Technical Support Document: Calculating Benefit Per-Ton estimates

Overview

The estimates of the full attainment PM2.5 co-benefits in the final
Ozone Regulatory Impact Analysis are a composite of the benefits of the
modeled attainment scenario and benefits calculated using benefit
per-ton metrics. This technical support document (TSD) describes the
steps we took to calculate the benefit per-ton metrics that were used as
the basis for estimating the PM2.5 co-benefits. This document focuses
specifically on the steps followed to calculate the benefit per ton
metrics and makes extensive reference to previous documents that
describe the air quality modeling data that provided the inputs to these
benefit estimates. 

Summary of Calculation Steps

The basic calculation steps were as follows:

Model the national changes in ambient PM2.5associated with 25%, 50% and
75% reductions in PM2.5 precursors from various classes of industrial
sources 

Input the changes in air quality to the Environmental Benefits Mapping
and Analysis Program (BenMAP) and estimate monetized benefit estimates
of these air quality improvements

Divide the total monetized benefit by the total emission reduction

Below we provide an expanded discussion of each of these three steps.

Generating Modeled PM2.5 Concentrations

EPA employed a Response Surface Model (RSM) to generate estimated PM2.5
concentrations. The RSM uses advanced statistical techniquesto
characterize the relationship between a very complex air quality model
such as CMAQ and input parameters in a highly economical manner.The RSM
is simply a reduced-form prediction model that uses statistical
correlation structures to approximate model functionsthrough the design
ofcomplex multi-dimensionalexperiments. Additional technical detail
regarding the model may be found in the technical support document for
the PM2.5 RIA.

In this version of the PM2.5 RSM, EPA selected 12 emission control
factors based on precursor emission type and source category.  The
selection of factors was based on three fundamental areas:

type of precursor emission (NOx, SOx, NH3, POC, PEC, or VOC), 

emission source category (EGU point sources, NonEGU point sources, area
sources, agricultural sources, nonroad sources, and mobile sources)

location of urban areas contributing to residual PM2.5 after
implementation of the Clean Air Interstate Rule in 2015 and
geographically distinct in contribution to sources of PM2.5
concentrations.

This version of the PM2.5 RSM uses the 2015 CAIR inventory and included
the following 12 source pollutant factors:

NOx EGU = NOx IPM EGU point source emissions

NOx NonEGU Point and Area = NOx IPM Non-EGU point source, area source,
and agricultural source emissions 

NOx Mobile = NOx nonroad source and mobile source emissions

SOx EGU = SOx IPM EGU point source emissions

SOx NonEGU Point = SOx IPM Non-EGU point source emissions

SOx Area = SOx area source and agricultural source emissions 

NH3Area = Ammonia area source and agricultural source emissions  

NH3 Mobile = Ammonianon-road source and mobile source sources

POC/PEC Point (EGU and NonEGU) = Elemental carbon and organic carbon IPM
EGU point source and IPM Non-EGU point source emissions

POC/PEC Mobile = Elemental carbon and organic carbon nonroad source and
mobile source emissions

POC/PEC Area= Elemental carbon and organic carbon area source and
agricultural source emissions

VOC All = Volatile organic carbon IPM EGU point source, IPM Non-EGU
point source, area source, agricultural source, nonroad source, and
mobile source emissions

One of the chief analytical benefits of the RSM is that it can model the
change in air quality resulting from a change in emissions from any
given source/pollutant factor while holding all other factors constant.
For, example, the RSM can estimate the improvement in PM2.5 air quality
resulting from a 50% reduction in area source NH3 while holding other
emissions constant. This ability to hold other emissions constant is
essential to the process of creating benefit per ton estimates that are
specific to each source/pollutant combination. 

To generate estimates of changes in air quality associated with emission
reductions in each source/pollutant combination, we simulated a 25%, 50%
and 75% reduction in each of the 12 factors, each time holding all other
factors constant; this step generated 36 different air quality modeling
runs. For each modeling run, the RSM produces 36 km CMAQ air quality
grids suitable for input to the BenMAP model for subsequent generation
of benefits estimates.

Estimating Monetary Value of Human Health Benefits

We used the BenMAP model to estimate changes in human health resulting
from each of these modeling scenarios. The benefits assessment used
techniques, health impact functions and valuation functions that were
consistent with the Regulatory Impact Analysis that supported the PM2.5
National Ambient Air Quality Standards. Readers interested in a
comprehensive discussion of these methods and functions may refer to
chapter 5 of this document. 

The BenMAP model produced estimates of the change in the incidence of
health effects and estimated a monetary value for the modeled air
quality change in each of the 12 source/pollutant combinations.
Consistent with the PM2.5 NAAQS RIA, we estimated total benefits for
each modeling scenario using two different PM2.5 mortality functions:
Pope et al (2002),Laden et. al (2006) and each of the 12 Expert
Functions, at 3% and 7% discount rates. We developed these estimates for
two future years: 2015 and 2030. We chose 2015 because it was the year
in which the RSM-derived air quality changes were estimated to occur. We
chose 2030 to produce benefit per-ton estimates that could be used to
estimate the PM2.5 co-benefits of attaining the selected and alternate
ozone standards in San Joaquin and South Coast in 2030. Considering
alternate years affects the estimated population exposed, which in turn
effects the total benefit estimate.

