6-1

CHAPTER 6: IMPACTS ON PUBLIC WELFARE OF ATTAINMENT STRATEGIES 

TO MEET PRIMARY AND SECONDARY OZONE NAAQS 

Overview

This chapter provides a discussion of the welfare-related benefits of meeting alternative 

primary and secondary ozone standards. Welfare benefits of reductions in ambient ozone 

include increased growth and/or biomass production in sensitive plant species, including forest 

trees, increased crop yields, reductions in visible foliar injury, increased plant vigor (e.g. 

decreased susceptibility to harsh weather, disease, insect pest infestation, and competition), and 

changes in ecosystems and associated ecosystem services. We provide a limited quantitative 

analysis for effects associated with changes in yields of commercial forests and agriculture, and 

associated changes in carbon sequestration and storage. 

The EPA is proposing to revise the level of the secondary standard to within the range 

proposed for the primary standard of 65 parts per billion (ppb) to 70 ppb to provide increased 

protection against vegetation-related effects on public welfare. 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 protection 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 indicate 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. The quantitative analysis in this chapter assesses the welfare 

benefits of strategies to attain ozone standard levels of 65 to 70 ppb. 

In addition to the direct welfare benefits of decreased levels of ambient ozone, the 

emissions reduction strategies used to demonstrate attainment with alternative ozone standards 

may result in additional benefits associated with reductions in nitrogen deposition and reductions 

in ambient concentrations of PM2.5 and its components. These additional benefits include 

reductions in nutrient enrichment and acidification impacts on sensitive aquatic and terrestrial 

ecosystems and improvements in visibility in state and national parks, wilderness areas, and in 

the areas where people live and work. We are not able to quantify or monetize these benefits in 

this RIA.
6-2

6.1 Welfare Benefits of Strategies to Attain Primary and Secondary Ozone Standards

The 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 ecosystem 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 structures or by soiling of surfaces (Section 302(h) 

(42 U.S.C. § 7602(h)). For welfare effects associated with changes to ecosystem functions, we 

use the concept of ecosystem services as a useful framework for analyzing the impact of 

ecosystem changes on public welfare. Ecosystem services can be generally defined as the 

benefits that individuals and organizations obtain from ecosystems. The EPA has defined 

ecological goods and services as the “outputs of ecological functions or processes that directly or 

indirectly contribute to social welfare or have the potential to do so in the future. Some outputs 

may be bought and sold, but most are not marketed” (U.S. EPA, 2006). Changes in these 

services can affect human well-being by affecting security, health, social relationships, and 

access to basic material goods (MEA, 2005).

This RIA employs reductions in nitrogen oxides (NOx) and volatile organic compound 

(VOC) emissions to demonstrate attainment with alternative levels of the NAAQS. Reductions 

in these emissions will result in changes in ambient concentrations of ozone, as well as changes 

in ambient concentrations of NOx, PM2.5 and its components, and deposition of nitrogen. It is

appropriate and reasonable to include all the benefits associated with these emissions reductions

to provide a comprehensive understanding of the likely public welfare impacts of attaining

alternative standards. Table 6-1 shows the welfare effects associated with emissions of NOx and 

VOC. The following subsections discuss the direct benefits of reducing ambient ozone 

concentrations and the additional welfare benefits associated with reduced emissions of NOx and 

VOC.
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Table 6-1. Welfare Effects of NOx and VOC Emissions

Pollutant

Atmospheric Effects Atmospheric and 

Deposition Effects Deposition Effects

Vegetation 

Injury (Ozone)

Visibility 

Impairment

Materials 

Damage

Climate

Ecosystem 

Effects—

(Organics)

Acidification 

(freshwater)

Nitrogen 

Enrichment

NOx      

VOCs    

6.2 Welfare Benefits of Reducing Ozone

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

When ozone is present in ambient air, it can enter the leaves of plants, where it can cause 

significant cellular damage. Like carbon dioxide and other gaseous substances, ozone enters 

plant tissues primarily through the stomata in leaves in a process called “uptake” (Winner and 

