DEVAL L. PATRICK 

Governor 

TIMOTHY P. MURRAY 

Lieutenant Governor 

COMMONWEALTH OF MASSACHUSETTS 

EXECUTIVE OFFICE OF ENERGY & ENVIRONMENTAL AFFAIRS 

DEPARTMENT OF ENVIRONMENTAL PROTECTION 

ONE WINTER STREET, BOSTON, MA 02108 617-292-5500 

IAN A. BOWLES 

Secretary 

LAURIE BURT 

Commissioner 

Revision to the 

Carbon Monoxide Maintenance 

State Implementation Plan for 

Lowell, Massachusetts 

Bureau of Waste Prevention 

December 2009 

This information is available in alternate format. Call Donald M. Gomes, ADA Coordinator at 617-556-10.57. TDD# 1-866-539-7622 or 1-617-574-6868. 

MassDEP on the World Wide Web: http ://www .mass.gov/dep 

11004 Printed on Recycled Paper 
December 2009 Revision to Lowell CO Maintenance Plan 

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REVISION TO THE 

CARBON MONOXIDE MAINTENANCE STATE IMPLEMENTATION PLAN 

FOR LOWELL, MASSACHUSETTS 

Summary 

This is a revision to the 2001 Massachusetts Carbon Monoxide (CO) Maintenance State 

Implementation Plan (SIP) for the City of Lowell (the 2001 Maintenance Plan). The 

Massachusetts Department of Environmental Protection (MassDEP) is revising the 2001 

Maintenance Plan by eliminating the requirement to monitor CO concentrations in the ambient 

air in Lowell. Instead, MassDEP will verify continued attainment of the National Ambient Air 

Quality Standard (NAAQS) for CO in Lowell by using the CO monitor located in the City of 

Worcester as a surrogate. MassDEP will also use the Worcester monitor data as the trigger for 

adoption in Lowell of contingency measures in the event that the CO NAAQS is violated. 

MassDEP will discontinue CO monitoring in Lowell because monitored CO readings in Lowell 

have been well below the CO NAAQS for many years. The staff and resources used to monitor 

CO in Lowell will be reallocated to other monitoring efforts upon the U.S. Environmental 

Protection Agency's (EPA's) approval of this SIP revision . 

Background 

Carbon monoxide is a colorless, odorless gas emitted as a by-product of incomplete combustion 

of fossil fuels . When inhaled, CO has a high affinity for the body's red blood cells, and displaces 

the oxygen molecules carried to organs and other tissues . The NAAQS for CO promulgated by 

the U.S . Environmental Protection Agency (EPA) to protect public health and welfare is 9.0 

parts per million (ppm) averaged over an eight-hour period, and 35 .0 parts per million averaged 

over one-hour. The CO NAAQS may not be exceeded more than once per year at any monitoring 

site. 

To measure the concentration of CO in the ambient air, MassDEP has operated one CO monitor 

in Lowell, one in Springfield, one in Worcester and two in Boston. The monitors have been 

continuously operated for more than 15 years. MassDEP has routinely collected and quality 

assured the CO data from these stations in accordance with 40 CFR 58. 

Lowell was first designated as a non-attainment area for CO in 1978 (43 FR 9003). CO 

emissions were significantly reduced as a result of state and federal control measures throughout 

the 1980s and 1990s, particularly from controls on motor vehicles .' On November 6, 1991, as 

1 Federal mobile source reduction strategies include the pre-1990 Federal Motor Vehicle Control Program 

(FMVCP), federal Tier I emission standards for newly manufactured cars and trucks (phased-in beginning 

with the 1994 model year), and reformulated gasoline (beginning in January 1995). In 1983, 

Massachusetts began implementation of a basic inspection and maintenance program for on-road 
December 2009 Revision to Lowell CO Maintenance Plan 

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required by the 1990 Clean Air Act Amendments, EPA designated Lowell as an unclassifiable z 

non-attainment area for C0.3 At that time, monitored readings of CO in Lowell were already 

below the CO NAAQS, but the 1990 Clean Air Act Amendments required that the area remain 

classified as a non-attainment area, even though-ambient monitoring showed attainment at that 

time . 