Calculating the benefit per ton estimates

Having modeled the PM2.5 air quality change and estimated the total
valuation for each scenario, the final step was to estimate the benefit
per ton of PM2.5 precursor abated. This calculation step involved simply
dividing each valuation estimate by its corresponding reduction in PM2.5
precursor tons abated. For example, in a given scenario we reduced
emissions by 1,000 tons and benefits were $2,000,000 then the benefit
per ton would be $2,000. 

Results

Table 1 through table 4 below summarize the benefit per ton estimates
for each of the 36 scenarios.

Table 1: Estimated PM2.5 Benefit per Ton for the Year 2015 (3% Discount
Rate)

Source/Pollutant Combination	% Reduction	Pope et al.	Laden et al.	Expert
A	Expert B	Expert C

Carbon Area	25%	$251,001	$536,416	$760,305	$586,982	$580,238

	50%	$245,113	$522,275	$762,716	$589,242	$582,534

	75%	$239,852	$509,527	$764,581	$591,097	$584,434

Carbon Mobile	25%	$181,715	$388,988	$579,360	$445,831	$441,650

	50%	$179,580	$383,999	$582,718	$448,510	$444,315

	75%	$176,887	$377,770	$585,660	$450,872	$446,664

Carbon EGU & Non-EGU	25%	$153,593	$330,219	$456,061	$352,038	$347,625

	50%	$153,686	$330,019	$461,833	$356,597	$352,134

	75%	$152,924	$327,952	$467,272	$360,895	$356,384

NH3 Area	25%	$12,809	$27,435	$39,221	$30,250	$29,910

	50%	$12,901	$27,578	$40,642	$31,366	$31,004

	75%	$12,960	$27,651	$42,016	$32,450	$32,066

NH3 Mobile	25%	$29,108	$62,378	$74,722	$58,088	$57,078

	50%	$32,049	$68,633	$83,195	$64,664	$63,561

	75%	$34,987	$74,875	$91,559	$71,160	$69,965

Nox EGU	25%	$2,681	$5,733	$8,596	$6,617	$6,553

	50%	$3,240	$6,931	$10,196	$7,857	$7,774

	75%	$3,802	$8,135	$11,788	$9,090	$8,990

Nox Mobile	25%	$4,357	$9,350	$12,427	$9,630	$9,480

	50%	$4,754	$10,190	$13,588	$10,534	$10,369

	75%	$5,133	$10,989	$14,730	$11,424	$11,245

Nox NEGU	25%	$2,599	$5,578	$7,535	$5,821	$5,746

	50%	$2,956	$6,342	$8,568	$6,621	$6,534

	75%	$3,311	$7,100	$9,592	$7,415	$7,317

Sox Area	25%	$13,200	$28,264	$45,177	$34,611	$34,410

	50%	$13,735	$29,407	$46,942	$35,974	$35,758

	75%	$14,171	$30,327	$48,673	$37,313	$37,081

Sox EGU	25%	$25,214	$53,985	$82,355	$63,437	$62,785

	50%	$23,314	$49,676	$83,646	$64,474	$63,805

	75%	$21,104	$44,718	$84,856	$65,450	$64,763

Sox NEGU	25%	$15,863	$33,944	$53,892	$41,361	$41,061

	50%	$15,672	$33,477	$55,134	$42,331	$42,016

	75%	$15,503	$33,056	$56,337	$43,276	$42,943

VOC	25%	$339	$725	$1,092	$841	$833

	50%	$426	$912	$1,341	$1,034	$1,022

	75%	$512	$1,096	$1,588	$1,225	$1,211



Table 1 Continued: Estimated PM2.5 Benefit per Ton for the Year 2015 (3%
Discount Rate)

Source/Pollutant Combination	% Reduction	Expert D	Expert E	Expert F
Expert G	Expert H	Expert I	Expert J	Expert K	Expert L

Carbon Area	25%	$411,799	$939,959	$530,231	$348,590	$437,771	$574,370
$469,245	$117,910	$427,151

	50%	$413,612	$942,075	$532,430	$349,944	$439,718	$576,566	$471,289
$118,097	$428,994

	75%	$415,170	$943,500	$534,274	$351,093	$441,388	$578,371	$473,029
$118,269	$430,562

Carbon Mobile	25%	$313,015	$716,951	$402,850	$264,875	$332,821	$437,209
$356,854	$87,249	$321,096

	50%	$314,924	$720,884	$405,304	$266,422	$334,864	$439,824	$359,040
$87,595	$323,064

	75%	$316,611	$724,298	$407,472	$267,782	$336,670	$442,127	$360,971
$87,879	$324,801

Carbon EGU & Non-EGU	25%	$246,335	$564,407	$317,462	$208,430	$261,931
$344,128	$280,855	$67,400	$256,301

