SUBMITTED VIA UPLOAD AT REGULATIONS.GOV 

August 31, 2012 

Attn: Docket No. EPA–HQ–OAR–2007–0492 

Environmental Protection Agency 

Mail Code 6102T 

1200 Pennsylvania Ave., NW. 

Washington, DC 20460 

Re: Comment on National Ambient Air Quality Standards for Particulate Matter; 

Proposed Rule, 77 Fed. Reg. 38890, 38991 (June 29, 2012) (EPA-HQ-OAR-2007–

0492) 

The Center for Biological Diversity (“Center”) submits the following comments 

regarding the EPA’s proposed National Ambient Air Quality Standards (“NAAQS”) for 

particulate matter (“Proposed Rule”)1

. The EPA is proposing to revise the annual primary 

NAAQS for PM2.5 to a limit in the range of 12 to 13 μg/m3

 while retaining the 24-hour primary 

standard of 35 μg/m3. The proposed rule would retain the current secondary standards for PM2.5

but add a new visibility standard. The primary and secondary standards for PM10 would remain 

unchanged. 

The Center is a non-profit organization with more than 375,000 members and online 

activists and offices throughout the United States. The Center’s mission is to ensure the 

preservation, protection and restoration of biodiversity, native species, ecosystems, public lands 

and waters and public health. In furtherance of these goals, the Center’s Climate Law Institute 

seeks to reduce U.S. greenhouse emissions and other air pollution to protect biological diversity, 

the environment, and human health and welfare. 

We support Administrator’s proposal to revise the primary PM2.5 standard in order to 

protect public health and welfare. As detailed below, however, the proposal should be improved 

in several important ways. First, the Administrator should adopt an annual PM2.5 standard of 11 

μg/m3 and revise the 24-hour PM2.5 standard to 25 μg/m3 in order to achieve the requisite health 

and welfare protection.2 Better speciated monitoring of ultrafine and fine particles is also 

essential, especially near roadways. 

Second, the revision must protect against both the direct health and the climate impacts of 

black carbon (“BC”), a component of PM that is a potent greenhouse pollutant and responsible 

 

1

 National Ambient Air Quality Standards for Particulate Matter; Proposed Rule, 77 Fed. Reg. 38890, 38991 (June 

29, 2012) (EPA-HQ-OAR-2007–0492) (hereinafter “Proposed Rule.”) 

2

 See Clean Air Task Force, Testimony of John Graham, Ph.D. Senior Scientist Regarding Proposes Revisions to the 

National Ambient Air Quality Standards for Particulate Pollution EPA-HQ-OAR-2007_0492 (July 17, 2012). 
August 31, 2012 Page 2 of 29 

Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

for climate warming, melting of ice and snow, and climate disruption. Black carbon also has 

significant negative effects on public health including cardiovascular and neurodegenerative 

effects and mortality. In fact, the data show that black carbon, especially from transportation 

sources, is one of the components of PM2.5 that is most harmful to public health. Thus the 

Administrator should set a separate limit for black carbon within the overall PM2.5 standard. This 

will ensure that the standards fully protect human health and welfare both from the direct health 

effects of PM2.5 inhalation and from the serious climate impacts of black carbon. Black carbon 

reductions present an enormous opportunity for climate mitigation in the near-term due to its 

short atmospheric lifetime. 

Finally, the proposal to “grandfather” in pending PSD permit applications already 

released for public comment as of the date of the revised NAAQS is contrary to the law and 

should be withdrawn. 

I. REGULATORY OVERVIEW 

The Clean Air Act (“CAA” or “Act”) is designed to protect human health and welfare 

and has been extremely successful. For example, a recent study indicated that by year 2020 the 

CAA will have produced health and welfare benefits worth over $2 trillion, and that those 

benefits exceed the costs of the regulations by more than 30 times.3

 The NAAQS program, 

which creates national standards for a select number of “criteria air pollutants,” is in many ways 

the heart of the Act’s protections. These standards are, in turn, implemented by the states in their 

state implementation plans. To ensure that the NAAQS remain effective, the EPA is required to 

review, and if necessary revise, the standards for each criteria air pollutant every five years.4

Like the rest of the Act, the NAAQS program is premised on the precautionary principle.5 

The Act directs the EPA, as the administering agency, to set the “primary” NAAQS at levels that 

“allowing an adequate margin of safety, are requisite to protect the public health.”6 The 

“secondary” NAAQS must specify levels that are “requisite to protect the public welfare from 

any known or anticipated adverse effects associated with the presence of such air pollutant in the 

ambient air.”7

 Public welfare is defined broadly to include, among others, effects on climate.8 

The courts have indicated that the “EPA must err on the side of caution ... setting the 

NAAQS at whatever level it deems necessary and sufficient to protect the public health with an 

adequate margin of safety, taking into account both the available evidence and the inevitable 

scientific uncertainties.”9

 Precaution is required for secondary NAAQS: 

 

3

 USEPA, The Benefits and Costs of the Clean Air Act from 1990 to 2020 Final Report (April 2011). 4

 42 U.S.C. § 7409(d)(1). 

5

 As discussed by the court in Lead Industries Association v. EPA, 647 F.2d 1130, 1152 (D.C. Cir. 1980): 

For example, the House Report accompanying the Amendments states that one of its purposes is "(t)o 

emphasize the preventive or precautionary nature of the act, i.e., to assure that regulatory action can 

effectively prevent harm before it occurs; to emphasize the predominant value of protection of public 

health(.)" H.R.Rep.No.95-294, 95th Cong., 1st Sess. 49 (1977). 6

 42 U.S.C. § 7409(b)(1). 

7

 42 U.S.C. § 7409(b)(2). 

8

 42 U.S.C. § 7602(h). 

9 American Trucking Associations, Inc. v. EPA, 283 F.3d 355, 369 (D.C. Cir. 2002).
August 31, 2012 Page 3 of 29 

Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

[N]othing in the Clean Air Act requires EPA to wait until it has perfect 

information before adopting a protective secondary NAAQS. Rather, the Act 

mandates promulgation of secondary standards requisite to protect public welfare 

from any "anticipated adverse effects associated with" regulated pollutants, 42 

U.S.C. § 7409(b)(2) (emphasis added), suggesting that EPA must act as soon as it 

has enough information (even if crude) to "anticipate[]" such effects[.]10

II. THE PROPOSED RULE FAILS TO ADEQUATELY CONSIDER THE 

SIGNIFICANT CLIMATE IMPACTS OF BLACK CARBON 

Black carbon is a potent short-lived pollutant with climate impacts that may be second 

only to carbon dioxide over the next 20 years.11 As such, it has received international attention 

as an important part of short-term actions to stave off immediate climate catastrophe and avoid 

imminent tipping points. Black carbon, or soot, is a product of incomplete combustion. It is 

typically co-emitted with organic carbon; the ratio of black carbon to organic carbon is highest 

for fossil fuels. Both black carbon and organic carbon are components of particulate matter. 

As outlined in the Proposed Rule, aerosols have a significant impact on climate.12 

Aerosols such as sulfates and nitrates exert a cooling impact on climate through cloud processes. 

In contrast, black carbon exerts a powerful warming influence on climate through a variety of 

mechanisms. This rulemaking presents an opportunity to mitigate global warming: a speciation 

approach that sets protective limits for black carbon will reduce warming in the next two 

decades, yet the proposed rule would forego this critically needed protection. 

 The proposed rule and the associated Integrated Science Assessment have also failed to 

fully consider all of the relevant data related to climate impacts of black carbon. Furthermore, 

these documents in some instances inaccurately characterize the state of the science. 

A. The Current Rulemaking has Omitted Consideration of Current Science 

Related to Black Carbon 

The climate science reviewed in the proposed rule and supporting documents is not up to 

date, and this has impeded the Agency’s decision making process with regard to black carbon. 

Research studies that have contributed important new information within the last 5 years were 

not reviewed in the current rulemaking. For instance, estimates of black carbon’s radiative 

forcing have improved. Furthermore, the science review fails to capture important aspects of 

black carbon effects on snow and ice. The importance of climate change in the Arctic, especially 

with regard to short-lived pollutants is also not reviewed in sufficient depth. The importance of 

 

10 Id. at 380. 

11 V. Ramanathan, & G. Carmichael, Global and Regional Climate Changes due to Black Carbon, 1 Nature 

Geoscience (2008) (“Ramanathan and Carmichael 2008”) at 221; USEPA, Policy Assessment for the Review of the 

Particulate Matter National Ambient Air Quality Standards (April 2011) at 5-10. Methane, the second most potent 

well-mixed greenhouse gas has a radiative forcing of 0.48 W/m2

 according to the IPCC Fourth Assessment. This 

means that current observational estimates of black carbon forcing are larger than the forcing estimated for methane. 

These estimates are discussed in greater detail below. 12 Proposed Rule at 38991. 
August 31, 2012 Page 4 of 29 

Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

avoiding tipping points has not been elucidated. Finally, welfare concerns related to decreased 

water availability have not been sufficiently considered. 

1. Improved Estimates of Black Carbon Radiative Forcing 

One of the fundamental characteristics of a climate pollutant is the amount that it 

contributes to global warming. This is often characterized as radiative forcing. The Proposed 

Rule cites to the radiative forcing value assigned by the Fourth Assessment Report of the 

Intergovernmental Panel on Climate Change (0.2 W/m2

).13 This report was published in 2007. 

