### ES

- 1

EXECUTIVE SUMMARY

Overview In setting primary national ambient air quality standards (NAAQS), the EPA’s responsibility under the law is to establish standards that protect public health. The Clean Air Act (the Act) requires the EPA, for each criteria pollutant, to set a standard tha t protects public health with “an adequate margin of safety.” As interpreted by the Agency and the courts, the Act requires the EPA to base this decision on health considerations only; economic factors cannot be considered. The prohibition against conside ring cost in the setting of the primary air quality standards does not mean that costs, benefits or other economic considerations are unimportant. The Agency believes that consideration of costs and benefits is an essential decision

- making tool
for the eff

icient implementation of these standards. The impacts of costs, benefits, and efficiency are considered by the States when they make decisions regarding what timelines, strategies, and policies are appropriate for their circumstances.

The EPA is proposing to revise the level of the ozone NAAQS to within a range of 65 ppb to 70 ppb and is soliciting comment on alternative standard levels below 65 ppb, as low as 60 ppb. T he EPA is also proposing to revise the level of the secondary standard to within the

ran ge proposed for the primary standard of 65 ppb to 70 ppb to provide increased protection against vegetation

- related effects on public welfare. 1 

### The EPA performed an illustrative analysis of the potential costs, human health benefits, and welfare co

- benefi ts of nationally attaining primary alternative ozone standard levels and did not estimate any incremental costs and benefits associated with attaining a revised secondary standard. Per Executive Order 12866 and the guidelines of OMB Circular A

- 4, this Reg ulatory Impact Analysis (RIA) presents the analyses of the following alternative standard levels

-- 70 ppb, 65 ppb, and 60 ppb. The cost and benefit estimates below are calculated incremental to a 2025 baseline that incorporates air quality improvements a chieved through the projected implementation of existing regulations and full attainment of the existing ozone NAAQS (75 ppb). The 2025 baseline reflects, among other

1 As an initial matter, the EPA is proposing that ambient ozone concentrations in terms of a three

- year average W126 index value within the range from 13 parts per million

- hours (ppm

- hours) to 17 ppm

- hours would provide the requisite p rotection against known or anticipated adverse effects to the public welfare, which data analyses indicate would provide air quality in terms of three

- year average W126 index values of a range at or below 13 ppm

- hours to 17 ppm

- hours. Data analyses also i ndicate that actions taken to attain a standard in the range of 65 ppb to 70 ppb would also improve air quality as measured by the W126 metric.

### ES

- 2

existing regulations, the Mercury and Air Toxics Standard, the Clean Air Interstate Rule , the Tier 3 Motor Vehicle Emission and Fuel Standards, and adjustments for the Clean Power Plan, all of which will help many areas move toward attainment of the existing ozone standard (see Chapter 3, Section 3.1.3 for additional information).

In this R IA w e present the primary costs and benefits estimates for 2025. We assume that potential nonattainment areas everywhere in the U.S., excluding California, will be designated such that they are required to reach attainment by 2025, and we developed our

pr ojected baselines for emissions, air quality, and populations for 2025.

The EPA will likely finalize designations for a revised ozone NAAQS in late
2017. Depending on the precise timing of the effective date of those designations, nonattainment
areas cl assified as Marginal will likely have to attain in either late 2020 or early
2021. Nonattainment areas classified as Moderate will likely have to attain in either late 2023 or early 2024. If a Moderate nonattainment area qualifies for two 1

- year extensio ns, the area may
have as late as 2026 to attain. Lastly, Serious nonattainment areas will likely have to attain in late 2026 or early 2027. We selected 2025 as the primary year of analysis because most areas of the U.S. will likely be required to meet a revised ozone standard by 2025 and because it provided a good representation of the remaining air quality concerns that Moderate nonattainment areas would face; states with areas classified as Moderate and higher are required to develop
attainment demonstr ation plans for those nonattainment areas.

In estimating the incremental costs and benefits of potential alternative standards, we recognize that there are several areas that are not required to meet the existing ozone standard by
2025. The Clean Air Act allows areas with more significant air quality problems to take additional time to reach the existing standard. Several areas in California are not required to meet the existing standard by 2025 and may not be required to meet a revised standard until

som etime between 2032 and 2038. 2 

### We were not able to project emissions and air quality beyond 2025 for California, however, we adjusted baseline air quality to reflect mobile source

2 The EPA will likely finalize designations for a revised ozone NAAQS in late 2017. Depending on the precise t iming of the effective date of those designations, nonattainment areas classified as Severe 15 will likely have to attain sometime between late 2032 and early 2033 and nonattainment areas classified as Extreme will likely have to attain sometime between la te 2037 and early 2038.