	50%	$249,580	$571,348	$321,609	$211,141	$265,384	$348,575	$284,545
$68,257	$259,698

	75%	$252,634	$577,878	$325,517	$213,682	$268,635	$352,765	$288,022
$69,033	$262,894

NH3 Area	25%	$21,209	$48,522	$27,298	$17,952	$22,549	$29,609	$24,175
$5,835	$21,936

	50%	$21,989	$50,257	$28,307	$18,606	$23,379	$30,690	$25,064	$6,044
$22,756

	75%	$22,746	$51,931	$29,286	$19,240	$24,185	$31,738	$25,927	$6,246
$23,552

NH3 Mobile	25%	$40,599	$92,353	$52,245	$34,434	$43,136	$56,510	$46,215
$12,347	$43,373

	50%	$45,211	$102,801	$58,178	$38,336	$48,038	$62,925	$51,466	$13,674
$48,231

	75%	$49,769	$113,106	$64,041	$42,193	$52,882	$69,262	$56,656	$14,986
$53,032

Nox EGU	25%	$4,645	$10,638	$5,971	$3,932	$4,939	$6,487	$5,295	$1,287
$4,765

	50%	$5,512	$12,617	$7,088	$4,667	$5,861	$7,696	$6,283	$1,534	$5,677

	75%	$6,375	$14,585	$8,200	$5,397	$6,778	$8,899	$7,266	$1,780	$6,584

Nox Mobile	25%	$6,726	$15,373	$8,657	$5,696	$7,150	$9,385	$7,665	$1,926
$7,062

	50%	$7,360	$16,802	$9,472	$6,232	$7,824	$10,265	$8,386	$2,113	$7,729

	75%	$7,984	$18,205	$10,274	$6,760	$8,487	$11,131	$9,096	$2,297	$8,386

Nox NEGU	25%	$4,075	$9,324	$5,245	$3,451	$4,332	$5,688	$4,644	$1,155
$4,255

	50%	$4,635	$10,600	$5,966	$3,925	$4,928	$6,469	$5,282	$1,316	$4,843

	75%	$5,191	$11,864	$6,682	$4,395	$5,518	$7,243	$5,915	$1,475	$5,427

Sox Area	25%	$24,358	$55,941	$31,297	$20,600	$25,905	$34,064	$27,783
$6,643	$24,626

	50%	$25,314	$58,119	$32,529	$21,407	$26,921	$35,398	$28,873	$6,903
$25,615

	75%	$26,252	$60,254	$33,739	$22,199	$27,920	$36,707	$29,943	$7,158
$26,586

Sox EGU	25%	$44,482	$101,884	$57,280	$37,615	$47,303	$62,148	$50,723
$11,997	$45,899

	50%	$45,208	$103,402	$58,225	$38,202	$48,081	$63,149	$51,557	$12,130
$46,667

	75%	$45,889	$104,817	$59,115	$38,748	$48,811	$64,088	$52,339	$12,241
$47,389

Sox NEGU	25%	$29,075	$66,713	$37,402	$24,590	$30,921	$40,647	$33,160
$7,866	$29,545

	50%	$29,752	$68,230	$38,279	$25,156	$31,642	$41,590	$33,934	$8,037
$30,252

	75%	$30,411	$69,696	$39,133	$25,706	$32,344	$42,506	$34,686	$8,205
$30,942

VOC	25%	$590	$1,352	$760	$499	$627	$824	$673	$168	$604

	50%	$725	$1,659	$934	$613	$770	$1,012	$826	$206	$745

	75%	$858	$1,965	$1,106	$727	$913	$1,198	$978	$244	$885



Table 2: Estimated PM2.5 Benefit per Ton for the Year 2015 (7% Discount
Rate)

Source/Pollutant Combination	% Reduction	Pope et al.	Laden et al.	Expert
A	Expert B	Expert C

