1 

### Analysis of State ­ and County

­ Level PM 2.5 

### Benefits

Overview

The Regulatory Impact Analysis (RIA) accompanying the recently proposed Toxics Rule summarized the national and regional PM 2.5 ‐related health co‐benefits associated with the rule (EPA, 2011). Due to data, time and resource constraints, EPA di d not report these co‐benefits at a sub‐regional level. In this Tech nical Support Doc ument (TSD) we describe our approach for allocating the n ational‐level PM 2.5 ‐related monetized benefits to the state, and the county‐level avoided premature deaths to the county. We also summarize the r esults of this analysis and
describe the limitations and unc ertainties associated with our approach. A key limitation of our approach is that it does not completely account for PM 2.5 transport between states, and so may
under‐ or over‐estimate PM‐related co‐benefits for certain stat es.

Methodology

As noted in the RIA, the air quality modeling scenario used in developing national benefits estimates for the Toxics Rule reflected an early assessment of the potential utility emissions controls, and as a result, the p rojected estimates of ambient P M2.5 did not match t he expected level and spatial distribution of PM 2.5 levels resulting from the specific emissions changes that are associated with implementation o f the actual proposed rule; tim e limitations prevented EPA from modeling the air quality changes associated with emissions cont rols estimated to result from the proposed rule. For thi s reason, in estimating the national tota l PM2.5 related benefits of the proposed rule, EPA applied a bene fit per‐ton approach, in which it scaled the PM 2.5 co‐benefits estimated from the air quality modeled scenario based on the re lative national levels of SO2 emission reductions; this proce dure is described in the PM 2.5 co‐benefits chapter of the RIA. A key limitation of the benefit‐per to n approach is that it generally provides a very limited characterization of the benefits at a sub‐regional (i.e. state or county) scale. However, spatially
resolved estimates of the co‐ben efits are clearly very useful t o understanding how the expected
benefits of this rule are di stributed across the U.S.

The spatial resolution of the inp ut data to the benefits calcul ations affected the scale at which we could report the monetized benefits and premature deaths. For e xample, estimates of premature
death were calculated in BenMAP (prior to the scaling exercise) using a combination of national and county data, which gives us grea ter confidence in reporting cou nty‐level results. The total
monetized benefits were calculate d using a combination of natio nal, regional and county‐level data, giving us greater confidence in reporting state‐level results.

For this reason, EPA developed a n approximation approach for al locating the nat ional‐level PM 2.5 co‐benefits estimated in the Toxics Rule RIA to the state and c ounty level. Below we first summarize our approach for calculating state‐level monetized benefits and then detail our methods for2 estimating the number of prematu re deaths avoided at each count y. This approach is subject to important uncertainties, which we also describe below.

Allocating the national‐level PM 2.5 monetized co‐benefits to the state‐level

EPA followed the sequence of step s below to allocate the nation al‐level PM 2.5 monetized co‐benefits
to each state.

1. Estimate the state

­ level monetized co

­ benefits of the air quality modeled scenario . Using the environmental Benefits Mapping a nd Analysis Program (Abt, 2008) , EPA quantified the
total monetized PM 2.5 ‐related co‐benefits of the air quality modeled scenario for ea ch state. The methods for estimating the monetized benefits of changes in PM 2.5 air quality levels are detailed in the co‐benefits chapter of the RIA.

2. Calculate the percentage change in state

­ level SO 2 reductions between the modeled and proposed policy cases . There were significant changes in both the size and distribut ion of SO 2 emission reductions between the modeled and proposed policy cas e; this step accounts for the percentage change in SO 2 reductions for each state. 1
3. Scale the state

­ level monetized co

­ benefits according to the percentage change in SO 2 emissions between the air quality modeled and final policy cases. In this final step, the state‐
level monetized co‐benefits esti mated in step 1 is adjusted acc ording to the percentage calculated in step 2.

Allocating the natio nal‐level avoided PM 2.5 premature deaths to the county‐level

EPA followed the sequence of step s below to allocate the nation al‐level avoided PM 2.5 premature deaths to each county.

1. Estimate the number of avoided PM 2.5 ­ related premature deaths of the air quality modeled

scenario for each county . Using the environmental Benefi ts Mapping and Analysis Program (Abt, 2008), for each county EPA quantified the number of PM 2.5 ‐related premature deaths avoided resulting from the air q uality modeled scenario. The me thods for estimating the
number of avoided PM 2.5 ‐related deaths are detailed in the co‐benefits chapter of the RIA.

