent with guidelines shown in 

Table 4.2 of Appendix K. (As noted in Appendix K, Section 4, ICI boilers located at minor 

sources generally are not subject to emission limits .) 
Consistent with the OTC review, MassDEP analyzed the potential for tighter controls on ICI 

boilers within Massachusetts. It convened a stakeholder meeting in April 2006 to advise facilities 

with ICI boilers _>I 00 mmBtu/hour that tighter RACT measures were being considered under the 

OTC regional ozone attainment planning process. Subsequent to the meeting, MassDEP asked 

facilities to submit information concerning the existing NOx and S02 control technologies for 

each boiler and the technological feasibility and estimated costs of additional controls . 

MassDEP received comments from six facilities in 2006, all of which cited technical or 

economic constraints on the adoption of tighter RACT controls on boilers at their respective 

facilities . (As noted above, some of these comments were resubmitted as official comments on 

the proposed Ozone SIP .)' 

With the adoption, in May 2007, of the Massachusetts Clean Air Interstate Rule, 310 CMR 7.32 

(MassCAIR), all large electric generating units (EGUs) and facilities with boiler >250 mmBtulhr 

became subject to the Mass CAIR NOx cap-and-trade program, which constitutes RACT for 

these facilities . 

With respect to boilers of >_100 - 250 mmBtu/hour, MassDEP reviewed the comments submitted 

by facilities following its 2006 stakeholder meeting. The comments indicated that a number of 

facilities were subject to constraints that made additional control measures infeasible from an 

engineering perspective. They also indicated that the likely costs of additional controls for many 

of the facilities made them infeasible from an economic perspective. Based on these comments, 

MassDEP determined that it is not appropriate and necessary to adopt additional controls for ICI 

boilers of 100 - 250 mmBtu/hr and that current emission limits imposed pursuant to 310 CMR 

7.19 represents RACT. In making this determination, MassDEP considered that many of the 

affected facilities are part of the remaining industrial base in the state, and that to the extent that 

EPA has not issued updated RACT requirements that would be applied to comparable sized 

sources on a national basis (especially in upwind states outside of the OTC region), tighter 

requirements on Massachusetts' sources imposes a unreasonable economic hardship on these 

facilities . 

MassDEP continues to maintain that the NOx controls required by 310 CMR 7.19, Reasonably 

Available Control Technology (R.4 CT) for Sources of Oxides of Nitrogen (NOx), constitute NOx 

RACT under the 8-hour ozone standard for the ICI boiler category 2 as well as for major sources 

of NOx with ICI boilders for which single-source RACT determinations were made pursuant to 

310 CMR 7.19(12). 

With respect to the comment of Bob Machaver, MassDEP agrees that the Massachusetts CAIR 

program, 310 CMR 7.32, which includes a cap on NOx emissions from large electric generating 

units and large boilers will have an impact on NOx emissions. Also, the reduction of electrical 

demand, whether it takes place in the context of RGGI or otherwise, may reduce NOx emissions. 

However, RACT requirements are not based on whether an area, once it has been designated 

nonattainment, needs additional reductions for the purposes of attaining the standard. Rather, 

1 Industry responses submitted in 2006 and in response to the proposed Ozone SIP are available for EPA and public 

review. 

Z The source categories covered in this regulation are: large, medium and small boilers; stationary combustion 

turbines ; stationary reciprocating internal combustion engines; glass melting furnaces ; and miscellaneous sources. 
RACT is a technology-based requirement for nonattaimnent areas. So while, MassDEP agrees 

with the commenter with respect to his support for MassDEP's conclusions regarding RACT for 

ICI boilers, its RACT analysis for this category was independent of the anticipated impact of 

either CAIR or RGGI on ozone concentrations in Massachusetts. (As discussed in the Ozone 

SIP, however, sources covered by CAIR are deemed to meet RACT.) 

EPA comment regarding Transportation Conformity (# 20) 

The date or version of the Statewide/Regional Travel Demand Models used in preparing the 

reasonable further progress plan, the attainment demonstration, and the motor vehicle emissions 

budgets (transportation conformity budgets) should be identified . 

Response: 

The Massachusetts Office of Transportation Planning (EOT) used the latest version of the 

Massachusetts Statewide Travel Demand Model, with the latest planning assumptions, for the 

Reasonable Further Progress analysis, the 2009 attainment demonstration, and the conformity 

budget. While the Statewide Travel Demand Model is often updated, there are no specific dates 

or version numbers attached to the updates. The version used for the 2008 and 2009 conformity 

budgets was the latest update as of 10/17/07.