Carbon Area	25%	$228,199	$485,259	$686,905	$530,801	$524,727

	50%	$222,867	$472,494	$689,048	$532,808	$526,766

	75%	$218,105	$460,988	$690,704	$534,455	$528,454

Carbon Mobile	25%	$165,207	$351,887	$523,347	$403,083	$399,318

	50%	$163,273	$347,384	$526,361	$405,486	$401,708

	75%	$160,837	$341,763	$529,000	$407,603	$403,813

Carbon EGU & Non-EGU	25%	$139,534	$298,613	$411,953	$318,264	$314,289

	50%	$139,627	$298,443	$417,162	$322,380	$318,361

	75%	$138,947	$296,587	$422,066	$326,257	$322,195

NH3 Area	25%	$11,643	$24,816	$35,431	$27,351	$27,045

	50%	$11,728	$24,948	$36,713	$28,359	$28,033

	75%	$11,784	$25,015	$37,954	$29,338	$28,992

NH3 Mobile	25%	$26,457	$56,422	$67,540	$52,558	$51,649

	50%	$29,130	$62,080	$75,195	$58,506	$57,512

	75%	$31,801	$67,726	$82,752	$64,380	$63,304

Nox EGU	25%	$2,438	$5,187	$7,765	$5,984	$5,925

	50%	$2,947	$6,271	$9,211	$7,105	$7,030

	75%	$3,457	$7,359	$10,650	$8,220	$8,129

Nox Mobile	25%	$3,960	$8,457	$11,228	$8,709	$8,573

	50%	$4,320	$9,216	$12,277	$9,526	$9,378

	75%	$4,665	$9,939	$13,308	$10,331	$10,170

Nox NEGU	25%	$2,362	$5,045	$6,808	$5,264	$5,196

	50%	$2,686	$5,736	$7,741	$5,988	$5,909

	75%	$3,009	$6,422	$8,666	$6,706	$6,617

Sox Area	25%	$12,002	$25,569	$40,802	$31,285	$31,105

	50%	$12,487	$26,602	$42,395	$32,517	$32,323

	75%	$12,884	$27,435	$43,959	$33,727	$33,518

Sox EGU	25%	$22,918	$48,831	$74,383	$57,343	$56,757

	50%	$21,203	$44,946	$75,541	$58,274	$57,671

	75%	$19,207	$40,474	$76,625	$59,147	$58,528

Sox NEGU	25%	$14,424	$30,709	$48,675	$37,388	$37,118

	50%	$14,253	$30,289	$49,794	$38,263	$37,979

	75%	$14,101	$29,911	$50,879	$39,115	$38,816

VOC	25%	$308	$656	$987	$761	$753

	50%	$387	$825	$1,211	$935	$924

	75%	$466	$992	$1,434	$1,108	$1,095



Table 2 Continued: Estimated PM2.5 Benefit per Ton for the Year 2015 (7%
Discount Rate)

Source/Pollutant Combination	% Reduction	Expert D	Expert E	Expert F
Expert G	Expert H	Expert I	Expert J	Expert K	Expert L

Carbon Area	25%	$373,022	$848,711	$479,688	$316,093	$396,414	$519,443
$424,761	$108,330	$386,849

	50%	$374,626	$850,588	$481,640	$317,283	$398,139	$521,392	$426,573
$108,469	$388,480

	75%	$376,006	$851,848	$483,277	$318,294	$399,619	$522,993	$428,117
$108,601	$389,868

Carbon Mobile	25%	$283,462	$647,269	$364,372	$240,104	$301,301	$395,318
$322,946	$80,125	$290,740

	50%	$285,171	$650,801	$366,572	$241,488	$303,130	$397,663	$324,904
$80,426	$292,503

	75%	$286,681	$653,865	$368,515	$242,703	$304,746	$399,726	$326,634
$80,672	$294,057

Carbon EGU & Non-EGU	25%	$223,062	$509,535	$287,123	$188,923	$237,109
$311,140	$254,152	$61,904	$232,038

	50%	$225,995	$515,796	$290,868	$191,374	$240,229	$315,155	$257,487
$62,685	$235,107

	75%	$228,751	$521,684	$294,394	$193,669	$243,163	$318,935	$260,624
$63,390	$237,992

NH3 Area	25%	$19,209	$43,809	$24,693	$16,275	$20,416	$26,774	$21,880
$5,362	$19,864

	50%	$19,914	$45,373	$25,604	$16,867	$21,166	$27,750	$22,683	$5,553
$20,604

	75%	$20,598	$46,883	$26,488	$17,440	$21,894	$28,697	$23,462	$5,737
$21,324

NH3 Mobile	25%	$36,807	$83,419	$47,295	$31,255	$39,092	$51,137	$41,865
$11,361	$39,305

	50%	$40,985	$92,854	$52,664	$34,793	$43,531	$56,939	$46,619	$12,581
$43,705

	75%	$45,114	$102,159	$57,969	$38,291	$47,919	$62,671	$51,317	$13,787
$48,053

Nox EGU	25%	$4,207	$9,605	$5,401	$3,565	$4,472	$5,866	$4,793	$1,183
$4,315

	50%	$4,993	$11,392	$6,412	$4,231	$5,306	$6,960	$5,687	$1,410	$5,141

	75%	$5,775	$13,169	$7,418	$4,894	$6,137	$8,048	$6,577	$1,636	$5,962

Nox Mobile	25%	$6,094	$13,881	$7,833	$5,166	$6,475	$8,488	$6,939	$1,770
$6,395

	50%	$6,667	$15,172	$8,569	$5,652	$7,085	$9,284	$7,591	$1,941	$6,999

	75%	$7,233	$16,438	$9,295	$6,130	$7,686	$10,067	$8,235	$2,111	$7,595

Nox NEGU	25%	$3,692	$8,419	$4,745	$3,129	$3,923	$5,144	$4,204	$1,061
$3,853

	50%	$4,199	$9,571	$5,397	$3,559	$4,462	$5,850	$4,782	$1,209	$4,386

	75%	$4,702	$10,713	$6,045	$3,986	$4,997	$6,551	$5,355	$1,356	$4,915

Sox Area	25%	$22,051	$50,497	$28,300	$18,667	$23,444	$30,793	$25,136
$6,096	$22,293

