1

November 29, 2014

Mr. Thomas Webb

U.S. EPA, Region 9

Planning Office, Air Division, AIR–2

75 Hawthorne Street

San Francisco, CA 94105

Via email to webb.thomas@epa.gov

Re: Proposed California Regional Haze State Implementation Plan and Interstate 

Transport Plan

Dear Mr. Webb,

National Parks Conservation Association respectfully submits the following comments regarding 

California’s proposed Regional Haze State Implementation Plan Periodic Progress Report 

(“Progress Report”). The Progress Report represents an important opportunity for the State to 

take stock of whether the Regional Haze State Implementation Plan (“SIP”) is on track to meet 

the reasonable progress goals at Class I areas in California and other states impacted by visibility 

impairing pollution from California. Fortunately, most of the state’s 29 Class I national park and 

wildernesses have seen improvements in visibility; however, to restore natural air quality at the 

region’s Class I areas as mandated by Clean Air Act, additional pollutant reduction is necessary.

As explained below, to ensure that the reasonable progress goals are achieved, visibility 

improvements thus far are maintained, and the legal requirements for a progress report are 

satisfied, we ask EPA to include additional information and analysis now and in preparation for 

the 2018 SIP revision. In particular, we request EPA include:

 Emissions inventories that distinguish between reductions enforceably required by the 

SIP and those that are the result of non-enforceable conditions; 

 Emissions inventories that include natural emissions, include ammonia, and projected 

increases in emissions from oil and gas development;

 Enforceable limits on emissions that are not currently constrained; and
2

 A clear, consistent approach to assessing impacts from fire, including the interrelated 

categories of prescribed fires and wildfires.

These revisions will not only ensure progress towards natural visibility conditions at our 

protected national parks and wilderness areas, but will also benefit public health and ecosystems 

by reducing emissions of damaging pollution. 

I. THE CLEAN AIR ACT’S REGIONAL HAZE PROGRAM 

a. Development of a Regional Haze SIP 

In the 19th century, Congress had the foresight to set aside national parks so as to preserve some 

of the nation’s most spectacular scenery. See, e.g., John Copeland Nagle, The Scenic Protections 

of the Clean Air Act, 87 N.D. L. Rev. 571, 576 (2011). With the nation’s rapid industrialization, 

however, these remarkable scenic views have become increasingly marred by air pollution. See 

id. at 573. Today, air pollution is “perhaps the greatest threat to national parks,” and pollution all 

too often degrades visibility in these iconic scenic areas. Id. 

To reduce this threat to the national parks and other treasured public lands, Congress amended 

the Clean Air Act in 1977 to set a “national goal” of preventing all visibility impairment caused 

by human activities in national parks, wilderness areas, and other “Class I” federal areas. 42 

U.S.C. § 7491(a)(1). Congress again amended the Clean Air Act in 1990 to further spur 

reductions of regional haze after it concluded that the U.S. Environmental Protection Agency 

(“EPA”) and the states had not made adequate progress toward reducing haze. Id. § 7492. The 

Act delegates implementation of the regional haze program to EPA. The Agency set a goal of 

achieving natural visibility conditions at every Class I area by 2064, and the Agency directed 

states to make incremental, reasonable progress toward that goal. 40 C.F.R. § 51.308(d)(1)(i)(B), 

(d)(1)(ii).

To achieve natural visibility conditions by 2064, the goal set forth in the Clean Air Act’s 

implementing regulations, 40 C.F.R. §51.308(d)(1)(i)(B), the states are directed to create 

regional haze SIPs, which are then submitted to EPA for its review and approval. See 42 U.S.C. 

§§ 7410(a), 7491(b)(2). EPA evaluates the SIP and either approves or disapproves it in whole or 

in part. Id. § 7410(k)(3). If EPA’s evaluation reveals that a SIP does not comply with the Clean 

Air Act, then EPA must promulgate a FIP that remedies the shortcomings. Id. § 7410(c)(1). 