Since then, a number of studies have refined the methods used to estimate radiative forcing for 

black carbon and have derived values higher than that reported in the IPCC Fourth Assessment 

Report (“IPCC AR4”). One explanation relates to the mixing state of black carbon. Black 

carbon particles are “externally mixed” if they occur as pure black carbon, whereas they are 

referred to as “internally mixed” if they occur as a complex of black carbon plus other 

compounds, such as sulfates. This is important because black carbon becomes internally mixed 

as it remains in the atmosphere, which increases the heating efficiency of black carbon. Some of 

the IPCC’s AR4 models used to estimate black carbon’s radiative forcing neglected to account 

for internal mixing. Model estimates since the IPCC AR4 include Bond et al., who arrived at a 

direct radiative forcing value of 0.4 W/m2

 for anthropogenic black carbon based on an average of 

12 models.14 Another model estimated black carbon forcing to be 0.53 W/m2.

15 

Ramanathan and Carmichael report an observationally constrained value of direct 

radiative forcing for black carbon of 0.9 W/m2

.

16 These authors explained that general 

circulation models used to obtain the generally lower values of forcing for black carbon (1) 

neglect mixing of black carbon with sulfates and other compounds, which increases forcing 

significantly due to a lensing effect; (2) do not account for differences in black carbon 

concentrations at higher elevations in the air column where the black carbon can influence cloud 

reflectivity; and (3) neglect biomass burning.17 

Chung and Seinfeld recently reported observational estimates of direct radiative forcing 

for both black carbon and organic matter from biomass burning. They estimate direct radiative 

forcing for black carbon to be 0.65 W/m2

 and the contribution of organic carbon to be 0.0 W/m2

due to the offsetting balance of absorption by brown carbon and light scattering.18 Furthermore, 

these authors estimate that indirect effects approximately cancel as well, with the result that the 

black carbon forcing will dictate the forcing from pollutants emitted by biomass burning. This is 

a crucial difference from the assumptions made in the Proposed Rule. The Proposed Rule 

assumes that radiative forcing for biomass burning is close to zero (0.03 W/m2

).19 If this flawed 

 

13 Proposed Rule at 38991. 

14 Bond, T.C. et al., Quantifying Immediate Radiative Forcing by Black Carbon and Organic Matter with the 

Specific Forcing Pulse, 11 Atmos. Chem. Phys. 1505 (2011). 

15 Ming, Y et al., Two Opposing Effects of Absorbing Aerosols on global-mean Precipitation, 37 Geophys. Res. 

Lett. L13701 (2010) at 2. 

16 Ramanathan and Carmichael 2008, citing Chung et al. 2005. 

17 Id. 18 Chung, Serena and John Seinfeld, Climate Response of Direct Radiative Forcing of Anthropogenic Black Carbon, 

110 Journal of Geophys. Res. D11102 (2012) (“Chung and Seinfeld 2012”) at 4. 

19 Proposed Rule at 38992. 
August 31, 2012 Page 5 of 29 

Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

assumption is retained, it will contribute to further flawed decisions regarding the climate 

impacts of aerosols from biomass burning. 

The discrepancy between the value assumed in the Proposed Rule and the direct radiative 

forcing for black carbon estimated by more recent, accurate techniques is significant. In the 

Proposed Rule, the total direct radiative forcing for all aerosols combined is assumed to be only 

-0.5 W/m2

; indirect aerosol forcings due to cloud effects, -0.7 W/m2 and total radiative forcing 

for all aerosols -1.3 W/m2.

20 The observationally constrained values for black carbon indicate 

that the assumed net cooling associated with aerosols is up to 50% less than predicted due to the 

presence of black carbon.21 The Integrated Science Assessment discusses in detail the limits of 

model-based estimates for aerosol climate forcing.22 As a result, the EPA should weight these 

observational values for black carbon forcing more heavily than model-based values. 

 

2. Black Carbon Effects on Snow and Ice 

Another crucial omission from the Proposed Rule and the ISA is the effect of reduced 

snow and ice albedo. The Integrated Scientific Assessment (ISA) devoted most of the climate 

section to in-depth analysis of the impact of aerosols on clouds and the resultant direct and 

indirect forcings. Yet, there was no attempt to quantify the forcing due to the reduction in snow 

and ice albedo. The Integrated Science Assessment states that “Other indirect effects from 

aerosols are not considered to be radiative forcing.”23 This appears to be an inaccurate 

statement: the scientific literature universally treats albedo changes as a forcing ― and a 

significant one at that. For instance, Andrews and colleagues estimate that the indirect radiative 

forcing of black carbon on snow is 0.28 W/m3.

24 Another study estimated the radiative forcing 

of black carbon on snow and ice at 0.054 and 0.049 W/m2 for a strong and weak year.25 Flanner 

et al. recently used an observational approach to assess how much snow albedo has changed 

between 1979 and 2008. They concluded that the change in albedo forcing was approximately 

0.45 W/m2

 over this time span.26 Furthermore, this study suggests that models typically 

underestimate the sensitivity of snow and ice albedo changes as a driver of atmospheric 

warming.27

Perhaps more important than the radiative forcing exerted on snow and ice is the efficacy 

of the forcing. “Efficacy” refers to how much temperature will increase as a result of a given 

amount of radiative forcing. The Integrated Science Assessment refers to an estimated efficacy 

 

20 Proposed rule at 38992. 

21 Assuming a radiative forcing for black carbon of 0.9 W/m2

, the difference from the 0.2 W/m2 radiative forcing for 

black carbon used in the proposed rule is 0.7 W/m2

. This reduces total aerosol to -0.6 W/m2. 22 See, e.g., USEPA, Integrated Science Assessment for Particulate Matter (December 2009) (“ISA”) at 9-124. 23 ISA at 9-164. 

24 Andrews, T. et al., Precipitation, Radiative Forcing and Global Temperature Change, 37 Geophys. Res. Lett. 

L14701 (2010) at 3. 

25 Flanner, Mark et al., Present-day Climate Forcing and Response from Black Carbon in Snow, 112 Journal of 

Geophys. Res. D11202 (2007) (“Flanner 2007”) at 9. 

26 Flanner, Mark et al., Radiative Forcing and Albedo Feedback from the Northern Hemisphere Cryosphere between 

1979 and 2008, Nature Geoscience Advance Online Edition (Jan 16, 2011) (“Flanner 2011”) at 2. 

27 Id. at 3-4. 
August 31, 2012 Page 6 of 29 

Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

of 1.7.28 More recent estimates suggest that in fact black carbon may have an efficacy of 3.2.29 

Furthermore, it is important to note that some particulate matter that would otherwise be 

considered “cooling”, e.g. organic matter, will have a heating effect over snow and ice because 

the pristine surface reflectivity (albedo) is so high that the particles will reflect less radiation than 

the snow and ice surface.30 

Feedbacks are particularly important over snow and ice. Black carbon has an even 

greater impact on seasonal snow and ice because it causes earlier exposure of underlying lowalbedo surfaces (e.g., rock, soil, vegetation and ocean).31 Over the course of the Arctic spring, 

black carbon-contaminated snow absorbs enough extra sunlight to melt earlier – weeks earlier in 

some places – than clean snow.32 As snow and ice surfaces continue to warm, melt, darken and 

lose contrast with black carbon, the net warming effect of black carbon on the Arctic will 

decrease.33 Thus, reducing black carbon now will have more of an impact than delaying 

reductions. 

Black carbon’s impact on the melting of snow and sea ice applies with equal force to the 

decrease in albedo of glaciers in montane regions and consequent accelerated melt-off. Black 

carbon depositions on Tibetan glaciers have been found to be a significant contributing factor to 

observed rapid glacier retreat.34 By increasing surface melt on ice masses, black carbon triggers 

positive feedbacks because the resulting melt water spurs multiple radiative and dynamic 

feedback processes that accelerate ice disintegration.35 Moreover, in the case of glaciers, by 

increasing water flow through crevasses and moulins, black carbon speeds freeze-thaw ice breakup and lubrication of the ice sheet base.36 

Pristine Antarctic regions have been found to contain black carbon concentrations of 0.1-

0.3 ppbw (parts per billion by weight), two orders of magnitude less than the Arctic.37 Notably, 

black carbon amounts of 3 ppbw were found 1 km downwind of the South Pole station, where 

the station’s power plant and aircraft operations were a suspected source.38 Snow samples in the 

1980s, including sites in Alaska and on sea ice in the central Arctic, yielded typical black carbon 

amounts of 10-50 ppbw.39 While black carbon emissions may have fallen in the 1990s due to the 

 

28 ISA at 9-162 citing Hansen, AC et al., Ethanol-diesel Fuel Blends – A Review, Bioresour Technol, 96:227-285. 

2005. 

29 Flanner 2007 at 10. 

30 Flanner, M.G. et al., Springtime Warming and Reduced Snow Cover from Carbonaceous Particles, 9 Atmos. 

Chem. Phys. 2481 (2009) (“Flanner 2009”). 

31 Joseph McConnell et al., 20th-Century Industrial Black Carbon Emissions Altered Arctic Climate Forcing, 317 

Science 1381, 1383 (2007). 

32 Zender, Charles, Arctic Climate Effects of Black Carbon, Written Testimony for Hearing Before the H. Comm. on 

Oversight and Gov’t. Reform on EPA Black Carbon and Global Warming, 110th Cong. 12-29 (2007) (“Zender 

Testimony”) at 72. 

