Final Section 2 - Page 1 of 4

SECTION 2 EMISSIONS INVENTORIES

2.1 Purpose of Section 

The CAA and EPA regulations require that states compile estimates of certain air pollutants 

emitted from sources within their borders. States with moderate or above ozone nonattainment 

areas must prepare emission inventories of VOCs, NOx and CO every three years and must 

include the latest inventory of these pollutants in their attainment demonstration SIP. The 

Massachusetts 2002 Base Year Emissions Inventory – September 2007 (MA 2002 Base Year 

Inventory, Appendix 2A to this document) satisfies the inventory requirements for the EMA and 

WMA ozone nonattainment areas. This Section provides a brief summary of the Mass 2002 Base 

Year Inventory results.

For the purposes of showing the overall downward trend of emissions in Massachusetts, this 

Section also provides a summary of the 2008 projections developed to demonstrate RFP (See 

Section 4, Reasonable Further Progress), the 2009 projections used in the ozone attainment 

modeling (See Section 5, Attainment Demonstration) and summary of projected emissions in 

2012. 

2.2 2002 Base Year Inventory Pollutants 

The MA 2002 Base Year Inventory estimates in-state emissions of the following pollutants as of 

2002: VOCs, NOx, CO, particulate matter (PM1), ammonia (NH3) and sulfur dioxide (SO2). In 

addition to meeting the inventory requirements for ozone nonattainment areas, the inventory

meets the requirements of EPA’s 2002 Consolidated Emissions Reporting Rule (CERR). The 

CERR requires that, irrespective of a state’s NAAQS attainment status, every three years it must 

develop and update a single, statewide annual inventory of the following pollutants: VOCs, NOx, 

CO, PM, NH3 and SO2. The MA 2002 Base Year Inventory estimates annual emissions of 

pollutants from all source sectors in the state, as required by the CERR. 

Because high ozone concentrations are generally associated with warmer weather and emissions 

may vary seasonally, the inventory also includes emissions estimates of VOCs, NOx, and CO on 

a ton per summer day (TPSD) basis.

A June 2006 version of the MA 2002 Base Year Inventory was available for informal public 

review on MassDEP’s website from July 2006 through October 2007. The September 2007 

version (Appendix 2A) makes minor revisions to the Introduction of the June 2006 version, 

(Section 1), and includes methodology changes for Section 3.3-2, Surface Cleaning/Degreasing

and Section 3.3-7, Cutback and Emulsified Asphalt Paving. It also adds a section estimating 

emissions from Adhesives and Sealants. The complete MA 2002 Base Year Inventory - September 

2007 is part of this Massachusetts 8-Hour Ozone Attainment Demonstration SIP; it is available on 

MassDEP’s web site at: http://mass.gov/dep/air/priorities/aqdata.htm. It contains extensive 

 

1 The inventory includes estimates of both PM10 and PM2.5. PM10 refers to particles equal to or smaller 

than 10 micrometers in diameter. PM2.5 refers to particles equal to or smaller than 2.5 micrometers in 

diameter. 
Final Section 2 - Page 2 of 4

narrative explaining the methodology for development of the inventory and the extensive data 

files supporting the emission estimates. 

2.3 2008 and 2009 Projected Inventories

In addition to calculating emissions in the base year, nonattainment areas must also estimate 

emissions in future milestone years. For purposes of demonstrating RFP towards attainment, 

areas must project emissions for the RFP milestone year – 2008 for EMA and WMA. EPA’s 

Phase 2 Rule established 2002 as the base year for demonstrating compliance with the 8-hour 

ozone standard RFP requirements. For purposes of RFP, areas may take credit for reductions that 

occur subsequent to 2002, but before their RFP milestone year. (The methodology for developing 

the 2008 projections is discussed in Section 4, Reasonable Further Progress.) 

To demonstrate attainment, areas must project emissions in the attainment year for use in their 

modeled attainment demonstration. For attainment demonstration purposes, EPA recommended, 

but did not require, that states use 2002 as the baseline year for their attainment demonstration 

modeling. MassDEP is using 2002 as its base year for the 2009 regional attainment modeling, as 

discussed in Section 5, Attainment Demonstration. (The methodology for developing the 2009 

projections is also discussed in Section 5.)

2.4 2012 Projected Inventory

Massachusetts is not required to estimate emissions in years subsequent to its 2009 attainment year 

for 8-hour ozone purposes. However, to comply with the requirements of an EPA rule related to 

Regional Haze,2,the Mid-Atlantic/Northeast Visibility Union (MANE-VU)3developed emissions 

estimates for 2012 for all states in the MANE-VU region, including Massachusetts. Because these 

2012 estimates4are available, MassDEP has included them in Table 2.1 below in order to 

demonstrate the continued downward trend in Massachusetts’ emissions. 

2.5 Emissions Inventory Trends

Table EI -1 provides the statewide ozone season 2002 MA Base Year Inventory emissions of VOC 

and NOx by source sector and the projected emissions for each sector in 2008, 2009 and 2012. 