Each state’s regional haze SIP must include emissions limits on sources of air pollution within 

the state as necessary to protect visibility at all impacted Class I areas, both inside and outside 

the state. See 42 U.S.C. § 7491(a)(4), (b)(2). The 2064 natural visibility goal is to be achieved

through two key elements in a SIP: The first is the requirement that a particular category of 

sources install the “Best Available Retrofit Controls (BART) and the second is the requirement 

for a long-term strategy to encompass a wholistic look including and beyond BART to identify 

measures needed to achieve reasonable progress at each Class I area impaired by a state’s 

emissions. Id. § 7491(b)(2)(A); 40 C.F.R. § 51.308(d)&(e). BART is required at eligible 
3

sources1that are reasonably anticipated to cause or contribute to visibility impairment at national 

parks, wilderness areas, wildlife refuges and other “Class I areas” where air quality should be 

pristine. 42 U.S.C. § 7491(b)(2)(A). BART is an essential component of the regional haze 

program as it compels emissions reductions from older, disproportionately polluting sources that 

often have escaped control under other Clean Air Act programs. See id. 

In addition to requiring BART, each state’s regional haze SIP must also set goals, expressed in 

deciviews,2for each Class I area located within the state that will ensure reasonable progress 

toward achieving natural visibility conditions by 2064 (the “reasonable progress goals”). See 42 

U.S.C. § 7491(b)(2); 40 C.F.R. § 51.308(d)(1). The reasonable progress goals must provide for 

improvement in visibility on the most impaired days and ensure no degradation in visibility on 

the least impaired days over the period of the implementation plan. 40 C.F.R. § 51.308(d)(1). 

These goals are set after considering the anticipated visibility reductions over the planning period 

of the SIP from anticipated BART controls and other federal or state programs, as well as 

controls imposed on non-BART sources as part of a state’s long-term strategy section of a 

regional haze SIP to help achieve reasonable progress. See, e.g., 76 Fed. Reg. at 58,623.

States set the level of additional reasonable progress controls based on “the costs of compliance, 

the time necessary for compliance, the energy and non-air quality environmental impacts of 

compliance, and the remaining useful life of any potentially affected source . . . .” 40 C.F.R. § 

51.308(d)(1)(i)(A); 42 U.S.C. § 7491(g)(1). With the emissions reductions anticipated from 

these cumulative controls in mind, the state establishes the reasonable progress goals for the 

period of the SIPthrough 2018 in this case. 

b. The Role of Five-Year Progress Reports

Every five years after the submittal of its original SIP, states must evaluate the progress they are 

making in implementing the control measures included in their haze SIPs and whether they are 

on track to meet the visibility goals for Class I areas. 40 C.F.R. § 51.309(g). As part of these 

five-year progress reports, each state must assess whether its existing implementation plan is 

adequate to achieve its established goals for visibility improvement and emissions reductions. 40 

C.F.R. § 51.308(h). To determine the adequacy of the haze plan, each state must include in its 

progress report the following elements: 

(1) A description of the status of implementation of all measures included in the 

implementation plan for achieving reasonable progress goals for mandatory Class 

I Federal areas both within and outside the State;

(2) A summary of the emissions reductions achieved throughout the State through 

implementation of the measures described in paragraph (d)(10)(i)(A) of this 

section;

 

1 A source is BART-eligible if it is a stationary source within one of 26 enumerated categories, was not in operation 

before August 7, 1962, but was in existence on August 7, 1977, and has the potential to emit 250 tons per year or 

more of any pollutant. 42 U.S.C. § 7491(b)(2)(A), (g)(7). 

2 EPA uses the deciview as the principal metric for measuring visibility impairment. The deciview scale “expresses 

uniform changes in haziness in terms of common increments across the entire range of visibility conditions, from 

pristine to extremely hazy conditions.” 64 Fed. Reg. 35,714, 35,727 (July 1, 1999).
4

(3) For each mandatory Class I Federal area within the State, an assessment of the 

following: the current visibility conditions for the most impaired and least 

impaired days; the difference between current visibility conditions for the most 

impaired and least impaired days and baseline visibility conditions; the change in 

visibility impairment for the most impaired and least impaired days over the past 

5 years;