	50%	$22,916	$52,462	$29,414	$19,397	$24,364	$31,998	$26,121	$6,334
$23,187

	75%	$23,765	$54,389	$30,508	$20,114	$25,267	$33,181	$27,089	$6,567
$24,066

Sox EGU	25%	$40,272	$91,971	$51,799	$34,087	$42,813	$56,183	$45,893
$11,014	$41,548

	50%	$40,921	$93,334	$52,646	$34,612	$43,509	$57,080	$46,639	$11,129
$42,236

	75%	$41,529	$94,603	$53,441	$35,098	$44,161	$57,920	$47,339	$11,225
$42,880

Sox NEGU	25%	$26,323	$60,222	$33,822	$22,284	$27,985	$36,745	$30,002
$7,221	$26,746

	50%	$26,934	$61,589	$34,613	$22,794	$28,636	$37,596	$30,700	$7,377
$27,384

	75%	$27,529	$62,911	$35,384	$23,291	$29,269	$38,422	$31,379	$7,529
$28,007

VOC	25%	$534	$1,221	$688	$453	$568	$745	$609	$154	$547

	50%	$656	$1,498	$845	$556	$697	$915	$748	$189	$675

	75%	$777	$1,774	$1,001	$659	$826	$1,084	$886	$224	$802



Table 3: Estimated PM2.5 Benefit per Ton for the Year 2030 (3% Discount
Rate)

Source/Pollutant Combination	% Reduction	Pope et al.	Laden et al.	Expert
A	Expert B	Expert C

Carbon Area	25%	$374,102	$806,534	$1,148,838	$885,380	$875,257

	50%	$365,490	$785,694	$1,152,611	$888,915	$878,847

	75%	$357,521	$766,298	$1,155,533	$891,814	$881,815

Carbon Mobile	25%	$270,945	$585,078	$876,843	$673,635	$667,342

	50%	$267,847	$577,787	$881,847	$677,638	$671,324

	75%	$263,826	$568,439	$886,224	$681,162	$674,833

Carbon EGU & Non-EGU	25%	$226,513	$490,917	$682,398	$525,889	$519,312

	50%	$226,729	$490,822	$691,088	$532,747	$526,094

	75%	$225,690	$487,973	$699,291	$539,224	$532,500

NH3 Area	25%	$18,799	$40,609	$58,096	$44,749	$44,232

	50%	$18,949	$40,860	$60,234	$46,427	$45,878

	75%	$19,055	$41,012	$62,304	$48,057	$47,476

NH3 Mobile	25%	$43,186	$93,336	$112,541	$87,313	$85,799

	50%	$47,554	$102,707	$125,297	$97,195	$95,541

	75%	$51,916	$112,050	$137,888	$106,956	$105,166

Nox EGU	25%	$3,954	$8,524	$12,898	$9,913	$9,817

	50%	$4,784	$10,319	$15,302	$11,773	$11,649

	75%	$5,618	$12,121	$17,694	$13,622	$13,471

Nox Mobile	25%	$6,509	$14,080	$18,741	$14,503	$14,272

	50%	$7,107	$15,358	$20,507	$15,876	$15,623

	75%	$7,678	$16,571	$22,243	$17,228	$16,953

Nox NEGU	25%	$3,857	$8,346	$11,328	$8,738	$8,624

	50%	$4,390	$9,496	$12,886	$9,943	$9,812

	75%	$4,920	$10,638	$14,431	$11,139	$10,990

Sox Area	25%	$19,670	$42,486	$68,134	$52,126	$51,818

	50%	$20,463	$44,195	$70,772	$54,161	$53,831

	75%	$21,110	$45,573	$73,360	$56,160	$55,807

Sox EGU	25%	$37,315	$80,580	$123,300	$94,841	$93,856

	50%	$34,477	$74,125	$125,262	$96,420	$95,409

	75%	$31,155	$66,648	$127,106	$97,910	$96,874

Sox NEGU	25%	$23,605	$50,959	$81,155	$62,196	$61,739

	50%	$23,310	$50,241	$83,028	$63,659	$63,179

	75%	$23,064	$49,630	$84,843	$65,083	$64,577

VOC	25%	$501	$1,080	$1,635	$1,257	$1,244

	50%	$630	$1,361	$2,009	$1,546	$1,529

	75%	$759	$1,638	$2,380	$1,833	$1,812



Table 3 Continued: Estimated PM2.5 Benefit per Ton for the Year 2030 (3%
Discount Rate)

Source/Pollutant Combination	% Reduction	Expert D	Expert E	Expert F
Expert G	Expert H	Expert I	Expert J	Expert K	Expert L

Carbon Area	25%	$619,350	$1,421,795	$799,196	$523,320	$658,809	$866,344
$706,626	$172,712	$642,217

	50%	$622,201	$1,425,132	$802,637	$525,475	$661,863	$869,783	$709,828
$173,097	$645,113

	75%	$624,645	$1,427,399	$805,517	$527,299	$664,477	$872,605	$712,550
$173,438	$647,570