33 Id. at 71 34 Xu, Baiqing et al., Black Soot and the Survival of Tibetan Glaciers, 106 Proc. Nat’l Acad. Sci. U.S. 22114 (2009), 

available at http://www.pnas.org/content/106/52/22114.full. 35 Hansen, James & Larissa Nazarenko, Soot Climate Forcing via Snow and Ice Albedos, 101 Proc. Nat’l Acad. Sci. 

423 (2004) at 427. 

36 Id. 37 Id. at 424. 38 Id. 39 Id. at 423. 
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Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

economic collapse of the former Soviet Union, reduced black carbon emissions are not 

necessarily permanent in the face of possible economic recovery, increased shipping in the 

opening Northwest and Northeast Passages, regional hydrocarbon resource development, and 

increased use of diesel-powered vehicles.40 Measurements in the Alps revealed black carbon 

concentrations as large as 100 ppbw, enough to reduce the visible albedo by approximately 10% 

and double absorption of sunlight.41 However, because of the positive feedbacks resulting from 

black carbon deposition, much smaller concentrations of black carbon perturb snowmelt. Even 

very small concentrations of black carbon impurities (~ 10 ppb) are triggering astonishingly 

large ice-albedo warming.42 This effect at low black carbon concentrations was recently 

confirmed in a laboratory setting.43 This study also confirmed that as snow grains increase in 

size with age, they become more sensitive to black carbon-induced albedo reductions.44

3. The Importance of the Arctic 

 The Arctic is an area of particular importance with regard to black carbon. Although the 

Integrated Science Assessment includes a section on Arctic PM deposition, it fails to capture the 

importance of immediate reductions in atmospheric warming at this location. The Arctic has 

experienced some of the most severe and rapid warming associated with climate change, 

warming at twice the rate of the rest of the globe on average.45 Arctic summer sea ice extent and 

thickness have decreased to about half of what they were several decades ago,46 with an 

accompanying drastic reduction in volume,47 which is severely jeopardizing ice-dependent 

animals.48 Sea ice is disappearing at an unprecedented rate: ice extent on August 26, 2012 fell 

below the record low set in September 2007, with several weeks of ice reduction likely still to 

come.49

Adverse impacts resulting from the accelerated loss of Arctic sea ice extend well beyond 

the Arctic Ocean and its coast. By reflecting the sun’s energy back into space, sea ice is an 

effective insulator, preventing heat in the Arctic Ocean from escaping upward and warming the 

 

40 Id. at 424. 41 Id. at 427. 42 Zender Testimony at 74. 43 Hadley, Odelle and Thomas Kirchstetter, Black-carbon Reduction of Snow Albedo, Nature Climate Change 

Advance Online Publication (March 4, 2012). 44 Id. at 437. 45 Trenberth, Kevin et al., Observations: Surface and Atmospheric Climate Change in Climate Change 2007: The 

Physical Sciense Basis - Contribution of Working Group I to the Fourth Assessment Report of the IPCC (Susan 

Solomon et al., eds. 2007). 

46 Stroeve, J. et al., Arctic Sea Ice Extent Plummets in 2007, 89 EOS 2 (January 8, 2008); R. Kwok and D.A. 

Rothrock, Decline in Arctic sea ice thickness from submarine and ICESat records: 1958-2008, 36 Geophys. 

Research Lett L15501 (2009). 

47 Polar Science Center, Arctic Sea Ice Volume Anomaly, version 2, 

http://psc.apl.washington.edu/wordpress/research/projects/arctic-sea-ice-volume-anomaly/ (last visited August 30, 

2012). 

48 Wolf, Shaye, Extinction: It’s Not Just for Polar Bears, Center for Biological Diversity and Care for the Wild 

International (2010). 49 National Snow and Ice Data Center (NSIDC), Arctic Sea Ice News and Analysis – Sea ice data updated daily, 

http://nsidc.org/arcticseaicenews/ (last visited August 30, 2012). 
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Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

lower atmosphere.50 The decline of sea ice amplifies warming in the Arctic, which in turn has 

major implications for temperature patterns over adjacent, permafrost-dominated land areas and 

for weather patterns across the Northern Hemisphere.51 Rapid retreat of Arctic sea ice is 

predicted to accelerate warming 1,500 kilometers inland throughout Alaska, Canada and 

Russia.52 During rapid ice retreat, the rate of inland warming could be more than three times that 

previously suggested by global climate models.53 Higher temperatures will thaw out extensive 

expanses of permafrost, resulting in the potential release of methane and carbon dioxide 

currently frozen in Arctic soils, thereby further accelerating additional warming.54 Additional 

warming in the Arctic resulting from the loss of sea ice will also affect weather patterns by 

altering atmospheric circulation patterns and, therefore, weather patterns, leading to more 

extreme weather events and affecting transportation, agriculture, forestry and water supplies.55 

Loss of sea ice in the Arctic Ocean will therefore have serious repercussions as climactic 

feedbacks resulting from higher temperature increases accelerate, the timing of the seasons is 

altered, and shifting circulation patterns cascade through the Arctic and beyond. 

 We must act immediately to reduce heating in the Arctic region. Waiting for reductions 

in carbon dioxide alone to take effect will be many decades too late. Reductions in black carbon 

are urgently needed to slow warming in the Arctic in the short term.56 

4. The Importance of Tipping Points 

Growing emissions have the potential to trigger “tipping points,” critical points in the 

climate system where even small increases in climate forcing trigger a rapid switch to a 

qualitatively different state that can be irreversible for millennia.57 Several “tipping elements” in 

the climate system are thought to be close to their triggering points. For example, a 0.8 to 3.2°C 

temperature rise above pre-industrial levels has the potential to trigger irreversible melting of the 

 

50 World Wildlife Fund Int’l, Arctic Climate Feedbacks: Global Implications 8 (Martin Sommerkorn & Susan Joy 

Hassol eds., 2009) at 19-20. 

51 Id. at 18. 

52 United Nations Environmental Programme, Climate Change 2009 Science Compendium 19 (2009). (“UNEP 

2009”) The disappearance of the Arctic ice cap during the sunlit period of the year would radically reduce the local 

albedo and cause an annually averaged 19.7 Wm−2

 increase in absorbed solar flux at the Arctic Ocean surface, or 

equivalently an annually averaged 0.55 Wm−2

 increase on the planetary scale. C. Matsoukas et al., The Effect of 

Arctic Sea-Ice Extent of the Absorbed (Net) Solar Flux at the Surface, Based on ISCCP-D2 Cloud Data for 1983-

2007, 10 Atmospheric Chemistry & Physics 777, 777 (2010). 53 UNEP 2009 at 19. 54 Id. 55 Francis, J. and Stephen Vavrus, Evidence Linking Arctic Amplification to Extreme Weather in Mid Latitudes, 39 

Geophys. Res. Lett. L06801 (2012). 

56 See, e.g., Arctic Council Task Force on Short-Lived Climate Forcers, An Assessment of Emissions and Mitigation 

Options for Black Carbon for the Arctic Council (2011) (“ACTF SLP Report 2011”); Jacobson, Mark, Short-term 

effects of Controlling Fossil-fuel soot, biofuel Soot and Gases, and Methane on Climate, Arctic Ice, and Air 

Pollution Health, 115 Journal of Geophys. Res. D14209 (2010) (“Jacobson 2010”); Ramanathan, V. & Yangyang 

Xu, The Copenhagen Accord for limiting Global Warming: Criteria, Constraints, and Available Avenues, 107 Proc. 

Natl. Acad. Sci. 18 (2010) (“Ramanathan & Xu 2010”). 

57 Lenton, Timothy et al., Tipping elements in the Earth's climate system, 105 Proc. Natl. Acad. of Sciences 1786 

(2008); Mario Molina et al., Reducing abrupt climate change risk using the Montreal Protocol and other regulatory 

actions to complement cuts in CO2 emissions, 106 Proc. Natl. Acad. of Sciences 20616 (2009); Schellenhuber, Hans 

Joachim ,Tipping elements in the Earth System, 106 Proc. Natl. Acad. of Sciences 20561 (2009). 
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Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

Greenland ice sheet, resulting in an eventual seven meters of sea-level rise that would inundate 

small island nations and heavily populated coastal areas.58 Climate forcing from rising 

greenhouse gas emissions also reinforces positive feedback cycles that can further amplify 

warming. In the Arctic, the ice-albedo feedback loop is already occurring, where the loss of 

highly reflective sea ice due to warming increases solar absorption, making the Arctic more 

vulnerable to future warming and ice loss. Increasing temperatures are expected to trigger other 

feedbacks including the release of large stores of carbon and the potent greenhouse gas methane 

from melting Arctic permafrost.59 

Reductions in black carbon can help avoid crossing over tipping elements that are close 

to threshold. As discussed above, black carbon is one of the most important climate pollutants in 

the Arctic. Additionally, North America is the largest contributor to black carbon deposited on 

Greenland.60

5. Decreased Water Availability with Black Carbon-Induced Snow Melt 

 Another public welfare implication of black carbon-induced snow melt is water 

availability. Glaciers and ice caps cover 10% of the Earth’s surface and provide about 75% of 

the world’s fresh water.61 The glaciers of the continental U.S. have a total area of approximately 

580 sq. km62 and constitute 7% of world glacier area.63 Washington State accounts for 

approximately 75% of U.S. glacial extent outside of Alaska.64 Alaska contains approximately 

11% of world glacier area.65 Like sea ice, the Earth’s glaciers as a whole are exhibiting rapid 

recession.66 For example, the number of glaciers at Glacier National Park has dropped from 150 

to 26 since 1850, and if current trends in the rate of melting continue, the remaining glaciers will 

disappear within the next 25 to 30 years.67

One of the main services provided by glaciers is water storage. Water storage occurs 

both as frozen water in the form of ice as well as precipitation stored in glacial aquifers.68 In 

many areas summer melt provides a regulating influence to maintain stream flows during the dry 

 

58 Robinson, Alexander et al., Multistability and critical thresholds of the Greenland ice sheet, 2 Nature 429 (2012). 59 David Archer et al., The Millennial Atmospheric Lifetime of Anthropogenic CO2, 90 Climatic Change 283, 22 

(2008); Charles D. Koven et al., Permafrost carbon-climate feedbacks accelerate global warming, 108 Proc. Natl. 