(4) An analysis tracking the change over the past 5 years in emissions of 

pollutants contributing to visibility impairment from all sources and activities 

within the State. Emissions changes should be identified by type of source or 

activity. The analysis must be based on the most recent updated emissions 

inventory, with estimates projected forward as necessary and appropriate, to 

account for emissions changes during the applicable 5-year period;

(5) An assessment of any significant changes in anthropogenic emissions within 

or outside the State that have occurred over the past 5 years that have limited or 

impeded progress in reducing pollutant emissions and improving visibility;

(6) An assessment of whether the current implementation plan elements and 

strategies are sufficient to enable the State, or other States with mandatory Federal 

Class I areas affected by emissions from the State, to meet all established 

reasonable progress goals; and

(7) A review of the State's visibility monitoring strategy and any modifications to 

the strategy as necessary.

40 C.F.R. § 51.308(g)(1)-(7). If, after considering the above elements, a state determines that its 

SIP is or may be inadequate to ensure reasonable progress, it must provide notification to the 

EPA, develop additional strategies to address the implementation plan deficiencies, collaborate 

with other States whose emissions may be impeding its progress, and revise the plan no later 

than one year from the date that the progress report was due. Id. § 51.308(h)(3)-(4).

II. CO-BENEFITS OF REDUCING HAZE POLLUTION

Addressing haze pollution impacting Class I areas has the critical co-benefit of protecting public 

health. Haze pollutants include nitrogen oxides, sulfur dioxide, particulate matter (“PM”), 

ammonia, and sulfuric acid, each of which poses a threat to public health. Nitrogen oxide is a 

precursor to ground level ozone, which is associated with respiratory diseases, asthma attacks, 

and decreased lung function. In addition, nitrogen oxide reacts with ammonia, moisture, and 

other compounds to form particulates that can cause and worsen respiratory diseases, aggravate 

heart disease, and lead to premature death. Similarly, sulfur dioxide increases asthma symptoms, 

leads to increased hospital visits, and can form particulates that aggravate respiratory and heart 

diseases and cause premature death. Particulate matter can penetrate deep into the lungs and 

cause a host of health problems, such as aggravated asthma, chronic bronchitis, and heart attacks.

Reducing these pollutants will have tremendous public health benefits, particularly in California, 

which has numerous areas in nonattainment with EPA’s National Ambient Air Quality Standards 

(“NAAQS”). EPA estimated that in 2015, full implementation of the Regional Haze Rule 

nationally will prevent 1,600 premature deaths, 2,200 non-fatal heart attacks, 960 hospital 
5

admissions, and over 1 million lost school and work days. Nationally, the Regional Haze Rule 

will result in health benefits valued at $8.4 to $9.8 billion annually. Investing in technologies that 

will reduce the pollutants that cause these asthma attacks, hospitalizations, heart attacks, 

emergency room visits and premature deaths is the right choice for California and the rest of the 

nation.

These same haze-causing emissions also harm terrestrial and aquatic plants and animals, soil 

health, and moving and stationary waterbodies – entire ecosystems – by contributing to acid rain, 

ozone formation, and nitrogen deposition. Nitrogen deposition, caused by wet and dry deposition 

of nitrates derived from NOx emissions, causes well known adverse impacts on ecological 

systems; in some places, saturation of the soil already exceeds the “critical load” the ecosystem 

can tolerate.3 Acid rain causes acidification of lakes and streams and can damage certain types of 

trees and soils. In addition, acid rain accelerates the decay of building materials and paints, 

including irreplaceable buildings, statues, and sculptures that are part of our nation's cultural 

heritage.”4 Further, haze-causing pollutants are precursors to ozone. Ground-level ozone 

formation impacts plants and ecosystems by: “interfering with the ability of sensitive plants to 

produce and store food, making them more susceptible to certain diseases, insects, other 

pollutants, competition and harsh weather; damaging the leaves of trees and other plants, 

negatively impacting the appearance of urban vegetation, as well as vegetation in national parks 

and recreation areas; and reducing forest growth and crop yields, potentially impacting species 

diversity in ecosystems.”5

III. CLASS I AREAS IN AND NEAR CALIFORNIA

California has more protected Class I areas than any other state. Emissions from California

impact visibility at all of its 29 Class I areas: 