### ES

- 3

emissions reductions for California that would occur between 2025 and 2030; these emissions reductions were the result of mobile source regulations expected to be fully implemented by
2030. W hile there is uncertainty about the precise timing of e missions reductions and related
costs for California , we assume costs occur through 2 038. In addition, we model benefits for California using projected population demographics for 2038.

Because of the different timing for incurring costs and accruing benefits and f or ease of discussion throughout the analyses
, we refer to the different time periods for potential attainment as 2025 and post

- 2025 to reflect that (1) we did not project emissions and air quality for any year other than 2025; (2) for California, emissions controls and associated costs are assumed to occur through 2038; and ( 3) for California benefits are modeled using population demographics in
2038

. I t is not straightforward to discount the post

- 2025 results for C alifornia to compare with
or add to the 2025 results for the rest of the U.S. W hile we estimate benefits using 2038 information, we do not have good information on precisely when the costs of control s will be
incurred

. Because of these differences in timing related to Ca lifornia attaining a revised standard, the supplemental separate costs and benefits estimates for post

- 2025 should not be added to the primary estimates for 2025.

ES.1 Overview of Analytical Approach This RIA consists of multiple analyses including an assessment of the nature and sources of ambient ozone (Chapter 2

– D efining the Air Quality Problem); estimates of current and future emissions of relevant precursors that contribute to the problem; air quality analyses of baseline and alternative control strategies (Chapter 3

– Air Quality Modeling and Analysis); developm ent of illustrative control strategies to attain the primary alternative standard levels (Chapter 4

– Control Strategies and Emissions Reductions); estimates of the incremental benefits of attaining the primary alternative standard levels ( Chapter 5

– Huma n Health Benefits ) ; a qualitative discussion of the welfare co

- benefits of attaining the primary alternative standard
levels (Chapter 6

– Welfare Co

- Benefits of the Primary Standard); estimates of the incremental costs of attaining the primary alternative standard levels ( Chapter 7

– Engineering Cost Analysis and Economic Impacts ); a comparison and discussion of the benefits and costs (Chapter 8

– Comparison of Costs and Benefits); an analysis of the impacts of the relevant statutory and executive orders (C hapter 9

– Statutory and Executive Order Impact Analysis); and a discussion

### ES

- 4

of the theoretical framework used to analyze regulation

- induced employment impacts, as well as
information on employment related to installation of NOx controls on coal and gas

- fir ed electric generating units, industrial boilers, and cement kilns (Chapter 10

– Qualitative Discussion of Employment Impacts of Air Quality).

Because States are ultimately responsible for implementing strategies to meet revised standards, this RIA provide s insights and analysis of a limited number of illustrative control strategies that states might adopt to meet a revised standard. The goal of this RIA is to provide
estimates of the costs and benefits of the illustrative attainment strateg ies to the meet each alternative standard level. The flowchart below (Figure ES

- 1) outlines the analytical steps taken
to illustrate attainment with the potential alternative standard levels, and the following
d iscussion, by primary flowchart section, describes the steps taken.

Figure ES

- 1. Analytical Flowchart for Primary Standards Analyses

### ES

- 5

ES.1.1 Establishing the Baseline
The future year base case reflects emissions projected from 2011 to 2025 and incorporates current state and federal programs, including the Tier 3 Motor Vehicle Emission and Fuel Standards (U.S. EPA, 2014a) (see Chapter 3, Section 3.1.3 for a discussion of the rules included in the base case). The base case does not include control programs specifically for the purpose of attaining the existing ozo ne standard (75 ppb). The baseline builds on the future year
base case and reflects the additional emissions reductions needed to reach attainment of the current ozone standard (75 ppb) , as well as adjustments for the Clean Power Plan (U.S. EPA, 2014b).

We p erformed a national scale air quality modeling analysis to estimate ozone
concentrations for the future base case year of 2025. To accomplish this, we modeled multiple emissions cases for 2025, including the 2025 base case and twelve 2025 emissions se nsitivity
simulations. The twelve emissions sensitivity simulations were used to develop ozone sensitivity factors (ppb/ton) from the modeled response of ozone to changes in NOx and VOC emissions from various sources and locations. These ozone sensitivity factors were then used to determine the amount of emissions reductions needed to reach the 2025 baseline and evaluate potential alternative standard levels of 70, 65, and 6 0 ppb incremental to the baseline. We used the
estimated emissions reductions need ed to reach each of these standard levels to analyze the costs
and benefits of alternative standard levels.