Acad. of Sciences 14769 (2011). 

60 Shindell, D.T. et al., A multi-model Assessment of Pollution Transport to the Arctic, 8 Atmos. Chem. Phys. 5353 

(2008) at 5361. 

61 P. Jansson et al., The Concept of Glacier Storage: a Review. 282 J. Hydrology 116, 117 (2003) (“Jansson 2003”). 62 Id. at 329. 63 R.G. Barry, The Status of Research on Glaciers and Global Glacier Recession: A Review, 30 Progress in Physical 

Geography 285, 286 (2006) (“Barry 2006”). 

64 Krimmel, Robert, Glaciers of the Conterminous United States, U.S. Geological Survey Professonal Paper 1386-J2 (2002) see Table 1 for individual states. 65 Barry 2006 at 286. 

66 P. Lemke et al., Chapter 4, Observations: Changes in Snow, Ice and Frozen Ground in Climate Change 2007: The 

Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the 

Intergovernmental Panel on Climate Change 356 (S. Solomon et al. eds., 2007). 

67 See, e.g.,Government Accountability Office, Climate Change: Agencies Should Develop Guidance for Addressing 

the Effects on Federal Land and Water Resources 18 (Aug. 2007), available at: 

http://www.gao.gov/news.items/d07863.pdf. 68 Jansson 2003 at 119-22. 
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Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

season.69 The importance of glacial water sources operates at multi-year, seasonal, and daily 

time scales.70 Non-ice sheet glaciers are also significant because they can change extent much 

more rapidly than ice sheets, and thus are the current greatest contributor to increases in sea 

level.71 In fact, it is estimated that the world’s non-ice sheet glaciers would cause a 0.65 ± 0.16 

m rise in sea level if they melted completely.72 Glacial water storage and release also has 

important implications for hydroelectric power plants, irrigation, consumptive use, and local 

ecosystems.73 Decreasing summer runoff will result in lower water levels in lakes and rivers, 

which in turn will cause re-suspension of sediment and free harmful compounds within the 

sediment.74 Destabilization due to glacial retreat can also increase the risk of “geomorphic 

hazards” such as floods, avalanches, and debris flow.75 

Similarly, black carbon deposited on seasonal snow can induce early melt and reduce 

water availability. A recent study measured significant concentrations of black carbon within 

falling snow in the Sierra Nevada.76 This black carbon in turn would induce earlier snow melt 

due to changes in albedo and directly impact California’s water supply, which is currently 

impaired. 

 

B. The “Unmasking” of Greenhouse Warming Due to Reductions in Cooling 

Aerosols Can be Offset by Reductions in Black Carbon 

As evident from the scientific literature reviewed in the Integrated Science Assessment, 

there are significant health impacts from aerosols that can be ameliorated only with reductions in 

particulate matter. Further improvements in air quality are obviously needed from a direct health 

perspective. However, reductions in PM emissions overall could “unmask” some of the current 

net cooling effect of aerosol pollution if black carbon reductions do not account for a sufficient 

proportion of overall reduction in PM. The solution is to ensure that sufficient black carbon 

reductions accompany reductions in overall aerosol pollution. This will not ensure not only a 

climate benefit, but additional direct health benefits as well. 

The problem of “unmasking” global warming due to sulfate reductions has been the focus 

of multiple policy and scientific reports.77 For instance, mitigation options to simultaneously 

reduce global warming and benefit public health as outlined by Shindell et al. specifically 

 

69 Moore 2009 at 48. 

70 Jansson 2003 at 117-19, 123. 

71 Id. at 118. 72 M.B. Dyurgerov & M.F. Meier, Glaciers and the Changing Earth System: A 2004 Snapshot at 7, Occasional Paper 

58 (2005): Institute of Arctic and Alpine Research, University of Colorado. 

73 Moore 2009. 

74 Z.W. Kundzewicz et al, Chapter 3, Freshwater Resources and their Management in Climate Change 2007: The 

Physical Science Basis. Contribution of Working Group II to the Fourth Assessment Report of the 

Intergovernmental Panel on Climate Change 188 (M.L. Parry et al. eds., Cambridge Univ. Press 2007). 75 Moore 2009 at 50. 

76 Hadley, O.L. et al., Measure Black Carbon Deposition on the Sierra Nevada Snow Pack and Implication for Snow 

Pack Retreat, 10 Atmos. Chem. Phys. 7505 (2010). 

77 See, e.g., United Nations Environment Program (UNEP), Integrated Assessment of Black Carbon and Troposheric 

Ozone (2011) (“UNEP SLP Report 2011”) at 8; Ramanathan, V. and Y. Feng, On Avoiding Dangerous 

Anthropogenic Interference with the Climate System: Formidable Challenges Ahead, 105 Proc. Natl. Acad. Sci. 38, 

14245-14250(2008) (“Ramanathan and Feng 2008”). 
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Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

avoided measures that reduce sulfates.78 Similarly, Ramanathan and Xu emphasize the fact that 

cooling aerosols have masked up to 50% of the atmospheric heating that would otherwise occur 

due to current levels of greenhouse gases in the atmosphere.79 

Yet, current regulations in the United States and globally are likely to significantly reduce 

sulfates and other reflective aerosols.80 A recent study examined patterns of greenhouse gas and 

aerosol emissions and determined that the recent unprecedented warming in the Arctic in large 

part results from the combined effect of reduced sulfates and increased black carbon emissions.81 

Absent measures to ensure balanced reductions in absorbing and scattering aerosols, it is 

possible that reductions in overall PM2.5 could have a warming effect. This carries not only 

public welfare implications, but also public health implications. Yet the Proposed Rule and 

supporting documents do not consider the negative consequences of climate change on public 

health. 

Climate change poses an increasing threat to human health, through increases in heat 

waves and other extreme weather events, ailments caused or exacerbated by air pollution and 

airborne allergens, and the increased occurrence of climate-sensitive infectious diseases.82

Certain groups such as children, the elderly, the poor, and minorities are particularly vulnerable 

to climate-related health effects.83 

The number and intensity of extreme weather events are already increasing and are 

projected to increase further in the future, leading to increases in associated injury, illness, 

emotional trauma, and death.84 Heat is already the leading cause of weather-related deaths in the 

United States, and one recent study estimated that more than 150,000 Americans may die by the 

end of the century due to excessive heat caused by climate change.85 Heat-wave related deaths in 

Chicago would more than double by 2050 under a lower emissions scenario and quadruple under 

a high emissions scenario, while in Los Angeles, annual heat-related deaths are projected to 

increase by two to three times by the end of the century under a lower emissions scenario and by 

five to seven times under a higher emissions scenario, compared to a 1990s baseline.86 Extreme 

precipitation, which has increased in the Midwest, South and other regions by 50% mostly over 

the last few decades,87 poses significant human health risks including contaminated drinking 

water leading to disease outbreaks, drowning, and mold-related illnesses.88An increase in the 

intensity of Atlantic hurricanes would also have severe health risks. More than 2,000 Americans 

 

78 Drew Shindell et al., Simultaneously Mitigating Near-term Climate Change and Improving Human Health and 

Food Security, 335 Science 183 (2012) (“Shindell 2012”) at 183. 

79 Ramanathan and Xu 2010 at 805. 

80 Id. at 8059; Ramanathan and Feng 2008 at 14246. 81 Shindell, Drew & Greg Flaugevi, Climate Response to Regional Radiative Forcing During the Twentieth 

Century, Nature Geoscience, Online Publication (Mar. 31, 2009) at 298. 

82 U.S. Global Change Research Program, Global Climate Change Impacts in the United States (2009) (“USGCRP 2009”). 83 Id. 84 Id. 85 Natural Resources Defense Council, Killer Summer Heat: Toll form Rising Temperatures in America due to Climate Change 

(2012). 

86 USGCRP 2009. 

87 Id. 88 Union of Concerned Scientists, After the Storm: The Hidden Health Risks of Flooding in a Warming World (2012), available

at www.ucsusa.org/global_warming/science_and_impacts/impacts/global-warming-and-flooding.html. 
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Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

were killed in the 2005 hurricane season, more than double the average number of lives lost to 

hurricanes in the United States over the previous 65 years.89

Air pollution components that trigger asthma attacks, specifically air particulates and 

ozone, are expected to increase with climate change.90 Asthma remains a leading cause of 

morbidity and school absenteeism in the United States. Projected climate-related increases in 

ground-level ozone concentrations in 2020 could lead to an average of 2.8 million more 

occurrences of acute respiratory symptoms, 944,000 more missed school days, and over 5,000 

more hospitalizations for respiratory-related problems.91 In 2020, the continental U.S. could pay 

an average of $5.4 billion (2008$) in health impact costs associated with the climate penalty on 

ozone, with California experiencing the greatest estimated impacts averaged at $729 million.92 

Infectious diseases also pose an increased threat in a changing climate. There are an 

estimated 38 million cases of food and water-borne illness in the US each year, caused in part by 

an increasing number of pathogens in the wake of extreme weather events such as droughts, 

flooding, and hurricanes.93 Meanwhile, warming favors the spread of some pathogen-carrying 

vectors. Lyme disease is the most common vector-borne disease in the United States, with 

25,000–30,000 cases reported to the CDC per year, with the highest incidence among children 

between ages 5 and 9. 94 A recent study suggests that outbreaks of the vector-borne West Nile 

Virus are potentially related to higher summer temperatures and extreme variation in 

precipitation.95 

A balance of black carbon and total aerosol reductions will protect public health and 

welfare. Because black carbon has a short atmospheric lifetime of 5-7 days, reductions in black 

carbon are an effective and immediate means to ensure that reductions in “cooling” aerosols such 

as sulfates and nitrates do not inadvertently exacerbate the current trends in global warming. In 

addition, as discussed above, the net radiative forcing due to direct and indirect effects of black 

carbon is of a similar order of magnitude as the cooling contributed by sulfates and nitrates. 