1. Redwood National Park;

2. Marble Mountain Wilderness;

3. Lava Beds National Monument;

4. South Warner Wilderness;

5. Thousand Lakes Wilderness;

6. Lassen Volcanic National Park;

7. Caribou Wilderness;

8. Yolla Bolly Middle Eel Wilderness;

9. Point Reyes National Seashore;

10. Ventana Wilderness;

11. Pinnacles National Monument;

12. Desolation Wilderness;

13. Mokelumne Wilderness;

14. Emigrant Wilderness;

15. Hoover Wilderness;

 

3See, e.g., discussion of impacts on Rocky Mountain National Park. 

http://www.nature.nps.gov/air/permits/aris/romo/impacts.cfm.

4 http://www.epa.gov/acidrain/effects/index.html

5 http://www.epa.gov/glo/health.html
6

16. Yosemite National Park;

17. Ansel Adams Wilderness;

18. Kaiser Wilderness;

19. John Muir Wilderness;

20. Kings Canyon National Park;

21. Sequoia National Park;

22. Dome Lands Wilderness;

23. San Rafael Wilderness;

24. San Gabriel Wilderness;

25. Cucamonga Wilderness;

26. San Gorgonio Wilderness;

27. San Jacinto Wilderness;

28. Agua Tibia Wilderness; and,

29. Joshua Tree National Park.

In addition, emissions from California impact Class I areas in other states, such as Crater Lake 

National Park in Oregon and Grand Canyon National Park in Arizona. These Class I areas 

preserve the region’s inspiring landscapes, rare geologic formations, and diverse wildlife and 

vegetation. They also serve as living museums of our nation’s history. Visitors from across the 

nation and globe are drawn to these lands and their tourist dollars benefit state and local 

economies. 

IV. CALIFORNIA’S PROPOSED FIVE-YEAR PROGRESS REPORT MUST BE 

REVISED TO MEET 40 CFR 51.308(g) AND (h)

California submitted its first proposed haze plan to EPA in March 2009. As each state must 

submit a progress report five years after initial plan submittal, 40 C.F.R. § 51.308(g), California 

was required to submit its progress report by March 2014, and submitted the proposed version to 

EPA in June 2014. While in general the draft Progress Report offers an important accounting of 

how the haze SIP is being implemented, there are a number of areas in which it should be 

improved, including emissions inventories, enforceable limits, and assessment of impacts from 

fire. 

To clarify its regulatory requirements, in April 2013 EPA issued guidance regarding progress 

reports, entitled General Principles for the 5-Year Regional Haze Progress Reports for the Initial 

Regional Haze State Implementation Plans (Intended to Assist States and EPA Regional Offices 

in Development and Review of the Progress Reports) (“EPA April 2013 Guidance”). Among 

other elements, EPA’s April 2013 Guidance includes a checklist, mirroring the regulatory 

requirements, for evaluating progress report submittals.6 Each of the items noted above is 

discussed in detail below, in relation to the corresponding regulatory requirement.

 

6 p. 24-25. 
7

a. EPA Checklist for 40 C.F.R § 51.308(g)(2): Does the Report Include 

Estimated Reduction Estimates for these Measures?

40 C.F.R § 51.308(g)(2) requires each progress report to include a “summary of the emissions 

reductions achieved throughout the State through implementation of the measures described in 

paragraph (g)(1) of this section.” While Sections 2.4 and 2.5 of the Progress Report account for 

emissions reductions achieved in California, they do not summarize the emissions reductions 

achieved through implementation of the measures contained in the California haze SIP, as 

required by 40 C.F.R § 51.308(g)(2). That is, the Progress Report does not distinguish between 

emissions reductions achieved as a result of the haze SIP versus emissions reductions achieved 

as a result of other enforceable requirements or voluntary measures. 