Carbon Mobile	25%	$471,644	$1,086,166	$608,238	$398,407	$501,776
$660,585	$538,338	$128,135	$483,593

	50%	$474,509	$1,092,010	$611,910	$400,734	$504,839	$664,493	$541,613
$128,676	$486,542

	75%	$477,041	$1,097,073	$615,152	$402,780	$507,548	$667,931	$544,506
$129,127	$489,144

Carbon EGU & Non-EGU	25%	$366,975	$845,347	$473,914	$309,967	$390,430
$514,053	$418,891	$97,812	$381,639

	50%	$371,848	$855,805	$480,149	$314,034	$395,617	$520,741	$424,437
$99,081	$386,738

	75%	$376,445	$865,661	$486,038	$317,858	$400,513	$527,056	$429,673
$100,239	$391,549

NH3 Area	25%	$31,279	$71,944	$40,351	$26,429	$33,274	$43,784	$35,694
$8,398	$32,372

	50%	$32,449	$74,556	$41,866	$27,410	$34,520	$45,410	$37,029	$8,708
$33,603

	75%	$33,587	$77,080	$43,339	$28,362	$35,731	$46,988	$38,327	$9,007
$34,800

NH3 Mobile	25%	$60,823	$139,264	$78,471	$51,479	$64,668	$84,937	$69,334
$17,983	$64,953

	50%	$67,732	$155,010	$87,382	$57,315	$72,016	$94,578	$77,212	$19,919
$72,230

	75%	$74,562	$170,542	$96,187	$63,082	$79,280	$104,101	$84,998	$21,834
$79,420

Nox EGU	25%	$6,940	$15,978	$8,941	$5,865	$7,383	$9,718	$7,920	$1,879
$7,114

	50%	$8,237	$18,954	$10,615	$6,961	$8,762	$11,531	$9,399	$2,239	$8,477

	75%	$9,527	$21,912	$12,281	$8,051	$10,134	$13,335	$10,871	$2,597	$9,833

Nox Mobile	25%	$10,098	$23,207	$13,026	$8,536	$10,741	$14,128	$11,521
$2,823	$10,609

	50%	$11,057	$25,383	$14,262	$9,346	$11,761	$15,465	$12,614	$3,099
$11,619

	75%	$12,003	$27,518	$15,480	$10,144	$12,767	$16,780	$13,692	$3,372
$12,615

Nox NEGU	25%	$6,099	$14,031	$7,867	$5,156	$6,488	$8,537	$6,960	$1,686
$6,368

	50%	$6,940	$15,959	$8,953	$5,866	$7,382	$9,713	$7,919	$1,922	$7,252

	75%	$7,775	$17,869	$10,030	$6,571	$8,270	$10,879	$8,871	$2,156	$8,129

Sox Area	25%	$36,586	$84,444	$47,093	$30,892	$38,930	$51,294	$41,776
$9,746	$36,991

	50%	$38,009	$87,702	$48,931	$32,091	$40,445	$53,285	$43,401	$10,124
$38,463

	75%	$39,408	$90,897	$50,737	$33,269	$41,933	$55,240	$44,997	$10,496
$39,909

Sox EGU	25%	$66,319	$152,681	$85,573	$55,989	$70,564	$92,898	$75,710
$17,447	$68,447

	50%	$67,429	$154,986	$87,013	$56,889	$71,752	$94,422	$76,981	$17,663
$69,620

	75%	$68,476	$157,141	$88,373	$57,733	$72,873	$95,859	$78,181	$17,851
$70,727

Sox NEGU	25%	$43,603	$100,555	$56,200	$36,816	$46,395	$61,113	$49,783
$11,508	$44,313

	50%	$44,623	$102,844	$57,522	$37,668	$47,482	$62,535	$50,949	$11,765
$45,379

	75%	$45,615	$105,057	$58,810	$38,497	$48,540	$63,915	$52,083	$12,016
$46,418

VOC	25%	$879	$2,025	$1,135	$743	$935	$1,231	$1,003	$244	$900

	50%	$1,081	$2,488	$1,395	$913	$1,150	$1,513	$1,233	$300	$1,111

	75%	$1,281	$2,948	$1,654	$1,083	$1,363	$1,794	$1,462	$356	$1,321

Table 4: Estimated PM2.5 Benefit per Ton for the Year 2030 (7% Discount
Rate)

Source/Pollutant Combination	% Reduction	Pope et al.	Laden et al.	Expert
A	Expert B	Expert C

