April 14, 2009 

Lake Michigan Air Directors Consortium 

Position Paper: Proposal for Addressing Section 110(a)(2)(D) 

The purpose of this paper is to propose an approach for addressing the “significant contribution 

to nonattainment” and “interference with maintenance” provisions in Section 110(a)(2)(D) of the 

Clean Air Act. This proposal is intended to assist EPA in designing an interstate air pollution 

transport rule in response to the U.S. Court of Appeal’s remand of the Clean Air Interstate Rule 

(CAIR). A CAIR replacement rule (for EGUs and, as noted below, large non-EGU point 

sources), in combination with on-going federal programs for other sectors (i.e., mobile and area 

sources), could serve as a complete remedy to Section 110(a)(2)(D). 

The basic approach consists of the following steps: 

(1) Identify nonattainment and maintenance areas of interest. A “monitored plus 

modeled” test is proposed in which an area will be considered if both the base year 

monitored design value (2006-2008 data) and the future year modeled value (2012 or 

2018 value) is above either the air quality standard (for nonattainment) or above a 

slightly lower threshold – i.e., 96% of the standard (for maintenance). 

(2) Quantify the contribution of individual states to nonattainment and maintenance areas 

based on regional air quality modeling, which is currently being conducted as part of 

the State Collaborative process. 

(3) Implement an appropriate remedy in the form of emission reduction requirements as a 

function of a state’s contribution to a nonattainment or maintenance area. Specifically, 

states contributing at least 1% would be subject to a base level of control and states 

contributing at least 4% would be subject to a higher level of control. (Note, a relative 

metric is proposed, rather than an absolute metric, because it is easier to understand 

and provides for consistency across pollutants and standards.) 

The base level of control should reflect, at a minimum, the CAIR Phase I program as it 

currently exists. Also, EPA should consider expanding the program to include large 

non-EGU point sources of SO2 and NOx (e.g., ICI boilers). If EPA’s revised control 

program is more stringent than CAIR Phase I, then a reasonable compliance date is 

2012. 

The intent of this position is to “lock-in” those NOx and SO2 emission reductions that 

either have occurred in recent years or are “in the pipeline” to occur over the next 

couple of years in compliance with CAIR Phase I. (Within this timeframe, additional 

emission reductions cannot be reasonably achieved.) To secure these reductions in a 

CAIR replacement rule, EPA may need to tweak the budgets (e.g., re-calculate 

budgets using recent max heat input levels in combination with a “reasonable” 

emission rate, similar to what EPA did for the annual NOx CAIR budgets, but without 

making any fuel adjustments). Additionally, EPA may need to impose restrictions on 

trading and use of banked allowances. 
April 14, 2009 

The higher level of control should represent what is necessary to satisfy Section 

110(a)(2)(D) and is likely to be more stringent than the current CAIR Phase II program. 

Again, EPA should consider expanding the program to include large non-EGU point 

sources of SO2 and NOx (e.g., ICI boilers). If EPA’s revised control program is more 

stringent than CAIR Phase II, then a reasonable compliance date is 2015. 

The intent of this position is that attainment planning is more effective (and more likely 

to succeed), if it is done on a regional basis by a limited number of the most culpable 

states. The level of control necessary will depend on the magnitude of the 

nonattainment (or maintenance) problem. Appropriate outcomes could be an upwind 

4% state reducing its emissions either to get below the 4% threshold or to help provide 

for attainment in the downwind nonattainment area(s). An upwind 4% state can also 

satisfy the requirements of Section 110(a)(2)(D), if it adopts all reasonable control 

measures. 

Limited emissions trading and banking should be part of the program. Trading can be 

either intra-state, or inter-state with geographic restrictions (e.g., within a multi-state 

nonattainment area or only among states contributing at least 4%). Any banking 

should involve strong flow control. 

The intent of this position is to both provide compliance flexibility for states and 

address the Court’s concern about open trading. Under the proposed approach, all 

states contributing at least 4% to a downwind nonattainment or maintenance area can 

trade with each other. 

Finally, the Section 110(a)(2)(D) provision concerning ‘interfering with measures to protect 

visibility’ is satisfied by a state submitting (and EPA approving) a regional haze SIP which meets 

Part C, Subpart I, and by recognizing that, under the proposed hybrid approach above, the 

additional SO2 and NOx emission reductions will provide public health as well as public welfare 

(visibility) benefits.