ES.1.2 Control Strategies and Emissions Reductions
The EPA analyzed illustrative control strategies that areas across the U.S. might employ

to att ain alternative revised primary ozone standard levels of 70, 65, and 60 ppb. The EPA analyzed the impact that additional emissions control technologies and measures, across numerous sectors, would have on predicted ambient ozone concentrations incremental to the baseline. These control measures, also referred to as known controls, are based on information available at the time of this analysis and include primarily end

- of

- pipe control technologies. In addition, to attain some of the alternative primary st andard levels analyzed, some areas needed additional emissions reductions beyond the known controls, and we refer to these as unknown controls (see Chapter 7, Section 7.2 for additional information).

### ES

- 6

Using average ozone response factors, we estimated the p ortion of the emissions reductions required to meet the baseline, including any additional emissions reductions beyond
known controls. We then estimated the emissions reductions incremental to the baseline that
were needed to meet the alternative standard levels of 7 0, 65, and 6 0 ppb. Costs of controls incremental to (i.e., over and above) the baseline emissions reductions are attributed to the costs of meeting the alternative standard levels. These emissions reductions can come from both specific known co ntrols , as well as unknown controls. The baseline shows that by 2025, while ozone air quality would be significantly better than today under current requirements, depending on the alternative standard level analyzed, several areas in the Eastern, Central, and Western U.S. would need to develop and adopt additional controls to attain alternative standard levels (see Chapter 4, Section 4.3).

ES.1.2.1 Emissions Reductions from Known Controls in 2025
Figure ES

- 2 shows the counties projected to exceed the alt ernative standard levels analyzed for 2025 for areas other than California. For the 70 ppb alternative standard level, emissions reductions were required for monitors in the Central and Northeast regions. For the 65 and 60 ppb alternative standard levels, emissions reductions were applied in all regions with projected baseline design values (DVs) above these levels. 3 

### For the 60 ppb alternative standard level, additional VOC emissions reductions were identified in Chicago because some sites in that

area exp erienced NO x 

### disbenefits, meaning that the regional NO x 

### emissions reductions resulted in ozone increases from below 60 ppb to above 60 ppb. Table s ES

- 1 through ES

- 3 show the
emission s reductions from known controls for th e alternative standard levels anal yzed.

3 A design value is a statistic that describes the air quality status of a given area relative to the level of the NAAQS. Design values are typically used to classify nonattainment areas, assess progress toward meeting the NAAQS, and develop control strategies.

### ES

- 7

Figure ES

- 2. Projected Ozone Design Values in the 2025 Baseline Scenario

### ES

- 8

Table ES

- 1

. Summary of Emission Reductions by Sector for Known Controls for 70 ppb

Proposed Alternative Standard Level for 2025, except California (1,000 tons/year) a Geograp hic Area Emissions Sector NO x VOC

East EGU 25

-

Non

- EGU Point 210 0.98 Nonpoint 260 54 Nonroad 5

- Total 490 55

West EGU

- - Non

- EGU Point

- - Nonpoint

- - Nonroad

- - Total

- -

a Estimates are rounded to two significant figures.



### Table ES

- 2

. Summary of Emission Reductions by Sector for Known Controls for 65 ppb

Proposed Alternative Standard Level for 2025

- except California (1,000 tons/year) a Geographic Area Emissions Sector NO x VOC

East EGU 170

-

Non

- EGU Point 410 3.6 Nonpoint 420 95 Nonroad 12

- Total 1,000 99

West EGU 36

- Non

- EGU Point 38 0.47 Nonpoint 37 6.6 Nonroad 1.3

- Total 110 7

a Estimates are rounded to two significant figures.



### Table ES

- 3

. Summary of Emission Reductions by Sector for Known Controls for 60 ppb

Alternative Standard Level for 2025

- except California (1,000 tons/year) a Geographic Area Emissions Sector NO x VOC

East EGU 170

-

Non

- EGU Point 410 4.2 Nonpoint 420 99 Nonroad 12

- Total 1,000 100

West EGU 62

-

Non

- EGU Point 48 0.47 Nonpoint 39 6.6 Nonroad 1.3

- Total 150 7

a Estimates are rounded to two significant figures.

### ES

- 9

ES

. 1 .2 .2 Emissions Reductions beyond Known Controls in 2025

There were several areas where known controls did not achieve enough emissions reductions to attain the proposed alternative standard levels of 70 and 65 as well as the more stringent alternative standard level of 60 ppb. To complete the analysis, the EPA then estimated
the additional e missions reductions beyond known controls needed to reach attainment (i.e., unknown controls). Table ES

- 4 shows the emissions reductions needed from unknown controls in 2025 for the U.S., except California, for the alternative standard levels analyzed.