Carbon Area	25%	$339,651	$729,123	$1,037,420	$800,136	$791,019

	50%	$331,858	$710,316	$1,040,780	$803,282	$794,215

	75%	$324,649	$692,815	$1,043,382	$805,862	$796,856

Carbon Mobile	25%	$245,995	$528,920	$791,700	$608,680	$603,012

	50%	$243,192	$522,341	$796,194	$612,272	$606,586

	75%	$239,557	$513,907	$800,122	$615,432	$609,731

Carbon EGU & Non-EGU	25%	$205,525	$443,661	$616,119	$475,159	$469,235

	50%	$205,731	$443,588	$623,958	$481,347	$475,355

	75%	$204,803	$441,029	$631,354	$487,189	$481,133

NH3 Area	25%	$17,066	$36,709	$52,459	$40,437	$39,972

	50%	$17,204	$36,938	$54,387	$41,952	$41,458

	75%	$17,302	$37,078	$56,255	$43,423	$42,899

NH3 Mobile	25%	$39,202	$84,370	$101,667	$78,945	$77,582

	50%	$43,168	$92,841	$113,186	$87,877	$86,387

	75%	$47,127	$101,287	$124,558	$96,699	$95,086

Nox EGU	25%	$3,591	$7,708	$11,647	$8,959	$8,872

	50%	$4,345	$9,330	$13,818	$10,639	$10,527

	75%	$5,102	$10,959	$15,977	$12,311	$12,175

Nox Mobile	25%	$5,908	$12,727	$16,925	$13,108	$12,900

	50%	$6,450	$13,882	$18,519	$14,349	$14,121

	75%	$6,969	$14,979	$20,087	$15,570	$15,323

Nox NEGU	25%	$3,501	$7,544	$10,230	$7,897	$7,794

	50%	$3,985	$8,583	$11,637	$8,986	$8,868

	75%	$4,466	$9,615	$13,032	$10,067	$9,933

Sox Area	25%	$17,860	$38,409	$61,509	$47,091	$46,815

	50%	$18,579	$39,954	$63,890	$48,930	$48,632

	75%	$19,167	$41,200	$66,227	$50,735	$50,417

Sox EGU	25%	$33,872	$72,839	$111,315	$85,683	$84,796

	50%	$31,311	$67,020	$113,077	$87,100	$86,189

	75%	$28,311	$60,278	$114,730	$88,435	$87,501

Sox NEGU	25%	$21,434	$46,070	$73,266	$56,191	$55,779

	50%	$21,170	$45,425	$74,954	$57,510	$57,077

	75%	$20,949	$44,876	$76,590	$58,794	$58,338

VOC	25%	$455	$977	$1,476	$1,136	$1,124

	50%	$572	$1,231	$1,814	$1,397	$1,381

	75%	$689	$1,481	$2,149	$1,657	$1,637



Table 4 Continued: Estimated PM2.5 Benefit per Ton for the Year 2030 (7%
Discount Rate)

Source/Pollutant Combination	% Reduction	Expert D	Expert E	Expert F
Expert G	Expert H	Expert I	Expert J	Expert K	Expert L

Carbon Area	25%	$560,535	$1,283,260	$722,514	$474,045	$596,073	$782,991
$639,140	$158,269	$581,130

	50%	$563,065	$1,286,228	$725,576	$475,948	$598,787	$786,050	$641,987
$158,578	$583,701

	75%	$565,235	$1,288,239	$728,138	$477,560	$601,110	$788,561	$644,407
$158,854	$585,883

Carbon Mobile	25%	$426,756	$980,227	$549,780	$360,795	$453,895	$596,927
$486,825	$117,373	$437,518

	50%	$429,323	$985,478	$553,074	$362,877	$456,640	$600,433	$489,761
$117,847	$440,161

	75%	$431,590	$990,024	$555,980	$364,706	$459,065	$603,516	$492,353
$118,240	$442,490

Carbon EGU & Non-EGU	25%	$332,032	$762,880	$428,347	$280,688	$353,157
$464,498	$378,790	$89,610	$345,240

	50%	$336,434	$772,311	$433,975	$284,363	$357,841	$470,535	$383,798
$90,765	$349,844

	75%	$340,582	$781,195	$439,287	$287,815	$362,259	$476,230	$388,522
$91,816	$354,185

NH3 Area	25%	$28,306	$64,931	$36,476	$23,937	$30,102	$39,569	$32,282
$7,698	$29,291

	50%	$29,363	$67,287	$37,844	$24,824	$31,228	$41,037	$33,488	$7,980
$30,402

	75%	$30,391	$69,563	$39,174	$25,685	$32,322	$42,460	$34,659	$8,253
$31,483

NH3 Mobile	25%	$55,087	$125,735	$70,981	$46,671	$58,550	$76,806	$62,753
$16,503	$58,807

	50%	$61,341	$139,948	$79,038	$51,958	$65,199	$85,520	$69,879	$18,278
$65,391

	75%	$67,523	$153,967	$86,999	$57,183	$71,772	$94,127	$76,923	$20,033
$71,898

Nox EGU	25%	$6,281	$14,421	$8,083	$5,313	$6,680	$8,783	$7,164	$1,722
$6,437

	50%	$7,455	$17,107	$9,597	$6,305	$7,928	$10,421	$8,502	$2,052	$7,671

	75%	$8,622	$19,777	$11,103	$7,293	$9,169	$12,052	$9,833	$2,381	$8,898

Nox Mobile	25%	$9,140	$20,946	$11,777	$7,734	$9,719	$12,770	$10,422
$2,588	$9,600