Atkinson, 1986). Once sufficient levels of ozone (a highly reactive substance), or its reaction 

products, reaches the interior of plant cells, it can inhibit or damage essential cellular 

components and functions, including enzyme activities, lipids, and cellular membranes, 

disrupting the plant’s osmotic (i.e., water) balance and energy utilization patterns (U.S. EPA, 

2013; Tingey and Taylor, 1982). With fewer resources available, the plant reallocates existing 

resources away from root growth and storage, above ground growth or yield, and reproductive 

processes, and toward leaf repair and maintenance, leading to reduced growth and/or 

reproduction. Studies have shown that plants stressed in these ways may exhibit a general loss 

of vigor, which can lead to secondary impacts that modify plants' responses to other 

environmental factors. Specifically, plants may become more sensitive to other air pollutants, or 
6-4

more susceptible to disease, pest infestation, harsh weather (e.g., drought, frost) and other 

environmental stresses, which can all produce a loss in plant vigor in ozone-sensitive species that 

over time may lead to premature plant death. Furthermore, there is evidence that ozone can 

interfere with the formation of mycorrhiza, essential symbiotic fungi associated with the roots of 

most terrestrial plants, by reducing the amount of carbon available for transfer from the host to 

the symbiont (U.S. EPA, 2013).

This ozone damage may or may not be accompanied by visible injury on leaves, and 

likewise, visible foliar injury may or may not be a symptom of the other types of plant damage 

described above. Foliar injury is usually the first visible sign of injury to plants from ozone 

exposure and indicates impaired physiological processes in the leaves (Grulke, 2003). When 

visible injury is present, it is commonly manifested as chlorotic or necrotic spots, and/or 

increased leaf senescence (accelerated leaf aging). Visible foliar injury reduces the aesthetic 

value of ornamental vegetation and trees in urban landscapes and negatively affects scenic vistas 

in protected natural areas. 

Ozone can produce both acute and chronic injury in sensitive species depending on the 

concentration level and the duration of the exposure. Ozone effects also tend to accumulate over 

the growing season of the plant, so that even lower concentrations experienced for a longer 

duration have the potential to create chronic stress on sensitive vegetation. Not all plants, 

however, are equally sensitive to ozone. Much of the variation in sensitivity between individual 

plants or whole species is related to the plant’s ability to regulate the extent of gas exchange via 

leaf stomata (e.g., avoidance of ozone uptake through closure of stomata) and the relative ability 

of species to detoxify ozone-generated reactive oxygen free radicals (U.S. EPA, 2013; Winner, 

1994). After injuries have occurred, plants may be capable of repairing the damage to a limited 

extent (U.S. EPA, 2013). Because of the differing sensitivities among plants to ozone, ozone 

pollution can also exert a selective pressure that leads to changes in plant community

composition. Given the range of plant sensitivities and the fact that numerous other 

environmental factors modify plant uptake and response to ozone, it is not possible to identify

threshold values above which ozone is consistently toxic for all plants. 
6-5

Because plants are at the base of the food web in many ecosystems, changes to the plant 

community can affect associated organisms and ecosystems (including the suitability of habitats 

that support threatened or endangered species and below ground organisms living in the root 

zone). Ozone impacts at the community and ecosystem level vary widely depending upon 

numerous factors, including concentration and temporal variation of tropospheric ozone, species 

composition, soil properties and climatic factors (U.S. EPA, 2013). In most instances, responses 

to chronic or recurrent exposure in forested ecosystems are subtle and not observable for many 

years. These injuries can cause stand-level forest decline in sensitive ecosystems (U.S. EPA, 

2013, McBride et al., 1985; Miller et al., 1982). It is not yet possible to predict ecosystem 

responses to ozone with certainty; however, considerable knowledge of potential ecosystem 

responses is available through long-term observations in highly damaged forests in the U.S. (U.S 

EPA, 2013). Biomass loss due to ozone exposure affects climate regulation by ecosystems by

reducing carbon sequestration. More carbon stays in the atmosphere because carbon uptake by

forests is reduced. The studies cited in the Ozone ISA demonstrate a consistent pattern of 

reduced carbon uptake because of ozone damage, with some of the largest reductions projected 

over North America (U.S. EPA, 2013). 