Ta ble ES

- 4

. Summary of Emission s Reductions by Alternative Standard for Unknown

Controls for 2025

- except California (1,000 tons/year) a Region NO x VOC Proposed Alternative Standard Levels 70 ppb East West 150

- -

- 65 ppb East West 750

- -

- Alternative Standard Level 60 ppb East West 1,900 350 41

-



### ES.1.2.3 Emissions Reductions beyond Known Controls for Post

- 2025
Figure ES

- 3 shows the counties projected to exceed the alternative standard levels analyzed for the post

- 2025 analysis for California. For the California post

- 2025 alternative standard level analyses, all known controls were applied in the baseline, so inc remental
emissions reductions are from unknown controls. Table ES

- 5 shows the emissions reductions
needed from unknown controls for post

- 2025 for California for the alternative standard levels analyzed.

### ES

- 10

Figure ES

- 3. Projected Ozone Design Values in the post

- 2025 Baseline Scenario

Table ES

- 5

. Summary of Emissions Reductions by Alternative Standard Level for

Unknown Controls for post

- 2025

- California (1,000 tons/year) a

Region NO x VOC Proposed Alternative Standard Levels 70 ppb CA 53

- 65 ppb CA 110

- Alternative Standard Level 60 ppb CA 140

-

a Estimates are rounded to two significant figures.



### ES.1.3 Human Health Benefits
To estimate benefits, w e follow a “damage

- function” approach in calculating total benefits of the modeled changes in environmental quality. This approach estimates changes in individual health endpoints (specific effects that can be associated with changes in air quality)
and a ssigns values to those changes assuming independence of the values for those individual endpoints. Total benefits are calculated as the sum of the values for all non

- overlapping health endpoints. The “damage

- function” approach is the standard method for as sessing costs and benefits of environmental quality programs and has been used in several recent published analyses (Levy et al., 2009; Fann et al., 2012a; Tagaris et al., 2009).

### ES

- 11

To assess economic values in a damage

- function framework, the changes in
envi ronmental quality must be translated into effects on people or on the things that people value. In some cases, the changes in environmental quality can be directly valued, as is the case for changes in visibility. In other cases, such as for changes in ozo ne and PM, an impact analysis must first be conducted to convert air quality changes into effects that can be assigned dollar values. For the purposes of this RIA, the health impacts analysis is limited to those health effects that are directly linked to a mbient levels of air pollution and specifically to those linked to ozone
and PM 2.5


### .

Benefits estimates for ozone were generated using the damage function approach outlined above wherein potential changes in ambient ozone levels (associated with future atta inment of alternative standard levels) were explicitly modeled and then translated into reductions in the incidence of specific health endpoints. In generating ozone benefits estimates for the two
attainment timeframes considered in the RIA (2025 and post

- 2025), we used three distinct benefits simulations including one completed for 2025 and two completed for 2038. The way in which these three benefits simulations were used to generate estimates for the two time frames is
de tailed in Chapter 5, S ection 5.4.3

.
In contrast to ozone, we used a benefit

- per

- ton approach in modeling PM 2.5 

### co

- benefits. With this approach, we u s e the results of previous benefits analysis simulations focusing on
PM 2.5 

### to derive benefits

- per

- ton estimates for NOx. 4 

### We then combine the se dollar

- per

- ton estimates with projected reductions in NOx associated with meeting a given alternative standard
level to project cobenefits associated with PM 2.5 

### . We acknowledge increased uncertainty
associated with the dollar

- per

- ton approach for PM 2.5, 

### relative to explicitly modeling benefits using gridded PM 2.5 

### surfaces specific to the baseline and alternative standard levels (see Appendix 5A, Table 5A

- 1 for additional discussion).

In addition to ozone and PM 2.5 

### benefits, implementing emissions controls to reach some of
the alternative ozone standard level s would reduce other ambient pollutants. However, because
the method s used in this analysis to simulate attainment do not account for changes in ambient

4 In addition to dollar

- per

- ton estimates for NOx, we also used incidence

- per

- ton values (also for NOx) for specific health endpoints to generate incidence reduction estimates associated with the dollar benefits.

### ES

- 12

concentrations of other pollutants, we we re not able to quantify the co

- benefits of reduced exposure to these pollutants. In addition, due to data and methodology limitations, we were unable to estimate some anticipated health benefits associated with exposure to ozone and PM 2.5


### .

ES.1.4 Welfare C o

- Benefits of the Primary Standard

Section 109 of t he Clean Air Act defines welfare effects to include any non

- health effects, including direct economic damages in the form of lost productivity of crops and trees, indirect damages through alteration of eco system functions, indirect economic damages through the loss in value of recreational experiences or the existence value of important resources, and direct damages to property, either through impacts on material struc tures or by soiling of surfaces ( 42
U.S .C. 7409 )

. Ozone can affect ecological systems, leading to changes in the ecological

commu nity and influencing the diversity, health, and vigor of individual species (U.S. EPA, 2013). Ozone causes discernible injury to a wide array of vegetation (U.S. EP A, 2013). In terms of forest productivity and ecosystem diversity, ozone may be the pollutant with the greatest potential for region

- scale forest impacts (U.S. EPA, 2013). Studies have demonstrated repeatedly that ozone concentrations observed in polluted areas can have substantial impacts on plant function (De Steiguer et al,. 1990; Pye, 1988).