C. The EPA Must Address the Impacts of Black Carbon in the PM NAAQS, Even 

in the Face of Some Remaining Uncertainties 

 

89 USGCRP 2009. 90 A. Bernstein & S.S. Myers, Climate Change and Children’s Health, 23 Current Opinion in Pediatrics 221 (2011) 

(“Bernstein 2011”), available at http://journals.lww.com/copediatrics/Fulltext/2011/04000/Climate_change_and_children_s_health.16.aspx#. 91 E. Perera & T. Sanford, Union of Concerned Scientists, Climate Change and Your Health: Rising Temperatures, 

Worsening Ozone Pollution, 2 (2011), available at www.ucsusa.org/assets/.../global..../climate-change-and-ozonepollution.pdf. 92 Id. 93 E. Maibach et al., Center for Climate Change Communication, Conveying the Human Implications of Climate 

Change, 10-11 (2011), available at http://www.climatehealthconnect.org/resource/conveying-human-implicationsclimate-change-climate-change-communication-primer-public-heal. 94 Bernstein 2011. 

95 Shlomit Paz, West Nile Virus Eruptions in Summer 2010 – What Is the Possible Linkage with Climate Change?, 

Chapter 21 of National Security and Human Health Implications of Climate Change 253 – 260 (2012). 
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Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

 The climatic effects of black carbon are well-established. Yet the Integrated Science 

Assessment repeatedly focuses on the unknowns related to aerosol climate science. What little 

mention is made of black carbon repeats this theme. While it is true that there are still details 

related to aerosol and black carbon climate impacts on which further research is needed, the 

necessary facts are known. The EPA has a statutory obligation to take action. 

 Black carbon has received international attention as a critical component of rapid action 

to address climate change. The United Nations Environment Programme recently released an 

assessment report that outlined the importance of black carbon and methane reductions for 

protecting public health and staying within the world’s commitment to keep global temperature 

changes below 2° C.96 Furthermore, the identified mitigation strategies if implemented by 2030

could cut global temperature increases in half by 2050.97 Similarly, the Arctic Council Task 

Force on Short-Lived Climate Forcers, formed by the Arctic Council Ministerial Tromsø 

Declaration, recently published an assessment report outlining the importance of reducing black 

carbon to protect the Arctic as well as protect public health globally.98 The United States is also 

a member of the Climate and Clean Air Coalition, which focuses on reductions in short-lived 

pollutants such as black carbon to mitigate climate change, prevent deaths, and improve food 

security.99

 The United States also has an obligation under the Gothenburg Protocol to address black 

carbon pollution.100 The Gothenburg Protocol is part of the Convention on Long-Range 

Transboundary Air Pollution. The United States has ratified this treaty. The Gothenburg 

Protocol sets particulate matter ceilings for European countries, although the United States is not 

subject to these ceilings. On May 4, 2012 the Protocol was amended to specifically address 

black carbon as a constituent of fine particulate matter. These revisions to the Protocol 

emphasize the importance of reducing black carbon to protect public health and climate. 

Furthermore, members agree to choose mitigation options for particulate matter that focus on 

black carbon reductions. 

 The EPA was tasked with generating a report on black carbon for Congress as part of the 

Department of Interior Appropriations Act of 2010.101 This report shows that EPA is aware of 

the climate science and public health information that point to the importance of addressing 

black carbon pollution.102 EPA must use this information in its relevant decsionmaking. 

 

96 UNEP SLP Report 2011. 

97 UNEP SLP report 2011 at 159. 

98 ACTF SLP Report 2011 and Arctic Council Task Force on Short-Lived Climate Forcers, Progress Report and 

Recommendations for Ministers (2011) (“ACTF SLP Report Summary 2011”). 

99 U.S. Department of State, The Climate and Clean Air Coalition to Reduce Sort Lived Climate Pollutants Fact 

Sheet (Feb 16, 2012), available at http://www.state.gov/r/pa/prs/ps/2012/02/184055.htm (Secretary Clinton remarks 

introducing the Coalition). 

100 UNECE, Protocol to Abate Acidification, Eutrophication and Ground-level Ozone done in Gothenburg, Sweden 

in 1999 (last visited August 31, 2012), available at http://www.unece.org/env/lrtap/multi_h1.html. The protocol 

was revised in May 2012 to include specific reference to black carbon abatement. 101 U.S. Congress, H.R. 2996: Department of the Interior, Environment, and Related Agencies Appropriations Act 

(2010). 

102 USEPA, Report to Congress on Black Carbon (March 2012) (“USEPA Black Carbon Report”). 
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Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

 Within the scientific community, multiple studies have indicated the importance of 

reducing black carbon and other short-lived climate pollutants. Bond and Sun as early as 2005 

published a study outlining the importance of reducing black carbon.103 Ramanathan and Xu 

outlined four actions necessary to meet the US commitment to the Copenhagen Accord. These 

actions relied in large part on reductions in short-lived pollutants such as black carbon.104 A 

complex climate model recently indicated that reducing fossil fuel and solid-biofuel black carbon 

was more effective at reducing Arctic short-term warming than reductions in either methane or 

carbon dioxide.105 Shindell and colleagues recently published a paper outlining 14 measures to 

reduce black carbon and methane that could reduce temperature increases in 2050 by 0.5°C as 

well as improve public health and food security.106 

The uncertainties cited by the EPA as a barrier to regulating climate impacts of aerosols 

do not apply to regulation of black carbon. Specific areas of uncertainty raised by the EPA are 

addressed below. 

Precise estimation of natural versus anthropogenic sources of aerosols and black carbon 

is not a prerequisite to regulation under the Clean Air Act. The Policy Assessment focuses on 

the difficulty of separating natural and anthropogenic sources of aerosols as a major obstacle to 

regulating the climate impacts of aerosols.107 This, however, is not a valid excuse for failing to 

address black carbon. Regardless of natural sources of black carbon, the data indicate that there 

are significant anthropogenic sources of black carbon that contribute a large proportion of total 

black carbon emissions.108 In addition, as the Clean Air Scientific Advisory Committee 

comments on the ISA indicate: “The EPA promulgates a health-based standard irrespective of 

the background concentration of particles and thus, the PRB [Policy Relevant Background] 

primarily has implications for implementation.”109 Furthermore, as acknowledged in the Policy 

Assessment, “attainability and technological feasibility are not relevant considerations in the 

promulgation of national ambient air quality standards.”110 

The magnitude of black carbon’s radiative forcing is likely to be larger than estimated in 

the Proposed Rule. Another uncertainty cited by the EPA is the radiative forcing of aerosols.111 

Again, there is enough information related to black carbon’s impact to know that global 

temperatures will rise due to black carbon emissions. As discussed above, there are varied 

estimates in the literature, but the radiative forcing used by the IPCC in the Fourth Assessment 

report and adopted by the EPA represents one of the lowest estimates in the literature. 

Subsequent studies suggest the radiative forcing is actually higher. The continually increasing 

 

103 Bond, Tami & Haolin Sun, Can Reducing Black Carbon Emissions Counteract Global Warming?, 39 Environ. 

Sci. Technol. 5921 (2005). 

104 Ramanathan and Xu 2010. 105 Jacobson 2010. 106 Shindell 2012. 107 USEPA, Policy Assessment for the Review of the Particulate Matter National Ambient Air Quality Standards 

(Apr. 2011) (“USEPA Policy Assessment”) at 5-12. 

108 See, e.g., UNEP SLP Report 2011 at 16-17 discussing sources and new studies and inventories since 2007. 109 USEPA, Comments from the Clean Air Scientific Committee (CASAC) to the Integrated Science Assessment for 

Particulate Matter (ISA) re Review of Integrated Science Assessment for Particulate Matter (Second External 

Review Draft of July 2009) (November 24, 2009) (“USEPA CASAC comments to ISA”) at 13. 

110 USEPA Policy Assessment at 1-3, quoting American Petroleum Institute v. Costle, 665 F. 2d at 1185. 111 Id. at 5-13 
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Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

estimates of black carbon’s forcing in the literature suggest that “uncertainty” in this case is 

equivalent to “underestimation.” 

Regional variability does not dilute the need for reductions in black carbon. Spatial and 

temporal heterogeneity of PM is cited within the Policy Assessment as confounding attempts to 

quantify regional climate responses.112 While it is certainly true that some regions may 

experience larger responses to black carbon than others, black carbon will exacerbate global 

warming wherever it occurs. This is similar to the case for any air pollutant. Some regions will 

benefit more from regulation than others, yet it remains a requirement of the Clean Air Act that 

air pollutants be limited to protect national health and welfare. 