Ozone also directly contributes to climate change because tropospheric ozone traps heat, 

leading to increased surface temperatures. Projections of radiative forcing due to changing 

ozone concentrations over the 21st century show wide variation, due in large part to the 

uncertainty of future emissions of source gases (U.S. EPA 2014). However, reduction of 

tropospheric ozone concentrations could provide an important means to slow climate change in 

addition to the added benefit of improving surface air quality (U.S. EPA, 2014).

While it is clear that increases in tropospheric ozone lead to warming, the precursors of 

ozone also have competing effects on methane, complicating emissions reduction strategies. A 

decrease in carbon monoxide or VOC emissions would shorten the lifetime of methane, leading 

to an overall cooling effect. A decrease in NOX emissions could lengthen the methane lifetime in 

certain regions, leading to warming (U.S. EPA, 2014). Additionally, some strategies to reduce 

ozone precursor emissions could also lead to the reduced formation of aerosols (e.g., nitrates and 

sulfates) that currently have a cooling effect.
6-6

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 standards. 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 proposed 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 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 production, 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 (WREA) (U.S. EPA, 2014).

6.3 Additional Welfare Benefits of Strategies to Meet the Ozone NAAQS

Reductions in emissions of NOx and VOC are associated with additional welfare benefits, 

including reductions in nutrient enrichment and acidification impacts on sensitive aquatic and 

terrestrial ecosystems and improvements in visibility in state and national parks, wilderness 

areas, and in the areas where people live and work. 

Excess nitrogen deposition can lead to eutrophication of estuarine waters, which is 

associated with a range of adverse ecological effects. These include low dissolved oxygen 

(DO), harmful algal blooms (HABs), loss of submerged aquatic vegetation (SAV), and low water 

clarity. Low DO disrupts aquatic habitats, causing stress to fish and shellfish, which, in the 

short-term, can lead to episodic fish kills and, in the long-term, can damage overall growth in 

fish and shellfish populations. HAB are often toxic to fish and shellfish, lead to fish kills and 

aesthetic impairments of estuaries, and can in some instances be harmful to human health. SAV 

provides critical habitat for many aquatic species in estuaries and, in some instances, can also 

protect shorelines by reducing wave strength. Low water clarity is in part the result of 

accumulations of both algae and sediments in estuarine waters. In addition to contributing to 
6-7

declines in SAV, high levels of turbidity also degrade the aesthetic qualities of the estuarine 

environment.

Nutrient enrichment from nitrogen deposition to terrestrial ecosystems is causally linked 

to alteration of species richness, species composition, and biodiversity (U.S. EPA, 2008b). 

Nitrogen enrichment occurs over a long time period; as a result, it may take as much as 50 years or 

more to see changes in ecosystem conditions, indicators, and services. 

Terrestrial acidification resulting from deposition of nitrogen can result in declines in

sensitive tree species, such as red spruce (Picea rubens) and sugar maple (Acer saccharum), and 

can also impact other plant communities including shrubs and lichen (U.S. EPA, 2008b).

Biological effects of acidification in terrestrial ecosystems are generally linked to aluminum

toxicity and decreased ability of plant roots to take up base cations (U.S. EPA, 2008b).

Terrestrial acidification affects several important ecosystem services, including declines in 

habitat for threatened and endangered species, declines in forest aesthetics, declines in forest

productivity, and increases in forest soil erosion and reductions in water retention. 

Aquatic acidification resulting from deposition of nitrogen can result in effects on health,

vigor, and reproductive success for aquatic species; and effects on biodiversity. Deposition of 

nitrogen results in decreases in the acid neutralizing capacity and increases in inorganic aluminum

concentration, which contribute to declines in zooplankton, macro invertebrates, and fish species

richness in aquatic ecosystems (U.S. EPA, 2008b).

Reductions in NOx emissions will improve visibility in parks and wilderness areas and in 

places where people live and work because of their impact on light extinction (U.S. EPA, 2009).

Good visibility increases quality of life where individuals live and work, and where they travel

for recreational activities, including sites of unique public value, such as the Great Smoky

Mountains National Park (U. S. EPA, 2009). Particulate nitrate is an important contributor to

light extinction in California and the upper Midwestern U.S., particularly during winter (U.S.