In this RIA, we are able to quantify only a small portion of the welfare impacts associated
with reductions in ozone concentrations to meet alternative ozone standa rds. Using a model of commercial agriculture and forest markets, we are able to analyze the effects on consumers and producers of forest and agricultural products of changes in the W126 index resulting from meeting alternative standards within the propose d range of 70 to 65 ppb, as well as a lower standard level of 60 ppb. We also assess the effects of those changes in commercial agricultural and forest yields on carbon sequestration and storage. This analysis provides limited quantitative
information on the welfare co

- benefits of meeting these alternative standards, focused only on one subset of ecosystem services. Commercial and non

- commercial forests provide a number of additional services, including medicinal uses, non

- commercial food and fiber produ ction, arts and crafts uses, habitat, recreational uses, and cultural uses for Native American tribes. A more complete discussion of these additional ecosystem services is provided in the final Welfare Risk and Exposure Assessment for Ozone (U.S. EPA, 201 4 c ).

### ES

- 13

ES.2 Results of Benefit

- Cost Analysis

Below in Table ES

- 6, we present the primary costs and benefits estimates for 2025 for all areas except California

. In addition, Tables 5

- 1 and 5

- 23 in Chapter 5 provide a breakdown of

ozone

- only and PM 2.5 

### - only be nefits , as well as total benefits at 3 percent

. We anticipate that
benefits and costs will likely begin occurring earlier, as states begin implementing control measures to show progress towards attainment. In these tables, ranges within the total benefits rows reflect variability in the studies upon which the estimates associated with premature mortality were derived. PM 2.5 

### co

- benefits account for approximately two

- thirds to three

- quarters of the estimated benefits, depending on the standard analyzed and on the choice of ozone and PM mortality functions used. In addition for 2025, Table ES

- 7 presents the numbers of premature deaths avoided for the alternative standard levels analyzed, as well as the other health
effects avoided. Table ES

- 8 p rovide s information on the costs by geographic region for the U.S., except California in 2025
, and Table ES

- 9 provides a regional breakdown of benefits for 2025

. In th e RIA we provide estimates of costs of emissions red uctions to attain the proposed standards in three regions

-- California, the rest of the western U.S., and the eastern U.S. In addition, we provide estimates of the benefits that accrue to each of these three regions resulting from (i) control strategies applied within the region, (ii) reductions in transport of ozone associated with emissions reductions in other regions, and (iii) the control strategies for which the regional cost estimates are generated. These benefits are not directly comparable to th e costs

o f control strategies in a region because the benefits include benefits not associated with those control strategies.
The net benefits of emissions reductions strategies in a specific region would be the
benefits of the emissions reductions occurring both within and outside of the region minus the
costs of the emissions reductions. Because the air quality modeling is done the national level, we do not estimate separately the nationwide benefits associated with the emissions reductions

occurr ing in any specific region. 5 

### As a result, we are only able to provide net benefits estimates
at the national level. The difference between the costs for a specific region and the benefits

5 For Cal ifornia, we provide separate estimates of the costs and nationwide estimates of benefits, so it is appropriate to calculate net benefits. As such, we provide net benefits for the post

- 2025 California analysis.

### ES

- 14

accruing to that region is not an estimate of net benefits of the emissions reductions in that region.

Table ES

- 6. Total Annual Costs a 

### and Benefits b a 

### for U.S., except California in 2025

(billions of 2011$, 7% Discount Rate) b
Proposed Alternative Standard Levels Alternative Standard Level 70 ppb 65 ppb 60 ppb Total Costs (7%) $3.9 $15 $39 Health Benefits (3%) c $6.9 to $14.0 $20 to $41 $37 to $75 Total Health Benefits (7%) c $6.4 to $13.0 $19 to $38 $34 to $70 Net Benefits (3%) $3.0 to $10.1 $5 to $26 ($2) to $36 Net Benefits (7%) $2.5 to $9.1 $4 to $23 ($5) to $31

a Engineering costs reflect 7% discount rate. We do not have a comprehensive data set to be able to calculate engineering costs at a 3% discount rate. b a Benefits are nationwide benefits of attainment everywhere except California. b EPA believes that providing comparisons of social costs and social benefits at 3 and 7 percent is appropriate. Estimating multiple years of costs and benefits is not possible for this RIA due to data and resource limitations. As a result, we provide a snapshot of cos ts and benefits in 2025, using the best available information to approximate social costs and social benefits recognizing uncertainties and limitations in those estimates.

c c The benefits range reflects the LOW and UPPER core estimates of short

- term ozone and long

- term PM mortality.