On May 25, 2001, MassDEP submitted to EPA a request that Lowell (and Springfield, Waltham 

and Worcester) be redesignated to attainment . 4 It also submitted a Maintenance Plan for Lowell 

demonstrating how the area would maintain compliance with the NAAQS for the next 10 years . 

The submittal was based on EPA's Limited Maintenance Plan option guidance. The Limited 

Maintenance Plan option was available to non-classifiable CO non-attainment areas seeking 

redesignation, provided that monitored design values were at or below 7.65 ppm (85% of the 8-

hour NAAQS) . The monitored data for Lowell qualified the area for this option . On February 

19, 2002, EPA approved the redesignation request and 2001 Maintenance Plan for Lowell (and 

for Springfield, Waltham and Worcester). (See 67 FR 7272).5 

Current CO Status 

As illustrated in Figure 1, monitored CO levels throughout Massachusetts have fallen 

significantly since the 1980s. There has not been a violation of the NAAQS in Lowell since 

1984. For the 2005-2008 period, the second-highest monitored 8-hour concentrations in Lowell 

and Worcester have been under 2.2 ppm - less than one-quarter of the standard . 6 

vehicles . It implemented an enhanced inspection and maintenance program starting in 1999 . Local traffic 

flow improvements were implemented in heavily congested areas to reduce CO concentrations . 

z Non-classifiable means that there were no air quality measurements that would justify classifying these 

non-attainment areas as either serious or moderate non-attainment areas . 

3 At the time that EPA designated Lowell, it also designated Springfield, Waltham and Worcester as CO 

nonattainment areas. Like Lowell, these cities have been re-designated to attainment, are subject to a 

Maintenance Plan, and have monitored readings well below the CO NAAQS . The Maintenance Plan 

revision for Lowell will have no impact on the Maintenance Plans that apply to these cities . 

4 The Redesignation Request, including the Technical Support document and Maintenance Plan 

~rovisions, is available on MassDEP's website at : www.mass.gov/dep/air/priorities/cotsd .doc 

These were the last MA cities to be redesignated for CO. Nine Boston-area communities were 

redesignated to attainment in 1999. 

6 Since a monitor must exceed the NAAQS of 9.0 ppm more than once a year to violate the standard, the 

second highest eight-hour value recorded each year is the indicator of attainment. 
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FIGURE 1: CO Trends 1985-2008 

2"a Maximum 8-hour Values 

Standard = 9 ppm 

85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 

--s -"' LOWELL --E- SPRGFLD(E Columbus) SPRGFLD(Liberty St) 

WORC(Central St) 020 )K - WORC(Franklin St) 022 -e - WORC(Sunmer St) 023 

(Note: only the Summer Street monitor in Worcester remains in operation.) 

Worcester Monitor 

Given the low CO concentrations in Lowell and throughout Massachusetts, and MassDEP's 

expectation that CO levels will remain well below the NAAQS, MassDEP will shut down the 

CO monitor in Lowell upon EPA's approval of this SIP Revision. Only CO is monitored at the 

existing Lowell monitor and MassDEP allocates considerable staff and other resources to 

maintain the monitoring and support equipment, to travel to and from the site to collect data, and 

to conduct routine and emergency maintenance at the site . 

The approved 2001 Maintenance Plan, Section 7 .4, Monitoring Network and Verification of 

Future Attainment, provides that MassDEP will continue to operate an appropriate air quality 

monitoring network during the maintenance period to verify the attainment status of the area and 

that it will operate CO monitors in Lowell, Springfield, and Worcester. MassDEP will use the 

Worcester monitor as a surrogate for Lowell to meet this commitment. Worcester and Lowell 

are located 42 miles apart. Worcester (pop. 175,454) is somewhat larger than Lowell (pop. 