	50%	$10,009	$22,911	$12,895	$8,467	$10,642	$13,978	$11,411	$2,841
$10,514

	75%	$10,864	$24,838	$13,996	$9,190	$11,552	$15,167	$12,385	$3,091
$11,415

Nox NEGU	25%	$5,521	$12,664	$7,113	$4,671	$5,870	$7,716	$6,295	$1,546
$5,762

	50%	$6,282	$14,404	$8,094	$5,314	$6,680	$8,779	$7,163	$1,762	$6,562

	75%	$7,037	$16,128	$9,068	$5,953	$7,483	$9,833	$8,024	$1,976	$7,356

Sox Area	25%	$33,096	$76,199	$42,558	$27,967	$35,207	$46,343	$37,770
$8,922	$33,460

	50%	$34,383	$79,139	$44,219	$29,052	$36,576	$48,141	$39,238	$9,267
$34,791

	75%	$35,647	$82,021	$45,851	$30,118	$37,921	$49,906	$40,681	$9,607
$36,099

Sox EGU	25%	$59,995	$137,777	$77,336	$50,691	$63,818	$83,933	$68,452
$15,978	$61,912

	50%	$60,989	$139,848	$78,627	$51,496	$64,883	$85,301	$69,592	$16,167
$62,962

	75%	$61,925	$141,781	$79,845	$52,249	$65,885	$86,587	$70,666	$16,330
$63,952

Sox NEGU	25%	$39,445	$90,739	$50,790	$33,332	$41,959	$55,215	$45,011
$10,539	$40,084

	50%	$40,365	$92,802	$51,982	$34,101	$42,940	$56,497	$46,063	$10,771
$41,046

	75%	$41,260	$94,796	$53,144	$34,849	$43,894	$57,742	$47,085	$10,999
$41,983

VOC	25%	$796	$1,828	$1,026	$673	$846	$1,113	$908	$224	$815

	50%	$978	$2,246	$1,261	$827	$1,040	$1,368	$1,115	$275	$1,006

	75%	$1,159	$2,661	$1,495	$981	$1,233	$1,621	$1,322	$326	$1,196

Discussion

The benefit per ton estimates above vary according to three factors. The
first source of variability is attributable to the PM2.5 mortality
estimate used to calculate total benefits. Consistent with the results
of the PM2.5 RIA, the PM2.5-related benefits derived using the Laden et
al. (2006) mortality estimate are roughly double those estimates based
on Pope et al. (2002). The PM2.5-related benefits calculated using the
12 expert-derived functions also vary significantly. 

The second source of variability among the estimates is due to the
different potential for a given ton of each of the 12 source/sector
combinations to form PM2.5 in the atmosphere. For example, carbonaceous
particles emitted directly from mobile sources tend to have a great
potential to form PM2.5 in the atmosphere than do volatile organic
compounds. As such, the monetized benefits of abating a ton of mobile
source carbonaceous particles is significantly greater than that of
reducing a ton of volatile organic compounds. 

Finally, the benefit per ton estimates calculated for a population year
of 2030 are significantly higher than those calculated for a population
year of 2015. This is consistent with the population growth estimated in
the Woods & Poole projections that BenMAP uses to calculate future-year
population exposure. 

There are several key limitations and uncertainties associated with
these benefit per ton estimates:

These estimates are regional averages. As such, they do not reflect any
spatial variability in the incremental PM2.5 benefits per ton of PM2.5
precursor abated. For this reason, there are special uncertainties
incurred when using these metrics to estimate the local-scale benefits
of emission reductions.

The benefit per ton metrics contain each of the uncertainties inherent
in a PM2.5 benefits analysis. As discussed in the PM2.5 NAAQS RIA (Table
5.5), there are a variety of uncertainties associated with calculating
PM benefits; these uncertainties are propagated through to the benefit
per ton estimates included in this TSD.

These estimates omit certain benefits categories. Reductions in PM2.5
precursors may provide visibility benefits, which are not expressed in
the benefit per ton metrics. Certain unquantified benefit categories,
described fully in the PM2.5 NAAQS RIA are also omitted.

References

Abt Associates, Incorporated. Environmental Benefits Mapping and
Analysis Program (Version 2.4). Prepared for Environmental Protection
Agency, Office of Air Quality Planning and Standards, Air Benefits and
Cost group. Research Triangle Park, NC.  2005.

Industrial Economics, Incorporated (IEc).  August 2006.  Expanded Expert
Judgment Assessment of the Concentration-Response Relationship Between
PM2.5 Exposure and Mortality. Peer Review Draft. Prepared for: Office of
Air Quality Planning and Standards, U.S. Environmental Protection
Agency, Research Triangle Park, NC.

Laden, F., J. Schwartz, F.E. Speizer, and D.W. Dockery. 2006. Reduction
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Pope, C.A., III, R.T. Burnett, M.J. Thun, E.E. Calle, D. Krewski, K.
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http://www.epa.gov/ttn/ecas/ria.html  [accessed 10 March 2008]. 

 Abt Associates, Incorporated. Environmental Benefits Mapping and
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