EPA, 2009). While EPA typically estimates the visibility benefits associated with reductions in NOx 

(U.S. EPA, 2008a), we have not done so here because we do not have estimates of the changes in 

particulate nitrate needed to calculate changes in light extinction and the resulting changes in 

economic benefits.
6-8

Strategies implemented by state and local governments to reduce emissions of ozone 

precursors may also impact emissions of CO2 or other long-lived climate gases. Our ability to 

quantify the climate effects of the proposed standard levels is limited due to lack of available 

information on the energy and associated climate gas implications of control technologies 

assumed in the illustrative control strategy alternatives, remaining uncertainties regarding the 

impact of ozone precursors on climate change, and lack of available information on the cocontrolled greenhouse gas (GHG) emission reductions. As a result, we do not attempt to 

quantify the impacts of the illustrative attainment scenarios on GHG emissions and impacts.

6.4 Analysis of Commercial Agricultural and Forestry Related Benefits Using the 

Forest and Agricultural Sector Optimization Model – Greenhouse Gas Version 

(FASOMGHG)

To estimate the commercial timber effects of ozone induced biomass loss we used the 

FASOMGHG (Adams et al., 2005) model for the forest and agricultural sectors to calculate the 

market-based welfare benefits associated with the illustrative attainment strategies for the three 

alternative ozone standard levels of 70, 65, and 60 ppb incremental to attainment of the current 

standard level of 75 ppb. This section provides a brief summary of the analytical approach and 

results of the analysis. More details of the FASOMGHG modeling conducted for this RIA are 

provided in Appendix 6A, while additional details on the overall FASOMGHG methodology are 

provided in Appendix 6B of the WREA (U.S. EPA, 2014).

6.4.1 Summary of the Analytical Approach

We used the ozone exposure-response functions evaluated in the ISA (U.S. EPA, 2013) for 

tree seedlings to calculate relative yield loss (RYL), which is equivalent to relative biomass loss, 

for trees over their entire life span. The RYL for species were aggregated into average RYL for 

FASOMGHG forest types, based on mapping tree species to forest types using the Atlas of 

United States Trees (Little, 1971, 1976, 1977, 1978). 

We used the NCLAN ozone exposure-response functions evaluated in the ISA to generate 

RYL for commercial agricultural crops. For those crops that do not have E-R functions, we 
6-9

assign them RYLs for each scenario based on the crop proxy mapping shown in Table 6A-2 of 

Appendix 6A.1 The RYL for each crop are aggregated to the regional level by computing a 

weighted average RYL with weights determined by a county’s share of production for the crop. 

Additional details of the calculations of RYL are provided in Appendix 6A.

Yield gains for both forest species and crops are calculated as the difference in RYL

between the 75 ppb standard baseline and the attainment scenarios for 70, 65, and 60 ppb 

alternative standard levels. The FASOMGHG model requires estimates of yields over a time 

horizon from 2010 to 2040. As such, we needed to specify yield gains over this range of years. 

Yield gains are calculated for three periods, 2010 to 2025, 2025-2038, and post-2038. The pre2025 period has no changes in yields. The 2025-2038 period represents the effects on the W126 

index of attainment of the alternative standards across the U.S. with the exception of California. 

The post-2038 period includes the effects on the W126 index of attaining everywhere across the 

U.S. including California. There is clearly uncertainty in the path of the yield changes 

introduced by uncertainties about the specific time pattern of emissions reductions that will be 

applied in California to attain alterative standards.

Changes in yield are associated with changes in consumer and producer/farmer surplus. 

Consumer surplus is the difference between what a consumer would be willing to pay for a 

product and the price they have to pay for the product. Producer surplus refers to the benefit, or 

profit, a producer receives from providing a good or service at a market price when they would 

have been willing to sell that good or service at a lower price. In general, increases in yields will 

cause crop and timber prices to fall. These reductions in prices will have different impacts on 

consumer and producer surplus. Overall effects on producer and consumer surplus depend on 

the (1) ability of producers/farmers to substitute other crops that are less ozone sensitive, and (2) 

responsiveness of demand and supply. The FASOMGHG model estimates changes in consumer 

and producer surplus and net welfare (sum of consumer and producer surplus). The 

FASOMGHG model also provides estimates of the changes in carbon sequestration for the 

commercial forestry and agricultural sectors.