The fundamental purpose of a progress report is to assess the efficacy of the haze SIP. It is 

difficult to render such an accounting if the State does not attempt to determine the emissions 

reductions required specifically by the haze SIP rather than by other programs. Accordingly, we 

urge EPA to require a revision of the draft Progress Report to quantify the emissions reductions 

achieved specifically as a result of the regional haze SIP. As EPA guidance notes, “progress 

reports should identify and estimate emissions reductions to date in visibility-impairing 

pollutants from the SIP measures.” (emphasis added).7

In particular, we encourage EPA to include emission reductions associated with the 

implementation of BART at the state’s only BART-regulated source, the Valero refinery in 

Benicia, California. EPA should also include a direct comparison of the emission projections 

relied on in the WRAP modeling underlying California’s reasonable progress goals versus the 

most recent emissions inventory, and to explain any discrepancies and projected changes to 

2018. 

b. EPA Checklist for 40 C.F.R § 51.308(g)(3): Does the report include the 

summaries of monitored visibility data as required by the Regional Haze 

Rule?

We encourage EPA to revise Section 3 of the Progress Report to include natural conditions and 

the uniform rate of progress (URP) milestones set by California’s haze SIP, both in graphical and 

tabular form, since those are the goals by which visibility progress is measured. The URP 

milestone indicates the progress that must be made if California’s Class I areas are to stay on 

track towards achieving natural visibility by 2064. In its initial SIP, California committed to 

including this comparison in the Progress Report.

8

 

7 EPA April 2013, General Principles for the 5-Year Regional Haze Progress Reports for the Initial Regional Haze 

State Implementation Plans (Intended to Assist States and EPA Regional Offices in Development and Review of the 

Progress Reports), p. 7. 

8 California committed to “compare the actual deciview calculations against progress towards reaching the RPGs 

and the uniform rate of progress...(CRHP, Section 9.3, page 9–2)” in its 5 year progress report. 76 FR 13961.
8

Our own comparisons of the progress thus far to the 2018 URP is shown below. 

2000-2004 

Worst Days 

Baseline (dv)

2018 Reasonable 

Progress Goal

(dv)

2018 Uniform 

Rate of Progress

(dv)

2008-2012 

Worst Days 

(dv)

Visibility 

Improvement to 

URP By 2012

TRIN 17.4 16.4 15.2 15.8 73%

LABE 15.1 14.4 13.4 13.7 82%

LAVO 14.1 13.3 12.6 15.6 -100%

BLIS 12.6 12.3 11.1 12.2 27%

HOOV 12.9 12.5 11.7 10.9 167%

YOSE 17.6 16.7 15.3 15.2 104%

KAIS 15.5 14.9 13.6 14.2 68%

SEQU 25.4 22.7 21.2 21.5 93%

DOME 19.4 18.1 16.6 17.5 68%

REDW 18.5 17.8 17.4 18.1 36%

PORE 22.8 21.3 21.2 21.2 100%

PINN 18.5 16.7 16 16.9 64%

RAFA 18.8 17.3 16.2 17.1 65%

SAGA 19.9 17.4 16.9 16.1 127%

SAGO 22.2 19.9 18.7 17.6 131%

AGTI 23.5 21.6 19.8 18.9 124%

JOSH 19.6 17.9 16.7 15.4 145%

As the table above shows, several of California’s Class I areas are currently meeting or 

exceeding the improvement required to attain the URP; however, some are not and would need 

to make additional progress in order to be on track. 

It would also be helpful for EPA to include the 5 year rolling averages of species extinction in 

graphical and tabular form for each Class I area. These depictions would more clearly illustrate 

the impacts associated with each pollutant species at the Class I areas and provide more context 

for changes in visibility thus far and the additional progress necessary to meet natural conditions. 

Finally, given the significant discussion of the impacts of out-of-jurisdiction sources on 

California’s Class I areas, we suggest that EPA clearly include estimates of emissions trends 

from relevant out of state sources as well.

c. EPA Checklist for 40 C.F.R § 51.308(g)(4): Does the report provide 

emissions trends across the entire inventory for a 5-year period as required 

by the Regional Haze Rule?