103,229), so its CO concentrations can be expected to be slightly higher due to greater motor 

vehicle emissions. Both monitors are located adjacent to high traffic volume intersections, 

which are generally areas of the highest CO concentrations . As shown in Figure 2, CO 

concentrations in Lowell and Worcester have tracked very closely for many years and both are 

well below the NAAQS. Based on these characteristics, ambient CO concentrations in 

Worcester are a valid surrogate for CO concentrations in Lowell. 

Once MassDEP begins to use the Worcester monitor as a surrogate, in the event the secondhighest monitored CO concentration in any calendar year in Worcester reaches 75 percent of the 
December 2009 Revision to Lowell CO Maintenance Plan 

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federal 1-hour or 8-hour NAAQS for CO, MassDEP will, within 9 months of the date such 

concentrations are recorded, re-establish a CO monitoring site in Lowell consistent with EPA 

siting criteria, and resume analyzing and reporting CO concentrations in Lowell. 

FIGURE 2 : Lowell, MA Compared to Worcester, MA 

2"a Highest 8-Hour Average Carbon Monoxide Concentration 

(NAAQS = 9.0 ppm) 

I 

E3 Low ell w Worcester 

Contingency Plan Trigger 

The Clean Air Act requires that maintenance plans include contingency provisions that will be 

implemented in the event that a violation of the NAAQS occurs after redesignation of the area to 

attainment . In Section 7.5, Contingency Plan, of the approved 2002 CO Maintenance Plan, 

MassDEP committed to implement the contingency plan if monitored CO concentrations in 

Lowell (or in Springfield, Waltham, or Worcester) violated the NAAQS, provided that the data 

met quality assurance criteria and did not qualify for exclusion under EPA's "exceptional 

events" policy . 

In the approved 2001Maintenance Plan, the trigger for implementing the contingency plan in 

Lowell was a violation at the Lowell monitor. Once the Lowell monitor is shut down, MassDEP 

will use the Worcester monitor data as the trigger for implementation of the contingency plan for 

Lowell . If the Worcester monitor measures a CO violation of either the 1-hour or 8-hour 

NAAQS for CO, MassDEP will implement contingency measures (discussed below) in Lowell. 

(A violation at the Worcester monitor will also trigger contingency measures in Worcester under 
December 2009 Revision to Lowell CO Maintenance Plan 

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the terms of the existing Maintenance Plan for Worcester.) In the event that MassDEP reestablishes a CO monitor in Lowell (because the second-highest CO concentration in any 

calendar year in Worcester reaches 75 percent of the NAAQS, as discussed above), a violation of 

the NAAQS at the re-established Lowell monitor will trigger the contingency plan for Lowell . 

(In this case, a violation at the Worcester monitor would no longer trigger contingency measures 

in Lowell.) 

Contingency Measures 

The contingency plan measures that MassDEP committed to in 2001 are: 1) to investigate traffic 

conditions in the local vicinity of the monitor measuring violation, and work with relevant 

parties and officials to remedy the problem through local measures, such as traffic signal changes 

and revised parking restrictions ; 2) to further reduce CO emissions based on implementation of 

the Massachusetts enhanced vehicle inspection/maintenance (I/M) program; and 3) to further 

reduce CO emissions based on implementation of the California low-emission vehicle (LEV) 

program. Subsequent to the approval of the 2001 Maintenance Plan in 2002, MassDEP adopted 

the second and third measures - enhanced I/M and LEV - for purposes of reducing ground-level 

ozone concentrations . 

In the unlikely event that the contingency plan is triggered for Lowell by a monitored violation at 

the Worcester monitor, or at a re-established Lowell monitor, MassDEP will implement 

measures necessary to remedy the violation. It will first implement the first contingency measure 

described in the 2001 CO Maintenance Plan related to local traffic conditions . It will also review 

and adopt transportation control measures, or other additional vehicle or fuel controls as needed, 

to reduce monitored concentrations to levels that meet the NAAQS.