### EPA believes t

hat providing comparisons of social costs and social benefits at 3 and 7 percent is appropriate. Ideally, streams of social costs and social benefits over time would be estimated and the net present values of ea ch would be compared to determine net benefits of the illustrative attainment strategies. The three different uses of discounting in the RIA

– (i) construction of annualized engineering costs, (ii) adjusting the value of mortality risk for lags in
mortali ty risk decreases, and (iii) adjusting the cost of illness for non

- fatal heart attacks to adjust for lags in follow up costs

-- are all appropriate. Our estimates of net benefits are the approximations of the net value (in 2025) of benefits attributable to emissions reductions needed to attain just for the year 2025.

Table ES

- 7. Summary of Total Number of Annual Ozone and PM

- Related Premature

Mortalities and Premature Morbidity: 2025 National Benefits a

Proposed Alternative Standard Levels (95 th percentile confidence intervals) b Alternative Standard Level (95th percentile confidence intervals) 70 ppb 65 ppb 60 ppb Short

- term exposure

- related premature deaths avoided (all ages) (Ozone

– 2 studies) 200 to 340 (97 to 300 ) ( 180 to 490) 630 to 1,000 (310 to 940) (560 to 1,500) 1,100 to 1,900 (560 to 1,700) (1,000 to 2,800) Formatted Table

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### ES

- 15 Proposed Alternative Standard Levels (95 th percentile confidence intervals) b Alternative Standard Level (95th percentile confidence intervals) 70 ppb 65 ppb 60 ppb Long

- term exposure

- related premature deaths avoided (age 30+) (PM

– 2 studies) O 3 : 680 (230 to 1,100) PM 2.5 : 510 to 1,100 c O 3 : 2,100 (710 to 3,500) PM 2.5 : 1,400 to 3,300 c O 3 : 3,900 (1,300 to 6,400) PM 2.5 : 2,600 to 6,000 c Other health effects avoided d Non

- fatal heart attacks (age 18

- 99) (5 studies) PM 64 to 600 180 to 1,700 330 to 3,100 Respiratory hospital admissions (age 0

- 99) O3, PM 510 1,600 2,900 Cardiovascular hospital admissions (age 18

- 99) PM 180 530 950 Asthma emergency department visits (age 0

- 18) O3, PM 1,400 4,300 8,000 Acute bronchitis (age 8

- 12) PM 790 2,300 4,100 Asthma exacerbation (age 6

- 18) O3, PM 320,000 970,000 1,800,000 Lost work days (age 18

- 65) PM 65,000 180,000 340,000 Minor restricted activity days (age 18

- 65) O3, PM 1,300,000 3,900,000 7,300,000 Upper & lower respiratory symptoms (children) PM 25,000 70,000 130,000 School loss days O3 330,000 1,000,000 1,900,000

a Nationwide benefits of attainment everywhere except California. b We present a confidence interval in parentheses f or each study on short

- term or long

- term ozone

- related mortality.

c These estimates were generated using benefit

- per

- ton estimates and confidence intervals are not available. In general, the 95 th percentile confidence interval for the health impact function alone ranges from + 30 percent for mortality incidence based on Krewski et al. (2009) and + 46 percent based on Lepeule et al. (2012). d See Table 5

- 19 in Chapter 5 for detailed information on confidence intervals related to ozone

- related morbidity incidence estimates

. T he PM 2.5 morbidi ty incidence estimates were generated using benefit

- per

- ton estimates and confidence intervals are not available

. 

### Table ES

- 8

. Summary of Total Control Costs (Known and Extrapolated) by Alternative

Level for 2025

- U.S., except California (billions of 2011$, 7% Discount Rate) a

Alternative Level Geographic Area Total Control Costs (Known and Extrapolated) 70 ppb East 3 .9 West

- Total $ 3 .9
65 ppb East 15 West 0.4 0 Total $15 60 ppb East 33 West 5 .8 Total $39

a All values are rounded to two significant figures. Extrapolated costs are based on the average

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### ES

- 16

Table ES

- 9

. Regional Breakdown of Monetized O zone - Specific Benefits Results for the

2025 S cenario (nationwide benefits of attaining each alternative standard everywhere in the U.S. except California)

– Full Attainment a
Region Proposed and Alterative Standards 70 ppb 65 ppb 60 ppb East b 99% 96% 92% California 0% 0% 0% Rest of West 1% 4% 7%

a Because we use benefit

- per

- ton estimates to calculate the PM 2.5 co

- benefits, a regional breakdown for the co

benefits is not available. Therefore, this table only reflects the ozone benefits. b Includes Texas and those states to the north and east. Several recent rules such as Tier 3 will have substantially reduced ozone concentrations by 2025 in the East, thus few additional controls woul d be needed to reach 70 ppb.