40 C.F.R § 51.308(g)(4) requires, among other things, an analysis covering the most current 5-

year period “based on the most recent updated emissions inventory, with estimates projected 

forward as necessary and appropriate.” Sections 2.4 and 2.5 of the Progress Report address this 

requirement. However, it appears that the inventory presented does not include natural sources. 

Given the significant – and increasing – role of wildfire in visibility impairment in California, we 
9

ask EPA to include emissions from natural sources in this emissions inventory, including 

projected future values. 

Similarly, it is not clear that California’s emission inventory includes several growing sources of 

anthropogenic emissions, including emissions related to increased oil and gas production (e.g. 

emissions from high-intensity production techniques such as fracking; projected increases in 

transportation of crude oil through California by rail; see discussion below).

Additionally, the Progress Report fails to discuss emissions of ammonia, a precursor to visibility 

impairing ammonium nitrate and ammonium sulfate. We ask EPA to include emissions 

inventory information for ammonia. 

d. EPA Checklist for 40 C.F.R § 51.308(g)(5): Does the Report include an 

explicit statement of whether there are anthropogenic emissions changes 

impeding progress?

40 C.F.R § 51.308(g)(5) obligates each progress report to include an “assessment of any 

significant changes in anthropogenic emissions within or outside the State that have occurred 

over the past 5 years that have limited or impeded progress in reducing pollutant emissions and 

improving visibility.” 

California appropriately discusses the impacts of wildfire, shipping emissions beyond 

California’s jurisdiction, and Asian dust. We have suggestions for EPA on each of these 

categories, as well as other anthropogenic changes not discussed by California. 

Fire Emissions

With regard to wildfire, we appreciate California’s discussion, and believe that it 

highlights the need for EPA to develop a nationally consistent methodology for 

accounting for fire with regard to regional haze. Although it is not entirely clear, we 

believe California’s Progress Report treats emissions from prescribed burns as

anthropogenic (and therefore controllable) emissions, and emissions from wildfires as 

natural (and therefore uncontrollable) emissions. This is an accurate, but conflicted, 

representation for several reasons. First, prescribed fires are largely intended to reduce 

the incidence of natural fires; they are inherently linked categories. Second, in addition to 

prescribed burns, there are many other human activities that influence the frequency and 

intensity with which natural fires occur (e.g. land management, campfire policies, general 

development, climate change, etc.). The statutory definition describes human made 

pollution as emissions resulting “directly or indirectly from human activities.” 42 U.S.C.

§ 7491. Thus, to the extent that natural fires are in part a result of human activity, they 

must be discussed as anthropogenic impacts to Class I areas. 

Additionally, it may not always be clear, from monitored data, whether impacts are due 

to wildfire versus other types of burning. Likewise, in the absence of a systemic 

approach, it is difficult to consistently assess the impact of fire not just in the most recent 

years, but also in the baseline (we note, for instance, that California’s discussion of 

wildfire impacts at LAVO does not appear to remove elevated wildfire impacts from 

2002 from the baseline). 
10

We ask EPA to develop and implement a clear, nationally applicable policy with regard 

to accounting for impacts from wildfire, prescribed fires, and other fire activity (e.g. 

agricultural burning), as appropriate considering its statutory responsibilities. 

Shipping and Asian Dust

We also appreciate California’s discussion of shipping emissions and Asian dust, 

including California’s efforts to reduce emissions from shipping that are within its 

jurisdiction. We encourage EPA to separately address emissions from federally regulated 

sources and to consult with other countries as appropriate to address transnational 

sources; we believe EPA has a statutory obligation to do so, considering its mandate to 

eliminate human made pollution in our protected public lands. 

Oil and Gas Emissions

We discuss above our concerns that some of the emission reductions relied on by 

California for progress seen thus far may not be enforceable moving forward, and thus 

may be temporary. In particular, we are concerned with the potential for increased 

emissions related to oil and gas development and production. 

We are concerned that some of California’s progress may be offset if significant 

emissions result from increased development of oil and gas resources, particularly 

through fracking and other high intensity production methods, both in California and off 

shore. Although projections of recoverable oil from the Monteray Shale formation in 

California were reduced recently,9the potential for increased development – and 

associated increases in NOx, VOCs, methane, and other gases – exists and must be 

regulated with haste.