Figures 2-1 and 2-2 illustrate the reductions of VOCs and NOx that are projected to take place in 

Massachusetts by the 2008 milestone year for RFP, by the 2009 attainment demonstration milestone 

year, and by 2012. Note that because of different methods use to project emissions from the various 

 

2 EPA’s Regional Haze Rule requires that states address regional haze and visibility impairment in Class 

1 Federal areas (certain parks and wilderness areas). This is a separate EPA rule unrelated to ozone 

attainment. 

3 The Mid-Atlantic and Northeastern states, tribes, and federal agencies formed MANE-VU to coordinate 

regional haze planning activities for the region.

4 Mid-Atlantic Regional Air Management Association, Development of Emission Projections for 2009, 

2012 and 2018 for NonEGU Point, Area, and Nonroad Sources in the MANE-VU Region, Final Report, 

February 2007. www.marama.org/visibility/Inventory%20Summary/FutureEmissionsInventory.htm
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sectors in the three projection years, estimates are only roughly comparable. As noted above, the 

methods used to develop the 2008 and 2009 are discussed in Sections 4 and 5. 

Table EI - 1 MA 2002 Emissions and Projections for 2008, 2009** and 2012**

STATEWIDE

2002 Base 

Year VOC VOC 2008 VOC 2009 VOC 2012

2002 Base 

Year NOx NOx 2008 NOx 2009 NOx 2012

Tons per summer 

day Projected Projected Projected Projected Projected Projected

Point EGU

Point Non-EGU

POINT TOTAL 

1.5

14.5

16.0

1.4 

15.0 

16.4

1.4 

15.2 

16.6

1.5 16.5 

18.0

82.8

46.8

 129.6

37.3 

48.4 85.8

56.0 

 47.7 

103.7

56.0 

 49.5 

105.5

AREA 327.6 332.4 277.9 268.3 39.1 44.0 44.5 45.3

ON-ROAD*** 151.9 80.1 74.2 56.2 453.1 222.6 202.7 132.4

OFF-ROAD 223.8 178.9 171.6 159.8 144.6 128.4 124.3 105.8

TOTAL 719.3 607.7 540.3 502.3 766.3 480.7 475.2 389.0

** As discussed in Section 5, Attainment Demonstration, 2009 projections used in attainment modeling are based on:

1) Appendix 5L – Development of Emission Projections for NonEGU Point, Area and Nonroad Sources in the MANE-VU Region,

prepared by MACTEC Federal Programs, Inc., February 2007; 2) Mobile Source emissions developed by

NESCAUM, with Mobile 6.2 inputs provided by the states; and 3) Integrated Planning Model (IPM) runs for

EGU emissions (see List of References – Reference #8 re: IPM runs). 2012 EGU projections are also based on IPM runs. 

IPM projections are for the May - September ozone season. MassDEP has derived a tons per summer day estimate from

the IPM ozone season estimate (ozone season emissions/153 days.) 

*** On-Road Mobile projections are based on the estimates developed for the 2008 and 2009 Conformity Budgets

(described in Section 9, Transportation Conformity). For 2012, MassDEP extrapolated from the 2009 projections. 

File: rfp-2002-12-trends nov/21/2007

By 2008, MassDEP estimates that statewide emissions of VOCs during the summer ozone season

(May –September) will decrease from 2002 levels by 16% and of NOx by 37%. As discussed in 

Section 4, Reasonable Further Progress, EMA and WMA are able to demonstrate that reductions of 

VOC and NOx by 2008 in each area will substantially exceed the required 15% reduction needed to 

demonstrate RFP toward attainment. 

By 2009, MassDEP estimates that statewide emissions of VOCs during the summer ozone season 

will decrease from 2002 levels by 25% and of NOx by 38%. These reductions are the result of both 

existing and new Massachusetts and federal control measures. As discussed in Section 3, Control 

Measures, and Section 5, Attainment Demonstration, the 2009 projected emissions inventory5used 

in the OTC modeling process incorporates these anticipated reductions in Massachusetts. 

By 2012, MassDEP estimates that statewide emissions of VOCs will decrease from 2002 levels by

30% and of NOx by 49%. These reductions will result from state and federal control measures 

already in effect and taken into account in the 2009 attainment demonstration. Additional reductions 

 

5 It should be noted that the inventory data used in the attainment modeling is based on annual emissions (as 

discussed in Section 5), rather than summer ozone season emissions. Therefore, percentage reductions that are cited 

in Section 5 may differ from the estimates provided in this Section. 
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will continue to accrue from these measures and ensure that ozone concentrations will continue to 

decrease in years subsequent to the 2009 attainment demonstration year. 

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Projected % VOC Reductions from 2002

Figure 2.1 Projected Anthropogenic VOC Emission Trends for 

MA

Off-Road

On-Road

Area

Point

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-38%

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-49%

Projected % NOx Reductions from 2002

Figure 2.2 Projected Anthropogenic NOx Emission 

Trends for MA

Off-Road

On-Road

Area

Point