### T o understand possible additional costs and benefits of fully attaining in California in a post

- 2025 timeframe , we provide supplemental separate results for California in Table ES

- 8 10

. In addition, Tables 5

- 2 and 5

- 3 0 in Chapter 5 provide a breakdown of ozone

- only and PM 2.5 

### - only
benefits , as well as total benefits at 3 percent

. Relative to the primary cost and benefits estimates, the California cost estimates are between 5 and 20 percent and the benefits estimates

are between 8 and 15 percent of the national estimates. B ecause of the differences in the timing of achieving needed emissions reductions, incurring costs, and accruing benefits for California,
the supplemental separate costs and benefits estimates for post

- 2 025 should not be added to the primary estimates for 2025. For the post

- 2025 timeframe , Table ES

- 9 11 presents the numbers of premature deaths avoided for the alternative standard levels analyzed, as well as the other health
effects avoided. Table ES

- 12 p rovides information on the costs for California for post

- 2025, and
Table ES

- 13 provides a regional breakdown of benefits for post

- 2025.

The EPA presents separate and supplemental costs and benefits results for California because forcing attainment in an earlier year than would be required under the Clean Air Act would likely lead to an overstatement of costs because California might benefit from some existing federal or state progr ams that would be implemented between 2025 and the ultimate attainment years; because additional new technologies may become available between 2025 and the attainment years; and because the cost of existing technologies might fall over time. As such,

we u se the best available data to estimate costs and benefits for California in a post

- 2025 timeframe, but because of data limitations and additional uncertainty associated with not projecting emissions and air quality beyond 2025, we recognize that the estima tes of costs and Formatted: Font: (Default) Times New Roman Formatted: Font: (Default) Times New Roman

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- 17

benefits for California in a post

- 2025 timeframe are likely to be relatively more uncertain than
the national attainment estimates for 2025.

Table ES

- 8 10

. Total Annual Costs a and Benefits b a 

### of Control Strateg ies Applied in

for Californi a, post

- 2025 (billions of 2011$, 7% Discount Rate) b
Proposed Alternative Standard Levels Alternative Standard Level 70 ppb 65 ppb 60 ppb Total Costs (7%) $0.80 $1 .6 $ 2.2 Total Health Benefits (7%) c $ 1.1 to $2 $ 2.2 to $4.1 $3 .2 to $5.9 Net Benefits (7%) $ 0.3 to $1.2 $ 0.60 to $2.5 $1 to $3.7

Proposed Alternative Standard Levels Alternative Standard Level 70 ppb 65 ppb 60 ppb Total Costs (7%) $0.80 $1.6 $2.2 Health Benefits (3%) c $1.1 to $2 $2.3 to $4.2 $3.4 to $6.2 Health Benefits (7%) c $1.1 to $2 $2.2 to $4.1 $3.2 to $5.9 Net Benefits (3%) $0.3 to $1.2 $0.70 to $2.6 $1.2 to $4 Net Benefits (7%) $0.3 to $1.2 $0.60 to $2.5 $1 to $3.7

a Engineering costs reflect 7% discount rate. We do not have a comprehensive data set to be able to calculate engineering costs at a 3% discount rate. b a Benefits are nationwide benefits of attainment in California. b EPA believes that providing comparison s of social costs and social benefits at 3 and 7 percent is appropriate. Estimating multiple years of costs and benefits is not possible for this RIA due to data and resource limitations. As a result, we provide a snapshot of costs and benefits in 2025, u sing the best available information to approximate social costs and social benefits recognizing uncertainties and limitations in those estimates.

c c The benefits range reflects the LOW and UPPER core estimates of short

- term ozone and long

- term PM mortality.



### Table ES

- 11 9

. Summary of Total Number of Annual Ozone and PM

- Related

Premature Mortalities and Premature Morbidity: Post

- 2025 a

Proposed Alternative Standard Levels (95th percentile confidence intervals) b Alternative Standard Level (95th percentile confidence intervals) 70 ppb 65 ppb 60 ppb Short

- term exposure

- related premature deaths avoided (all ages) (Ozone

– 2 studies) 65 to 110 (31 to 97) (57 to 160) 140 to 230 (68 to 210) (120 to 340) 210 to 350 ( 100 to 320) (190 to 510) Long

- term exposure

- related premature deaths avoided (age 30+) (PM

– 2 studies) O 3 : 260 (88 to 430) PM 2.5 : 45 to 100 c O 3 : 560 (190 to 930) PM 2.5 : 89 to 200 c O 3 : 840 (290 to 1,400) PM 2.5 : 120 to 280 c Other health effects avoided d Non

