Anchorage
CO Limited Maintenance
Plan
A plan addressing the second 10
years of the 2004 -2024 CO
maintenance planning period
Department of Health and Human Services
Municipality of Anchorage
October 2012
Anchorage CO Plan
Update
Section 175A of the Clean Air Act requires
the submission of a maintenance plan
revision midway through the twenty year
maintenance planning period.



Anchorage’s twenty year CO Maintenance planning period
runs from July 23, 2004 through July 22, 2024.
The Anchorage revision must address second ten years
(July 2014 – July 2024)
The draft Anchorage CO Maintenance Plan revision was
prepared using the limited maintenance plan (LMP) option.
Anchorage CO Plan
Update
What the heck is a “limited
maintenance plan”?
Anchorage CO Plan
Update

EPA offers LMP option to areas where the design
value is 85% or less of the CO standard.
– CO NAAQS = 9 ppm (as 8-hr average)
– 85% of CO NAAQS = 7.65 ppm
– Anchorage DV (2011) = 6.0 ppm


Preparation of the CO maintenance plan revision
under the LMP option is simpler and less rigorous
than a full maintenance plan revision.
Once EPA approves an LMP, regional air quality
conformity procedures are greatly simplified.
Anchorage CO Plan
Update
The Anchorage CO LMP was prepared in
accordance with EPA guidance contained in the
“Paise memo” drafted in 1995.
This guidance discusses how the five core
provisions of an LMP should be addressed:
1. attainment inventory
2. maintenance demonstration
3. monitoring to verify continued attainment of the CO
NAAQS
4. a contingency plan
5. conformity determination requirements under an LMP.
Anchorage CO Plan
Update
Attainment inventory
Sources of CO Emissions in Anchorage Bowl (2007)
CO Emitted
(tons per day)
% of total
Motor vehicle – running emissions
40.5
25.4%
Motor vehicle – start emissions
84.8
53.4%
Motor vehicle – extended idling by combination long-haul trucks
0.3
0.1%
Subtotal – Motor Vehicles
125.6
78.9%
Ted Stevens Anchorage International Airport Operations
12.4
7.8%
Merrill Field Airport Operations
0.7
0.4%
Wood burning – fireplaces and wood stoves
6.2
3.9%
Space heating – natural gas
3.8
2.4%
Miscellaneous (railroad, marine, snowmobiles, snow removal, portable
electrical generators, welding, etc.)
9.3
5.8%
Point sources (power generation, sewage sludge incineration)
1.3
0.8%
Subtotal – Other Sources
33.7
21.1%
TOTAL – ALL SOURCES
159.3
100%
Source Category
Anchorage CO Plan
Update
Maintenance Demonstration
The update must show that the DV in Anchorage qualifies
for the LMP option
Highest 2nd Max 8-hr Concentration Measured
in Preceding Two-Years (all values in ppm)
Garden
Seward
Hwy
Turnagain
2002
5.7
5.2
7.7
7.7
2003
5.7
5.4
6.7
6.7
2004
6.4
5.5
7.9
7.9
2005
6.4
7.9
7.9
2006
4.8
6.1
6.1
2007
4.3
6.1
6.1
2008
3.8
5.5
3.1
5.5
2009
4.4
5.8
3.6
5.8
2010
4.4
6.0
3.6
6.0
2011
3.8
6.0
2.8
6.0
Anchorage CO Plan
Update
DHHS
DVPaise
DV has been
≤ 7.65 ppm
since 2006.
The update continues the commitment to implement the
primary control measures currently included in the
maintenance plan:

Air quality public awareness
program

Transit marketing

Carpooling and Vanpooling
Anchorage CO Plan
Update
Monitoring to verify continued
attainment of the CO NAAQS
The update commits Anchorage and/or State of Alaska to
continued monitoring to verify compliance with the CO
standard
The current CO network includes four
sites. The highest concentrations are
measured at the Turnagain site in
residential Spenard.
Anchorage CO Plan
Update
Contingency plan
The previous plan included a commitment to implement at least one
of six contingency measures if a future violation of the CO standard
occurs. The update affirms this commitment.
Menu of Contingency Measures
1) Increasing public awareness, transit marketing and carpool/vanpool
efforts
2) Curtailing or limiting the use of fireplaces and woodstoves when high
CO is predicted
3) Offering reduced fares or free transit for employees of companies that
contribute to transit subsidies
4) Reinstating the engine block heater installation subsidy
5) Reinstating the ethanol blended gasoline requirement
6) Reinstating the I/M Program
Anchorage CO Plan
Update
Conformity determinations
under an LMP
A motor vehicle emission budget is not required in an LMP.
EPA guidance states that “emissions budgets in limited
maintenance plan areas may be treated as essentially not
constraining.”
The EPA has concluded that for transportation purposes, the
emissions in a qualifying LMP area need not be capped for the
maintenance period and thus no emissions budget is required in
the maintenance plan.
Anchorage CO Plan
Update
Tentative Approval Schedule
AMATS TAC release of draft CO LMP for 30-day public review
Sept 13, 2012
AMATS AQ Committee review and recommendation
Oct 2, 2012
AMATS TAC recommendation on CO LMP
Oct 11, 2012
AMATS Policy Committee review/approval of CO LMP
Oct 25, 2012
Anchorage Assembly considers CO LMP for adoption
Nov 13, 2012
ADEC public review process
Dec 2012 – Jan 2013
ADEC legal review, adoption of CO LMP as a revision to the SIP
Feb 2013 – May 2013
ADEC submits SIP revision to EPA for approval
Jun 2013
EPA adequacy review of new conformity procedure (up to 90 days)
Jun 2013 – Aug 2013
Anchorage CO Plan
Update