 Black carbon’s negative climate impacts do not depend upon details of cloud interactions 

with aerosols. Aerosols undergo complex interactions with clouds, which in turn dictate how 

aerosols affect global temperatures. The details of these interactions have not yet been 

established. The Policy Assessment views this lack in detail as a barrier to modeling aerosol 

climate impacts and consequently addressing the effects.113 First, black carbon’s direct radiative 

forcing is not cloud-dependent. Second, a recent simulation by Jacobson that included cloud and 

precipitation interactions indicated that controlling fossil and solid-biofuel black carbon had the 

greatest potential to reduce Arctic temperature of any mitigation strategy.114 Third, Chung and 

Seinfeld estimate that positive and negative indirect effects related to cloud interactions cancel 

each other resulting in only a minor contribution to of carbonaceous aerosols from biomass.115 

 Reducing black carbon will undoubtedly benefit public health and welfare with regard to 

both visibility and climate. The EPA does not need to quantify the precise amount of climate 

benefit to know that component of PM2.5 must be controlled under the Clean Air Act. 

Furthermore, as summarized above and in numerous scientific and international reports, the EPA 

has abundant information on the best abatement options for black carbon. 

The courts have made clear that uncertainty does not absolve the EPA of the obligation to 

protect public welfare. In American Trucking Association, the Court stated that with regard to 

secondary NAAQS, the “EPA must act as soon as it has enough information (even if crude) to 

‘anticipate’ such effects.”116 Climate is one of the defined components of “public welfare” under 

the CAA.117 The EPA currently has enough information regarding the climate impacts of black 

carbon to trigger the duty to protect public welfare under section 109(b) of the CAA. There may 

be regional uncertainties in the magnitude of this effect, with some areas experiencing more 

warming than others. Overall, however, there is a substantial body of knowledge emphasizing 

the importance of black carbon as a climate forcer. 

III. THE PM2.5 NAAQS SHOULD BE REVISED TO SEPARATELY ADDRESS 

BLACK CARBON 

 

112 USEPA Policy Assessment at 5-12. 113 USEPA Policy Assessment at 5-13. 114 Jacobson 2010. 115 Chung and Seinfeld 2012 at 4. 116 American Trucking Associations, Inc. v. EPA, 283 F.3d 355, 380 (D.C. Cir. 2002). 117 42 U.S.C. § 7602(h). 
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Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

The current size-based particulate matter categorization is insufficient to fully protect 

health and welfare. In particular, the effects of black carbon will not be sufficiently ameliorated 

without an additional, specific limit on this component of PM2.5. One reason why black carbon 

must be regulated separately is that it constitutes a relatively small proportion of total PM2.5 such 

that implementation plans will likely focus on components that are a larger proportion of total 

PM2.5 mass. Although there are currently regulations in place to address some new sources of 

black carbon, setting a limit for black carbon within the PM2.5 NAAQS is urgently needed to 

address existing sources. 

Moreover, the black carbon component of PM2.5 has significant impacts on public 

health.118 These effects include cardiovascular, systemic vasculature, total mortality, and 

potentially respiratory impacts.119 Ultrafine black carbon also has been associated with cognitive 

impairment in children.120 When first emitted from fossil fuel combustion, black carbon is very 

small (diameter less than 0.1 μm) and occurs in the “ultrafine particle” size range.121 As an 

ultrafine particle, black carbon may have enhanced health effects because it can cross biological 

membranes.122 As they age, black carbon particles grow in size and continue to harm public 

health. Although other constituents have also been associated with adverse health outcomes, the 

data show that black carbon, especially from transportation sources, is one of the components of 

PM2.5 that is most harmful to public health. As discussed above, black carbon is also a strong 

climate forcer with impacts on public welfare. Among the climate impacts of black carbon, are 

public health harms that are separate from those traditionally associated with PM. All of the 

evidence supports an approach that sets a separate limit for black carbon in addition to an annual 

standard of 11 μg/m3 and a 24-hour standard to 25 μg/m3 for PM2.5. Such an approach is clearly 

needed in order to provide the required protection to both public health and welfare. 

A. The Current Size-Based Approach Will Not Adequately Address the Climate 

Impacts of Black Carbon 

The Policy Assessment acknowledges that the secondary NAAQS for PM 2.5 will not 

address climate impacts: 

The current standards that are defined in terms of aggregate size mass cannot be 

expected to appropriately target controls on components of fine and coarse 

particles that are related to climate forcing effects. Thus, the current mass-based 

PM2.5 and PM10 secondary standards are not an appropriate or effective means of 

focusing protection against PM-associated climate effects due to these differences 

in components.123

 

118 ISA chapter 6 and 7 (short- and long-term effects, respectively). 119 See ISA at 2-26. 120 See, e.g., Suglia, Franco et al., Association of Black Carbon with Cognition among Children in a Prospective 

Birth Cohort Study, 167 Amer. J. of Epidimiology 3 (2008). 

121 ISA at 155, 240. 122 See, e.g., ISA at 4-21. 123 USEPA Policy Assessment. 
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Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

The Policy Assessment then rejects a PM component-specific approach based on uncertainties in 

climate science. As discussed above, however, it is incorrect to conclude that black carbon 

climate science is so uncertain as to preclude such an approach. 

 Similarly, with regard to public health impacts, the Policy Assessment states: 

[W]e conclude that additional information available in this review continues to 

provide evidence that many different constituents of the fine particle mixture as 

well as groups of components associated with specific source categories of fine 

particles are linked to adverse health effects.124

The Policy Assessment rejects an approach that would set standards for PM components 

separately due to the fact that many components are associated with similar health outcomes. 

 The EPA considered that a constituent-specific approach to setting NAAQS could be 

superior to the current size-based approach.125 In commenting on the Integrated Science 

Assessment, the Clean Air Scientific Advisory Committee supported this approach for future 

revisions, and suggested this may be particularly important for carbon compounds.126 Black 

carbon must be regulated separately and in addition to PM2.5 because absent separate standards 

sulfates and nitrates may be more likely to be mitigated than the black carbon component of PM. 

B. Without a Speciation Approach, Reductions in Other Constituents of PM2.5 Are 

Likely To Be Prioritized Over Reductions in Black Carbon 

Black carbon is likely to receive less focus than other PM components when states are 

considering how to implement the PM2.5 NAAQS. Sulfates and nitrates are more likely to be the 

target for PM mitigation, in part because their precursors, SOx and NOx, are already subject to 

separate NAAQS. As explained in the recent EPA report to Congress regarding black carbon: 

In recent years, the overarching PM2.5 control program for stationary 

sources in the United States and Europe has focused mainly on secondarily 

formed particles such as sulfates and nitrates, rather than on direct PM2.5 

emissions. This is because PM controls motivated by public health and 

environmental goals are focused on reducing total PM mass (a large portion of 

which is sulfates and nitrates formed in the ambient air from SOx and NOx) at 

least cost. PM controls oriented toward climate would have to consider the light 

absorbing and scattering properties of the various PM constituents.127

In addition, the proposed visibility standard may inadvertently result in an added 

emphasis on sulfates. This fact was emphasized within the CASAC comments on the draft 

Policy Assessment: 

 

124 USEPA,Policy Assessment at 2-55. 125 Proposed rule at 38922 126 USEPA CASAC Comments to ISA at 2. 127 USEPA Black Carbon Report at 162. 
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Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

My major concern has to do with consideration for the potential of the tightening 

of the standards to exacerbate climate warming if the appropriate fraction of PM 

is not preferentially controlled....Decreasing light scattering aerosols will 

improve visibility, but increase radiative forcing. It would be better to focus on 

reducing light absorbing aerosols to both improve visibility and potentially reduce 

warming (there is uncertainty about the latter). There is also a growing body of 

evidence that EC [elemental carbon, i.e. black carbon] is more strongly associated 

with various health impacts, so in the implementation, focusing on EC controls 

would be a win-win.128

In low humidity conditions, black carbon is the largest contributor to low visibility.129 Thus, 

balanced reductions in sulfates and black carbon will improve visibility as well. Sulfate pollution 

has been decreasing and is expected to continue to do so over the next several decades.130 This 

trend will put greater importance on reducing short-lived climate pollutants such as black carbon. 

Finally, despite its significant impacts, black carbon is a relatively small proportion of the 

total volume of PM2.5 (approximately 10%).131 As a result, mitigation options that address 

larger-volume components of PM2.5 will probably be prioritized over black carbon reductions. 

C. Current On- and Non-Road Diesel Regulations Do Not Mitigate Existing 

Sources of Black Carbon 

 Black carbon must be regulated through the NAAQS program in order to address existing 

mobile sources of black carbon. The EPA currently regulates emissions from new heavy-duty 

diesel trucks, non-road diesel engines, locomotives, and marine engines. These programs are an 

important part of addressing black carbon. But it is important to note that these regulations apply 

only to new model years and are being phased in slowly. As a result, they will not yield 

significant reductions in black carbon until approximately 2030.132 The current regulations will 

not have significant impact until the national fleet has been fully replaced by new vehicles. The 

EPA’s Report to Congress on Black Carbon indicates that additional reductions in black carbon 

will not occur in the absence of further regulation.133 The NAAQS program is one of the few 

opportunities to reduce black carbon from existing engines, industrial and biofuel sources within 

the United States and rapidly reduce emissions of this pollutant. Time is of the essence: the 

Arctic ocean will likely be ice free in the summer by 2030 without immediate and significant 

reductions in black carbon combined with reductions in carbon dioxide, methane, and other 

greenhouse pollutants. 