- fatal heart attacks (age 18

- 99) (5 studies) PM 6 to 54 11 to 110 16 to 140 Respiratory hospital admissions (age 0

- 99) O3, PM 130 280 430 Formatted Table

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### ES

- 18 Proposed Alternative Standard Levels (95th percentile confidence intervals) b Alternative Standard Level (95th percentile confidence intervals) 70 ppb 65 ppb 60 ppb Cardiovascular hospital admissions (age 18

- 99) PM 16 32 45 Asthma emergency department visits (age 0

- 18) O3, PM 340 730 1,100 Acute bronchitis (age 8

- 12) PM 67 130 180 Asthma exacerbation (age 6

- 18) O3, PM 99,000 210,000 320,000 Lost work days (age 18

- 65) PM 5,500 11,000 15,000 Minor restricted activity days (age 18

- 65) O3, PM 320,000 690,000 1,000,000 Upper & lower respiratory symptoms (children) PM 2,100 4,100 5,600 School loss days O3 110,000 230,000 350,000

a Nationwide benefits of attainment in California. b We present a confidence interval in parentheses for each study on short

- term or long

- term ozone

- related mortality.

c These estimates were generated using benefit

- per

- ton estimates and confidence intervals are not available. In general, the 95th percentile confidence interval for the health impact function alone ranges from + 30 percent for mortality incidence based on Krewski et al. (2009) and + 46 percent based on Lepeule et al. (2012). d See Table 5

- 26 in Chapter 5 for detailed information on confidence intervals related to ozone

- related morbidity incidence estimates. The PM2.5 morbidity incidence estimates were gene rated using benefit

- per

- ton estimates and confidence intervals are not available.



### Table ES

- 1 2

. Summary of Total Control Costs (Known and Extrapolated) by Alternative

Level for post

- 2025

- California ( b illions of 2011$, 7% Discount Rate) a

Alternative Level Geographic Area Total Control Costs (Known and Extrapolated) 70 ppb California $0.80 65 ppb California $1.6 60 ppb California $2.2

a All values are rounded to two significant figures. Extrapolated costs are based on the average

- cost methodology.



### Table ES

- 1 3

. Regional Breakdown of Monetized O zone - Specific Benefits Results for the

post

- 2025 S cenario (nationwide benefits of attaining each alternative standard

just in California)

– Full Attainment a
Region Proposed and Alterative Standards

70 ppb 65 ppb 60 ppb East 0% 0% 0% California 93% 94% 94% Rest of West 6% 6% 6%

a Because we use benefit

- per

- ton estimates to calculate the PM 2.5 co

- benefits, a regional breakdown for the co

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- 19

Despite uncertainties inherent in any complex, quantitative analysis, the overall underlying analytical methods used in this RIA have been peer

- reviewed . For a detailed discussion on uncertainty associated with developing illustrative control strategies to attain the alternative standard levels, see Chapter 4, Section 4.4. For a description of the key assumptions and uncertainties related to the modeling of ozone benefits, see Chapter 5, Section 5.7.3, and for an additional qualitative discussion of sources of uncertainty associated with both the modeling of

ozone

- related benefits and PM 2.5 

### - related co

- benefits, see Appendix 5A. For a discussion of the limitations and uncertainties in the engineering cost analyses, see Chapter 7, Sectio n 7.7. For a discussion about generally framing uncertainty, see Chapter 8, Section 8.3.

ES.3 References
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Fann N, Lamson A, Wesson K, Risl ey D, Anenberg SC, Hubbell BJ. 2012a. “Estimating the National Public Health Burden Associated with Exposure to Ambient PM 2.5 and ozone. Risk Analysis,” Risk Analysis 32(1): 81

- 95.
Levy JI, Baxter LK, Schwartz J. 2009. “ Uncertainty and variability in healt h

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Pye, J.M. 1988. Impact of ozone on the growth and yield of trees: A review. Journal of Environmental Quality, 17, 347

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U.S. Environmental Protection Agency (U.S. EPA). 2013. Integrated Science Assessment of Ozone and Related Photochemical Oxidants (Final Report). EPA

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. U.S. Environmental Protection Agency (U.S. EPA). 2014b. Proposed Carbon Pollution Guidelines for Existing Power Plants and Emission Standards for Modified and Reconstructed Power Plants. Available at http://www2.epa.gov/sites/production/files/2014

- 06/documents/20140602ria

- clean

- power

- plan.pdf
U.S. Environmental Protection Agency. 2014 c . Policy Assessment for the Review of the Ozone NAAQS, Final Report. August. Available on the Internet at http://www.epa.gov/ttn/naaqs/standards/ozone/data/20140829pa.pdf

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