2. Calculate the percentage change in state

­ level SO 2 reductions between the modeled and proposed policy cases . There were significant changes in both the size and distribut ion of SO 2 emission reductions between the modeled and proposed policy cas e; this step accounts for the percentage change in SO 2 reductions for each state.

1 The Toxics Rule changed the level and distribution of PM 2.5 precursors, including SO 2 , NO x and directly

‐ emitted

PM 2.5 . However, as we describe in the RIA, we scaled the PM 2.5 ‐ related benefits of changes in SO2 emissions alone
for three reasons: (1) the great majority of the emission reductions were of SO 2 ; (2) changes in directly PM 2.5 resulted in relatively small benefits overall; (3) the complex and non

‐ linear chemistry governing nitrate PM formation made it challenging to generate a benefit per

‐ ton estimate for this precursor.3 3. Scale the county

­ level avoided PM2.5 deaths according to the percentage change in SO 2 emissions between the air quality modeled and final policy cases for each state. In this final step, the number of PM 2.5 related deaths avoided in each county in step 1 is adjusted according to the percentage chan ge in SO2 emissions for that st ate calculated in step 2.

Limitations and uncertainties

The method described above adds u nique uncertainties and limita tions beyond those already
described in detail in t he co‐benefits chapter:

1. This approach does not account fully for the transport of PM 2.5 between states . This method
assumes that the PM 2.5 ‐related monetized benefits and avoided deaths are proportional to the change in PM 2.5 precursors in that state. Howev er, emission changes in one sta te affect
the PM 2.5 levels in neighboring states. As a result, we may under‐ or ov er‐estimate the PM 2.5 monetized benefits and avoided mortalities in each state.

2. This approach does not account for the transport of PM 2.5 within states . This method assumes that the number of avoided deaths in each county within each st ate scales according to the change in emissions between the a ir quality modeled and policy case in that state. As a result, this method does not acco unt for the fact that the loca tion of emissions within the state are likely to also change, which would affect the number of avoided deaths in each
county.

3. States in which no SO 2 emissions are reduced are allocated no benefits . For Kentucky we estimate no change in PM‐related deaths or monetized benefits d ue to the fact that the final policy scenario did not apply any SO 2 emission controls to units in Kentucky; this reflects the results of a recent settlement with the Tennessee Valley Au thority that went into effect after the completion of the air quality modeling but before the rule was proposed. However, because upwind states have significantly reduced SO 2 emissions, we expect Kentucky to receive significant PM 2.5 ‐related co‐benefits under the proposed rule.

Results

Below we report the PM 2.5 ‐related monetized co‐benefits i n each state (Table 1). We also provide a map of the monetized co‐benefits in each state (Figure 1) and t he number of PM 2.5 ‐related deaths avoided in each county (Figure 2).4 Table 1: Estimated PM 2.5 ­ related Monetized Co

­ Benefits for Each State

State Total Monetized Benefits (3% discount rate, millions of 2007$) Pope et al. (2002) mortality estimate Laden et al. (2006) mortality estimate

Alabama $1,600 $3,900

Arizona $400 $1,000

Arkansas $1,200 $2,800

California $580 $1,400

Colorado $410 $990

Connecticut $2,400 $5,900

Delaware $250 $620

DC $130 $320

Florida $4,700 $12,000
Georgia $880 $2,100

Idaho $18 $45

Illinois $1,900 $4,600

Indiana $1,100 $2,600

Iowa $550 $1,300

Kansas $680 $1,700
Kentucky --- A --- A

Louisiana $1,300 $3,300

Maine $75 $180
Maryland $1,300 $3,200

Massachusetts $2,700 $6,700
Michigan $2,400 $5,800

Minnesota $580 $1,400
Mississippi $480 $1,200

Missouri $1,400 $3,500

Montana $75 $190

Nebraska $320 $790

Nevada $17 $43
New Hampshire $200 $490
New Jersey $6,700 $16,000

New Mexico $100 $2505 New York $5,100 $12,000

North Carolina $1,700 $4,100

North Dakota $79 $190

Ohio $2,700 $6,700

Oklahoma $1,100 $2,600
Oregon $11 $28
Pennsylvania $3,300 $8,200

Rhode Island --- A --- A

South Carolina $1,800 $4,400

South Dakota $130 $320

Tennessee $2,500 $6,200

Texas $8,800 $22,000

Utah $94 $230

Vermont --- A --- A
Virginia $2,000 $4,900
Washington --- A --- A
West Virginia $650 $1,600

Wisconsin $1,300 $3,100
Wyoming $16 $38

A

While methodological limitations prevented us from estimating PM 2.5 -related benefits in these states, emission reductions from neighboring states are likely to provide PM 2.5 -related benefits.