Additionally, it is not clear that California’s emissions estimates include the impact of 

significantly increased importation of crude oil by rail. These imports have increased 

significantly since 2009, when they totaled 45,491 barrels Indeed, since 2012 – the last 

year for which California analyzes visibility data – crude by rail imports have increased 

from roughly 1 million barrels annually to more than 6 million barrels in 2013, 4 million 

barrels in 2014 through September, and over 1 million barrels imported by rail in 

December 2013 alone.10 New proposed projects indicate the potential for future 

increases. In addition to emissions resulting from the processing of this oil at California’s 

refineries, the increase in locomotive traffic associated with crude by rail has significant 

associated emissions, including of NOx, VOCs, and particulate matter. We ask EPA to 

take necessary actions to require that the emissions from these projects (along with any 

alternative methods of transportation of oil11) will not offset emission reductions and 

visibility progress achieved thus far. 

 

9 http://www.reuters.com/article/2014/05/21/eia-monterey-shale-idUSL1N0O713N20140521

10 Crude by rail import data available at http://energyalmanac.ca.gov/petroleum/statistics/. 

11 Crude by barge importation may be increasing as a result of opposition to crude by rail. See 

http://www.reuters.com/article/2014/10/23/us-california-bakken-barge-idUSKCN0IC17L20141023. This form of 

import likewise has emission implications for regional haze. 
11

Indirect Impacts of Climate Change

Emissions of greenhouse gases also impact regional haze, though indirectly, and the impact of 

climate change on regional haze must be taken into account in state planning to ensure that 

adequate progress towards visibility restoration be made in light of the exacerbating effects of 

climate change on visibility. Multiple studies have documented the indirect impact of CO2 

pollution on surface air quality. The warmer temperatures of climate change alter atmospheric 

chemistry and dynamics in ways that lead to generally higher ground-level ozone and PM2.5 

concentrations. 

In particular, a recent study from Princeton University indicates that the United States is or will 

experience increases in ozone and PM2.5 associated with climate change;12 this conclusion is 

generally consistent with other research on this topic.13 The analysis isolates the effects of 

climate change alone on surface air quality (as opposed to changes due to population growth, 

variations in emissions, etc.). In the U.S., it documents increases in PM2.5 of up to 2 ug/m3 

annually – roughly 17% of the current PM2.5 National Ambient Air Quality Standards 

(“NAAQS”). The highest increases are in the eastern U.S. Changes in ozone concentration are 

more varied, but the Princeton findings suggest increases of up to 2 ppbv in the northeast United 

States (nearly 3% of the current ozone NAAQS). 

In addition to threatening the attainment and maintenance of the NAAQS, these climate-change 

induced increases in ozone and PM2.5 impact regional haze. PM2.5 is the major source of haze 

pollution in the country. Additionally, projected increases in humidity would further exacerbate 

the haze-producing effects of any sulfate (or nitrate) present. Increases in ozone are also 

associated with lower visibility.14

Most significantly, these CO2-related changes in surface air quality cause increased mortality 

and other health impacts. In North America, PM2.5 and ozone increases due to climate change 

are expected to increase related mortality by 8% and 2%, respectively – in total an increase of 

nearly 13,000 deaths annually. The indirect impacts of climate change on air quality in 

California’s national parks – including impacts to visitor health and experience – are already 

being felt and will be further exacerbated without intervention. We encourage EPA to consider 

the effect of greenhouse gases on California’s efforts to mitigate visibility impairing pollution 

and act as needed to compensate for related impacts as a part of the state’s regional haze plan. 

e. EPA Checklist for 40 C.F.R § 51.308(g)(6): Does the Report include an 

assessment of whether the state’s haze plan is on track to meet reasonable 

progress goals?

40 C.F.R § 51.308(g)(6) mandates an “assessment of whether the current implementation plan 

elements and strategies are sufficient to enable the State, or other States with mandatory Federal 

 

12 Y. Fang (2013), “Impacts of 21st Century Climate Change on Global Air Pollution-Related Premature Mortality,” 

Climate Change 121:239-253.