 

1

For oranges, rice, and tomatoes, which have ozone E-R functions that are not W126-based (they are defined based 

on alternative measures of ozone concentrations), we directly used the median RYG values under the “13 ppm-hrs” 

ozone concentration reported in Table G-7 of Lehrer et al. (2007). 
6-10

The model calculates market equilibria under each of the alternative standard scenarios 

reflecting different forest and agricultural yields resulting from different ozone exposures. By

comparing the market equilibria under different scenarios, we can calculate the welfare and 

carbon sequestration impacts of alternative ozone standards for the U.S. agricultural and forest 

sector. 

6.4.2 Summary of FASOMGHG Results

Tables 6-2 and 6-4 show the estimated changes in consumer and producer surplus 

associated with attainment of the alternative ozone standards compared to attaining the current 

standard for the forestry and agricultural sectors, respectively. Tables 6-3 and 6-5 show the 

percent change in consumer and producer surplus associated with attainment of the alternative 

ozone standards compared to attaining the current standard for the forestry and agricultural 

sectors, respectively. Consumer and producer welfare are affected more in the forestry sector 

than the agricultural sector. In general, consumer welfare increases in both the forestry and 

agricultural sectors because higher yields lead to lower prices. Because the quantity demanded 

for most forestry and agricultural commodities is not highly responsive to changes in price, 

producer surplus often declines when lower prices reduce producer profits more than can be 

offset by higher yields. In other words, consumers do not increase their demand in response to 

the falling prices enough to offset the producer’s loss of revenue. The increase in consumer 

welfare is not as large as the loss of producer welfare resulting in net welfare losses in the 

forestry sector nationally.

Table 6-2. Change in Consumer and Producer Surplus in the Forestry Sector from 

Attaining Alternative Ozone Standard Levels Compared to Attaining the 

Current Ozone Standard (Million 2011$)

Alternative Standard Level 2010 2015 2020 2025 2030 2035 2040

Consumer 

Surplus

Change with Respect to Existing Standard

70 ppb 3 24,592 -8 111 136 225 61

65 ppb 11 24,596 8 305 337 552 162

60 ppb 30 24,742 136 719 533 1,094 311

Producer 

Surplus

Change with Respect to Existing Standard

70 ppb 1,203 -22,160 1,768 703 -1,167 523 -52,496

65 ppb 211 -24,091 -480 1,464 -3,044 -39,691 -10,246

60 ppb -233 -23,711 -1,731 1,455 -1,963 -39,291 -8,082
6-11

Table 6-3. Percent Change in Consumer and Producer Surplus in the Forestry Sector from 

Attaining Alternative Ozone Standard Levels Compared to Attaining the 

Current Ozone Standard

Alternative Standard Level 2010 2015 2020 2025 2030 2035 2040

Consumer 

Surplus

Percent Change with Respect to Existing Standard

70 ppb 0.00% 3.10% 0.00% 0.01% 0.02% 0.03% 0.01%

65 ppb 0.00% 3.10% 0.00% 0.04% 0.04% 0.06% 0.02%

60 ppb 0.00% 3.12% 0.02% 0.09% 0.06% 0.12% 0.03%

Producer 

Surplus

Percent Change with Respect to Existing Standard

70 ppb 0.15% -2.28% 0.18% 0.07% -0.12% 0.05% -5.04%

65 ppb 0.03% -2.48% -0.05% 0.14% -0.32% -3.88% -0.98%

60 ppb -0.03% -2.44% -0.18% 0.14% -0.20% -3.84% -0.78%

Table 6-4. Change in Consumer and Producer Surplus in the Agricultural Sector from 

Attaining Alternative Ozone Standard Levels Compared to Attaining the 

Current Ozone Standard (Million 2011$)