 

128 U.S. Environmental Protection Agency, Comments from the Clean Air Scientific Committee (CASAC) to the 

Integrated Science Assessment for Particulate Matter (ISA) re Review of Policy Assessment for the Review of the 

PM NAAQS (Second External Review Draft of July 2010) (September 10, 2010). 129 ISA at 9-8. 130 See, e.g., UNEP SLP Report 2011at 13. 131 ISA at 3-59. 132 UNEP SLP Report 2011 at 12; USEPA Black Carbon Report at 175. 133 USEPA Black Carbon Report at 166. 
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Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

IV. THE PROPOSED PM NAAQS DO NOT REFLECT THE ADMINISTRATOR’S 

UNENCUMBERED ASSESSMENT OF THE LEVEL REQUIRED TO PROTECT 

PUBLIC HEALTH 

The Proposed Rule published in the Federal Register134 does not reflect the 

Administrator’s independent assessment of the PM2.5 limits required to protect public health. 

The Office of Management and Budget (“OMB”) reviewed a draft of the proposed rule prior to 

publication and suggested changes that weakened the proposed PM NAAQS.135 When the 

proposed rule was first circulated for interagency review, the primary NAAQS for PM2.5 would 

have been reduced from 15 to 12 μg/m3

. The OMB, however, returned the draft rule with a 

suggested range of 12 to 13 μg/m3.

136 This is how the published version of the proposed rule 

now reads.137 

In response to the OMB comments, language was deleted that stated: “In the 

Administrator’s judgment, an annual standard of 12 μg/m3

 reflects placing greatest weight on 

evidence of effects for which the Integrated Science Assessment has determined there is a causal 

or likely causal relationship with long- and short-term PM2.5 exposures.”138 The original draft 

proposed rule also explained why a standard set at 13 μg/m3 could not provide an adequate 

margin of safety: 

The Administrator recognizes that consideration for setting a higher 

annual standard level, e.g., up to 13 μg/m3

, would reflect an approach that places 

significantly less emphasis on margin of safety considerations than a standard set 

at 12 μg/m3. It would also reflect placing essentially no weight on more limited 

evidence of serious effects in susceptible populations (e.g., infant mortality, low 

birth weight) and would likewise place essentially no weight on additional 

population-level data from a limited number of epidemiological studies. In 

addition, this approach would require the Administrator to explain why a standard 

established above the level of the long-term mean PM2.5 concentrations reported 

in several robust well-conducted studies, notably the Burnett et al. (2004) and Bell 

et al. (2008) studies, would provide requisite protection with an adequate margin 

of safety. The Administrator is not presently aware of any such explanations.139

This explanation was also deleted in the published version of the rule. 

These last-minute edits made to the proposed rule are contrary to the statutory 

requirement that the Administrator use her best judgment to determine what limit on criteria air 

pollutants is required to protect public health and welfare. Under section 108 of the Clean Air 

 

134 77 Fed. Reg. 38890. 135 Eilperin, Juliet, White House Weakened EPA Soot Proposal, Documents Show, The Washington Post (July 17, 

2012). 

136 Office of Management and Budget, Summary of Additional Interagency Comments Under Eos 12866 and 13563 

Regarding the NAAQS for Particulate Matter Proposed Rule: RIN 2060-AO47 (June 14, 2012). 

137 77 Fed. Reg. 38890. 138 USEPA, Redline Revisions sent by EPA to OMB on the Administrator’s proposed conclusions on the primary 

PM2.5 Standard levels (subsection III.E.R.e) (June 8, 2012). 

139 Id. at 49 (Internal citation omitted). 
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Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

Act, air quality criteria are intended to “accurately reflect the latest scientific knowledge useful 

in indicating the kind and extent of all identifiable effects on public health or welfare which may 

be expected from the presence of [a] pollutant in the ambient air.”140 In turn, section 109 requires 

the Administrator to promulgate primary and secondary NAAQS that are based on air quality 

criteria and in her judgment are requisite to protect public health and welfare.141 The 

Administrator made a judgment that the limit that would be based on air quality criteria and 

necessary to protect public health would need to be below 13 μg/m3

. The OMB has not been 

tasked with setting these standards and does not possess the expertise to assess what standards 

are necessary. Therefore, the OMB revisions are outside the law. 

V. EPA’S PROPOSED “GRANDFATHERING” PROVISION FOR PSD PERMITS IS 

UNLAWFUL 

The EPA proposes a “grandfathering” provision that would allow pending PSD permit 

applications already released for public comment as of the effective date of the revised NAAQS 

to be evaluated under the NAAQS that existed on the date public notice was given of the draft 

permit.142 This provision is not only contrary to “[l]ongstanding EPA policy” and regulation, as 

EPA concedes143, but also contrary to the statute. Even if the EPA had discretion to “balance” 

various policy considerations in implementing the PSD program—which, as described below, it 

does not—the agency has not justified its choice of an approach that sacrifices both air quality 

protection and meaningful public involvement to the convenience of permit applicants. The 

proposed “grandfathering” provision is unlawful, arbitrary and capricious. 

A. The Proposed Grandfathering Provision Exceeds EPA’s Statutory Authority 

Congress has spoken directly to the precise question at issue here, leaving the EPA 

without discretion to find some other way of interpreting the statute.144 

The EPA purportedly finds “discretion” to grandfather pending PSD permits in Section 

165(a), Section 165(c), and Section 301. Proposed Rule at 39,024/1. These provisions, 

however, confer no such discretion; on the contrary, Section 165(a) forecloses EPA’s approach. 

Under Section 165(a)(3), no major emitting facility “may be constructed” unless the facility’s 

owner or operator demonstrates emissions from the facility will not cause or contribute to the 

violation of “any . . . national ambient air quality standard in any air quality control region.” 42 

U.S.C. § 7475(a)(3)(B). Under the statute’s plain language, this requirement applies to the 

commencement of construction—not to some earlier “milestone” in the permitting process. This 

language also plainly prohibits construction of a facility that will violate “any” NAAQS—

meaning the EPA cannot pick and choose which NAAQS it will allow a particular facility to 

violate. Yet EPA’s grandfathering proposal would allow PSD permits to issue in violation of 

Section 165(a)(3). Overall, the Proposed Rule would tighten the PM NAAQS in certain respects. 

Accordingly, by allowing permitting authorities to review pending PSD permits under the prior, 

 

140 42 U.S.C. § 7408(b). 141 42 U.S.C. § 7409(b)(1) and (2). 142 Proposed Rule at 39,024/2. 143 Id. at 39,023/3. 144 See Chevron v. Natural Resources Defense Council, Inc., 467 U.S. 837 (1984) 
August 31, 2012 Page 21 of 29 

Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

less stringent NAAQS even after the new NAAQS goes into effect, the EPA’s proposal would 

authorize construction of facilities that cause or contribute to NAAQS violations. This is exactly 

what Section 165(a)(3) prohibits. 

Nothing in Section 165(c) provides the EPA with discretion to violate the plain language 

of Section 165(a). Section 165(c) merely states that PSD permits “shall be granted or denied” 

within one year of filing of the application. 42 U.S.C. § 7475(c). Nothing in this provision, 

however, authorizes the EPA to meet this deadline by granting a permit that does not meet the 

statute’s other mandatory requirements. Indeed, if the EPA cannot grant a permit within one 

year—consistent with all other permit requirements—it can comply with Section 165(c) by 

denying the permit. 

Nor does Section 301 confer discretion to avoid the requirements of Section 165(a)(3). 

Section 301 states only that “[t]he Administrator is authorized to prescribe such regulations as 

are necessary to carry out [her] functions under this chapter.” 42 U.S.C. § 7601(a)(1). The 

EPA’s regulatory authority thus extends no further than necessary to implement “this chapter”; 

in other words, the EPA’s regulatory authority is coextensive with the Clean Air Act itself. 

Section 301 in no way provides authority to regulate in a manner contrary to the plain 

requirements of “this chapter.” 

Although the Proposed Rule does not say so outright, the EPA seems to imply that there 

is some kind of conflict between the requirements of Section 165(a) and the deadline for 

issuance of permits in Section 165(c).145 There is no such conflict. The EPA does not claim, or 

even suggest, that implementation of the new NAAQS would make timely issuance of PSD 

permits impossible. Even if this were the case, the EPA could still implement both Section 165 

(a) and (c) according to each provision’s plain language by denying permits that cannot 

demonstrate compliance with applicable law within a year of application completeness. Statutes 

must be construed so as to give effect to all of their provisions. Hibbs v. Winn, 542 U.S. 88, 101 

(2004). As there is no statutory contradiction for the EPA to resolve, there is no need for the 

EPA to invoke the general regulatory authority of Section 301.146 In any event, any particular 

failure to comply with the deadline in Section 165(c) would not excuse the EPA’s duty to 

comply with the Act’s other requirements. Cf. General Motors Corp. v. United States, 496 U.S. 

530, 540-42 (1990). 

The EPA also claims Section 160(3) “call[s] for a balancing of economic growth and 

protection of air quality.” Proposed Rule at 39,024/1. Nothing in Section 160(3) allows the 

agency to “balance” away clear and mandatory requirements of the statute. This section states 

only that one purpose of the PSD program is to “insure [sic] that economic growth will occur in a 

manner consistent with preservation of existing clean air resources.” 42 U.S.C. § 7470(3). The 

EPA’s “grandfathering” proposal directly contradicts this purpose by allowing economic growth 

(i.e., construction of major facilities) in a manner inconsistent with preservation of clean air 

 

145 To the extent EPA is relying on such an implied “conflict,” it has failed to adequately explain the rationale for its 

proposal. 