13 See, e.g., M. Z. Jacobson (2008), “On the Causal Link Between Carbon Dioxide and Air Pollution Mortality,” 

Department of Civil and Environmental Engineering, Stanford University. 

14 V.P. Aneja (2004), “Ozone and Other Air Quality-Related Variables Affecting Visibility in the Southeast United 

States,” J. Air & Waste Manage. Assoc. 54:681–688. 
12

Class I areas affected by emissions from the State, to meet all established reasonable progress 

goals.” While California appears to be on track to meet its reasonable progress goals in most of 

its Class I areas (LAVO is an obvious exception, discussed below), it is not clear that this 

progress is enforceable or permanent. To retain this progress, we encourage EPA to revise 

California’s reasonable progress goals downward to reflect the progress thus far. We note that 

California previously committed to “reevaluat[ing] the RPGs” as a part of the Progress Report

“to determine if they should be adjusted to better reflect achievable improvements in visibility, 

as future control measures are adopted and implemented...(CRHP, Section 9.3, page 9–2).” 76 

FR 13961. We believe this is an appropriate juncture at which to assess California’s reasonable 

progress goals. 

f. EPA Checklist for 40 C.F.R § 51.308(h): Determination of Adequacy: Does 

the report (or the transmittal materials) provide the explicit determination 

required by the Regional Haze Rule?

This final step in the regulatory requirements for progress reports compels states to take one of 

four actions based on the information in the progress report. The first option, designed for 

situations where “visibility and emissions trends indicate substantial progress,” allows states to 

declare that further revision is not needed at this time.15 The remaining three options deal with 

situations where emissions – from other states, other countries, or the state itself, respectively –

are or may be inadequate to ensure reasonable progress. 

Given California’s identification of wildfire, shipping emissions, and Asian dust as relatively 

significant factors – particularly with regard to the LAVO monitor, which has seen degradation 

of visibility on the worst days – EPA should not approve California’s determination of adequacy. 

It is clear that this monitor is not on track to meet its reasonable progress goals and that the SIP 

as it stands is not sufficient to meet the established visibility goals. 

g. EPA Checklist for 40 C.F.R § 51.308(g)(7): Does the report review the 

monitoring plan including any non-IMPROVE monitors the state is using?

We encourage EPA to continue, if not increase, funding for the IMPROVE monitoring network. 

We note that many of California’s Class I areas are not monitored themselves but rely on data 

from another Class I area. To the extent feasible we encourage EPA to increase monitoring such 

that each Class I area has at least one dedicated monitor and at a minimum, the existing 

monitoring network should be maintained. 

V. SOURCES TO EVALUATE IN FUTURE REVISIONS

We encourage EPA and California to begin to identify potential sources of emission reductions 

for the 2018 SIP revision, including identifying where monitoring or inventory gaps exist, such 

that additional information can be developed. For instance, there were a number of BART 

eligible sources that were determined not to be subject to BART because their impacts were less 

than 0.5 deciviews. Some of these sources nonetheless had non-negligible impacts that California 

 

15 EPA April 2013, General Principles for the 5-Year Regional Haze Progress Reports for the Initial Regional Haze 

State Implementation Plans (Intended to Assist States and EPA Regional Offices in Development and Review of the 

Progress Reports), p. 18.
13

should revisit in 2018. Likewise, California does not appear to have performed single-source 

analysis for non-BART point sources. We encourage it to do so. 

Finally, we are aware that the transportation and agricultural sectors are collectively large 

sources of visibility impairing emissions. We encourage EPA and the State to begin assessment, 

identification of mitigation options, and a plan for mitigating emissions from these source 

categories in the 2018 SIP. As part of this, we encourage any monitoring or refinement necessary 

to ensure that the myriad agricultural emission sources are accurately captured. 

Thank you for the opportunity to comment on EPA’s proposed approval of California’s 

determination that its current regional haze plan is adequate to meet existing visibility goals.

Sincerely,

Nathan Miller

Engineering and Science Manager, Clean Air Program

National Parks Conservation Association

nmiller@npca.org