Product

Alternative 

Standard 

Level 2010 2015 2020 2025 2030 2035 2040

Consumer 

Surplus

Change with Respect to Existing Standard

70 ppb 0 0 0 113 66 58 -10

65 ppb -1 1 4 262 148 289 24

60 ppb 0 47 9 462 100 408 66

Producer 

Surplus

Change with Respect to Existing Standard

70 ppb 1,202 2,454 1,796 609 -1,144 675 -52,504

65 ppb 216 530 -407 1,174 -2,933 -39,605 -10,211

60 ppb -176 1,015 -1,470 1,320 -1,492 -38,788 -8,119

Table 6-5. Percent Change in Consumer and Producer Surplus in the Agricultural Sector 

from Attaining Alternative Ozone Standard Levels Compared to Attaining the 

Current Ozone Standard

Product

Alternative 

Standard 

Level 2010 2015 2020 2025 2030 2035 2040

Consumer 

Surplus

Percent Change with Respect to Existing Standard

70 ppb 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00%

65 ppb 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00%

60 ppb 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00%

Producer 

Surplus

Percent Change with Respect to Existing Standard

70 ppb 0.17% 0.30% 0.22% 0.07% -0.14% 0.08% -5.78%
6-12

65 ppb 0.03% 0.06% -0.05% 0.14% -0.36% -4.53% -1.12%

60 ppb -0.02% 0.12% -0.18% 0.15% -0.18% -4.44% -0.89%

Since the forestry and agriculture sectors are interlinked and factors affecting one sector 

can lead to changes in the other, it is important to consider the overall effect of ozone changes in 

the context of producer and consumer welfare across both sectors. The impacts on consumer 

surplus are positive for both sectors, with benefits increasing with lower alternative standards. 

For producer surplus, however, impacts are negative for all alternative standards. Table 6-6 and 

6-8 present the annualized surplus (over the period 2010 to 2040) for both sectors using 3 and 7 

percent discount rates, while Table 6-7 and 6-9 present the percent change in surplus for both 

sectors using 3 and 7 percent discount rates.

Table 6-6. Annualized Changes in Consumer and Producer Surplus in Agriculture and 

Forestry from Attaining Alternative Ozone Standard Levels Compared to 

Attaining the Current Ozone Standard, 2010-2040, Million 2011$ (3% Discount 

Rate)

Alternative 

Standard Level Agriculture Forestry Total

Consumer surplus

Change with Respect to Existing Standard

70 ppb 28 4,552 4,580

65 ppb 86 4,592 4,678

60 ppb 132 4,744 4,877

Producer surplus

Change with Respect to Existing Standard

70 ppb -3,601 -4,534 -8,135

65 ppb -5,035 -4,524 -9,559

60 ppb -4,741 -4,684 -9,425

Total surplus

Change with Respect to Existing Standard

70 ppb -3,573 18 -3,555

65 ppb -4,949 68 -4,882

60 ppb -4,608 60 -4,548
6-13

Table 6-7. Annualized Percent Changes in Consumer and Producer Surplus in Agriculture 

and Forestry from Attaining Alternative Ozone Standard Levels Compared to 

Attaining the Current Ozone Standard, 2010-2040, (3% Discount Rate)

Alternative 

Standard Level Agriculture Forestry Total

Consumer surplus

Percent Change with Respect to Existing Standard

70 ppb 0.00% 0.57% 0.17%

65 ppb 0.00% 0.57% 0.17%

60 ppb 0.01% 0.59% 0.18%

Producer surplus

Percent Change with Respect to Existing Standard

70 ppb -0.44% -3.35% -0.85%

65 ppb -0.62% -3.34% -1.00%

60 ppb -0.58% -3.46% -0.99%

Total surplus

Percent Change with Respect to Existing Standard

70 ppb -0.13% 0.00% -1.10%

65 ppb -0.18% 0.01% -0.13%

60 ppb -0.17% 0.01% -0.12%

Table 6-8. Annualized Changes in Consumer and Producer Surplus in Agriculture and 

Forestry from Attaining Alternative Ozone Standard Levels Compared to 

Attaining the Current Ozone Standard, 2010-2040, Million 2011$ (7% Discount 

Rate)