146 Cases such as Citizens to Save Spencer County v. EPA, 600 F.2d 844 (D.C. Cir. 1979), which upheld EPA’s 

attempt to fashion a regulatory compromise where two statutory provisions were in direct and irreconcilable 

conflict, are thus inapposite here. 
August 31, 2012 Page 22 of 29 

Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

resources (i.e., in violation of a NAAQS adopted to protect health and welfare). The EPA’s 

purported “balancing” is merely the substitution of a policy preference for a statutory 

requirement. New York v. EPA, 443 F.3d 880, 889 (D.C. Cir. 2006) (“EPA may not ‘avoid the 

Congressional intent clearly expressed in the text simply by asserting that its preferred approach 

would be better policy.’”) (quoting Engine Mfrs. Ass’n v. EPA, 88 F.3d 1075, 1089 (D.C. Cir. 

1996)). EPA’s “balancing” act is plainly unlawful. 

The EPA further claims that it may exempt facilities from the new PM NAAQS because 

it has adopted similar provisions in the past. Proposed Rule at 39,023/3. None of the cited 

rulemakings provides or identifies legally adequate authority for the exemption the EPA 

proposes here. Indeed, in its 1980 final rule revising the PSD regulations, the EPA explicitly 

rejected a “grandfather” provision based on the date of application completeness rather than the 

date of permit issuance, citing concerns that the broader exemption would fail to protect air 

quality—a core goal of Section 165. 45 Fed. Reg. at 52,683 (Aug. 7, 1980). In any event, 

“previous statutory violations cannot excuse the one now before the court.” New Jersey v. EPA, 

517 F.3d 574, 583 (D.C. Cir. 2008). 

The Clean Air Act as a whole further confirms the EPA has no general warrant to create 

new “grandfathering” exemptions. Congress has adopted only one express provision allowing 

“grandfathering” under the PSD program. See 42 U.S.C. § 7478(b). It has not created or 

authorized other such exemptions. Where Congress has provided express exemptions, but has 

not enacted others, the EPA is not free to create additional, unauthorized exemptions from 

applicable statutory requirements. See Andrus v. Glover Constr. Co., 446 U.S. 608, 616-17 

(1980). 

Finally, the EPA’s rationale for choosing the release of a draft permit for public comment 

as the “milestone” triggering the grandfathering provision is also contrary to statute. The EPA 

claims the application of new NAAQS requirements after the public comment period has begun 

“would unduly delay the processing of the permit application by potentially requiring an 

additional public comment period and additional work by the reviewing authority at a time when 

it should be focused on considering public comments and preparing a final permit decision . . . .” 

Proposed Rule at 39,024/2. Section 165 prohibits construction of a major facility in an area to 

which PSD requirements apply unless “interested persons” have been provided an opportunity 

“to appear and submit written or oral presentations on the air quality impact of such source, 

alternatives thereto, control technology requirements, and other appropriate considerations.” 42 

U.S.C. § 7475(a)(2). By “grandfathering” facilities as of the date a draft permit is released for 

comment, the EPA’s proposal deprives interested persons of their statutory right to comment on 

air quality impacts, alternatives, control technology, and other considerations related to the 

current NAAQS. 

The Proposed Rule’s complaints about “delay” and “additional work” also betray a 

disturbingly cavalier attitude toward public comment. Under the EPA’s existing regulations, 

public comments may raise “substantial new questions” requiring revisions to a draft permit and 

reopening of the public comment period. 40 C.F.R. § 124.14(b). Accordingly, the EPA’s own 

regulations already anticipate some “additional work” and “delay” after the release of a permit 

for comment are anticipated by EPA’s regulations. Indeed, without the possibility of revisions in 
August 31, 2012 Page 23 of 29 

Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

light of public comments, public comments would be largely meaningless. The EPA’s proposal 

to foreclose public comments on compliance with the NAAQS in the name of avoiding delay and 

additional work—while its own regulations expressly anticipate the potential for both delay and 

additional work on all other aspects of a draft permit—is entirely arbitrary. 

In short, EPA’s “grandfathering” proposal is contrary to the Clean Air Act. EPA cannot 

lawfully finalize this proposal. 

B. EPA Has Not Justified the “Balance” Struck by the Proposed 

Grandfathering Provision 

Even if the Clean Air Act were ambiguous or silent as to the EPA’s “grandfathering” 

authority—which, as demonstrated above, it is not—the Proposed Rule would still represent an 

impermissible construction of the statute. See Chevron, 467 U.S. at 843. Exempting facilities 

from the revised NAAQS solely because draft permits have been issued is incompatible with the 

statute’s purpose and structure. 

The EPA claims broad authority to “balance” economic growth and air quality protection. 

As discussed above, the EPA has no such authority, but even if it did, the agency would have to 

exercise that authority in light of the purposes of the Clean Air Act. Those purposes 

overwhelmingly favor protection of air quality, health, and welfare; to the extent the Act 

mentions maintenance of productive capacity and economic growth, it does so in the context of 

requiring advancement of those values in a manner that preserves clean air. See, e.g., 42 U.S.C. 

§§ 7401(b), (c); 7409(b); 7470. Indeed, when setting a NAAQS—as the EPA proposes to do 

here—the EPA cannot factor in cost considerations at all. Whitman v. Am. Trucking Ass’ns, 531 

U.S. 457, 471 (2001). The Clean Air Act strikes a balance that strongly favors protection of 

public health and air quality over economic factors. 

The EPA’s “grandfathering” proposal, in contrast, strikes the opposite balance. It would 

allow issuance of permits that violate applicable NAAQS standards. The standards that will be 

violated, of course, are by definition those “requisite” to protect health and welfare. 42 U.S.C. § 

7409(b)(1), (2). The EPA’s proposal thus sacrifices the Act’s core purposes to economic 

considerations the agency has not even bothered to identify with any particularity. This is not a 

“balancing” act the statute will bear. 

The EPA does not even fully explain why it chose to unbalance the Act’s purposes in this 

way. The Proposed Rule makes no attempt to define what permitting delays the EPA would 

consider “unreasonable”; indeed, it appears that the EPA regards any delay as unreasonable, 

regardless of the impact on air quality, public health, and welfare, and even if the permit still 

could be issued within one year of application completeness. Nor has the EPA adequately 

explained what factors the agency considered in developing the proposal; aside from a 

conclusory paragraph or two about the “delay” and “extra work” occasioned by permit revisions 

following release for public comment, the EPA has not identified with any precision the 

competing considerations it proposes to “balance” or how its proposal achieves its goals. 
August 31, 2012 Page 24 of 29 

Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

Instead, the EPA appeals to “basic principles of fairness and equity.” Proposed Rule at 

39,024/1. In so doing, the EPA misunderstands the scope of its authority as an administrative 

agency. Powers of equity are normally exercised by courts, not administrative agencies; unlike 

courts, agencies have “no constitutional or common law existence or authority,” and thus 

exercise only the authority conferred by Congress. Michigan v. EPA, 268 F.3d 1075, 1081 (D.C. 

Cir. 2001) (“If there is no statute conferring authority, a federal agency has none.”). Nothing in 

the NAAQS or PSD programs confers equitable powers on the EPA; accordingly, the EPA does 

not have those powers. Indeed, the D.C. Circuit Court of Appeals has struck down EPA rules 

that were intended in part to achieve the agency’s goals of equity and fairness, but were 

nonetheless in excess of its statutory authority. See N. Carolina v. EPA, 531 F.3d 896, 918, 921, 

reh’g granted in part on other grounds, 550 F.3d 1176 (D.C. Cir. 2008). Again, fairness is a 

noble goal, but EPA’s extra-statutory notion that prioritizing the convenience of polluters over 

the health of the public promotes fairness and equity cannot justify deviations from statutory 

command. 

The EPA’s “grandfathering” proposal is an impermissible construction of the Clean Air 

Act that runs counter to the statute’s purpose and exceeds the agency’s prerogatives. It cannot 

lawfully be adopted in the final NAAQS. 

VI. CONCLUSION 

This rulemaking presents a critical opportunity to provide substantial direct public health 

benefits while mitigating short-term climate impacts. It is essential that the EPA promulgate air 

quality standards that protect both against the direct health impacts of PM2.5 inhalation, as well as 

against dangerous climate change by providing a separate limit for black carbon, in addition to 

an annual standard of 11 μg/m3 and a 24-hour standard to 25 μg/m3 for PM2.5. This would 

achieve a balanced reduction in warming and cooling components and improve public health and 

welfare. The science related to black carbon is well-developed and establishes the importance of 

reductions in this short-lived climate pollutant. In addition, the proposal to “grandfather” in 

pending PSD permit applications already released for public comment is unlawful. Finally, it is 

essential that the EPA establish a better monitoring network to measure individual ultrafine and 

fine PM components. Thank you for the opportunity to comment. If you have any questions 

about this letter or the references attached, please contact Andrea Weber at (415) 436-9682 

x.311, or aweber@biologicaldiversity.org. 

Sincerely, 

Anna Moritz 

Legal Fellow, Center for Biological Diversity 

Enc: References cited and attached 
August 31, 2012 Page 25 of 29 

Center for Biological Diversity Comments on Proposed PM NAAQS, 77 Fed. Reg. 38890 

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