Alternative 

Standard Level Agriculture Forestry Total

Change with Respect to Existing Standard

Consumer surplus 70 ppb 21 5,570 5,592

65 ppb 61 5,599 5,660

60 ppb 100 5,721 5,821

Producer surplus

Change with Respect to Existing Standard

70 ppb -945 -5,561 -6,506

65 ppb -2,719 -5,555 -8,273

60 ppb -2,635 -5,694 -8,328

Total surplus

Change with Respect to Existing Standard

70 ppb -923 9 -914

65 ppb -2,658 45 -2,613

60 ppb -2,535 27 -2,508

Table 6-9. Annualized Percent Changes in Consumer and Producer Surplus in Agriculture 

and Forestry from Attaining Alternative Ozone Standard Levels Compared to 

Attaining the Current Ozone Standard, 2010-2040, (7% Discount Rate)

Alternative 

Standard Level Agriculture Forestry Total
6-14

Percent Change with Respect to Existing Standard

Consumer surplus 70 ppb 0.00% 0.71% 0.20%

65 ppb 0.00% 0.72% 0.21%

60 ppb 0.01% 0.73% 0.21%

Producer surplus

Percent Change with Respect to Existing Standard

70 ppb -0.12% -4.26% -0.70%

65 ppb -0.34% -4.25% -0.89%

60 ppb -0.33% -4.36% -0.89%

Total surplus

Percent Change with Respect to Existing Standard

70 ppb -0.03% 0.00% -0.02%

65 ppb -0.10% 0.00% -0.07%

60 ppb -0.09% 0.00% -0.07%

The impacts of the simulations of meeting the existing and alternative ozone standards on 

carbon sequestration potential in U.S. forest and agricultural sectors are presented in Table 6-10, 

in millions of metric tons of carbon dioxide equivalence, and the percent change in carbon 

sequestration potential is presented in Table 6-11. As shown in the table, much greater 

sequestration changes are projected in the forest sector than in the agricultural sector. The 

baseline stock of carbon storage decreases over time for agriculture because the agriculture 

sector GHG emissions sources are released every year and soil carbon sequestration stabilizes 

over the 30-year period. There are only small increases in net carbon sequestration compared to 

the existing standard for each of the alternative scenarios modeled.

While we did not quantify the effects in this RIA, increases in growth for trees in urban 

settings that results from reduced ozone concentrations can have additional benefits from 

removal of air pollution. The WREA (U.S. EPA, 2014) provides a case study of the potential 

impacts of ozone reductions on pollution removal in several eastern U.S. urban areas using the iTree model. See appendix 6D of the WREA (U.S. EPA, 2014) for details and references for the 

i-Tree model.
6-15

Table 6-10. Increase in Carbon Sequestration from Attaining Alternative Ozone 

Standard Levels Compared to Attaining the Current Ozone Standard, 

MMtCO2e

Alternative Standard Level 2010 2020 2030 2040 2010-2040*

Agriculture

Change with Respect to Existing Standard

70 ppb 0 1 3 1 24

65 ppb 0 2 6 4 62

60 ppb 1 4 11 11 132

Forestry

Change with Respect to Existing Standard

70 ppb -1 -51 100 259 1,537

65 ppb -2 -53 323 774 5,207

60 ppb -12 -94 465 1,189 7,739

Table 6-11. Percent Change in Carbon Sequestration from Attaining Alternative Ozone 

Standard Levels Compared to Attaining the Current Ozone Standard

Alternative Standard Level 2010 2020 2030 2040 2010-2040*

Agriculture

Percent Change with Respect to Existing Standard

70 ppb 0.00% 0.00% 0.03% 0.01% 0.01%

65 ppb 0.00% 0.01% 0.05% 0.06% 0.02%

60 ppb 0.00% 0.03% 0.10% 0.13% 0.05%

Forestry

Percent Change with Respect to Existing Standard

70 ppb 0.00% -0.07% 0.13% 0.32% 0.10%

65 ppb 0.00% -0.07% 0.41% 0.95% 0.34%

60 ppb -0.02% -0.13% 0.60% 1.47% 0.50%

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