From: "Frey, Nathan J." <Nathan_J._Frey@omb.eop.gov>

To: Lydia Wegman/RTP/USEPA/US@EPA Date: 06/06/2012 08:00 AM Subject: Summary of Interagency Comments Under EO 12866/13563: National Ambient Air Quality

Standards for Particulate Matter NPRM

Attached please find a summary of interagency comments under EO 12866/13563 on the EPA proposed rule regarding National Ambient Air Quality Standards for Particulate Matter: RIN 2060

- AO47.

Thank you and please let me know if you have any questions.

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review.
General Comments 1) Attainment and Monitoring EPA proposes to eliminate spatial averaging and "population

- oriented" monitor placement, while mandating a near

- road component to monitoring plans. Some c ommenters believe that these three provisions are internally inconsistent. Spatial averaging is a statistical means of expressing the 'ambient' aspect of "National Ambient Air Quality Standards." Averaging over the regulated area creates the regulatory consistency for the regional jurisdictions that is key to the regionally

controlled implementation of the NAAQS. EPA cites the possibility of disparate health effects on disadvantaged populations as the reason for eliminating averaging. However, EPA also proposes to eliminate "population

- oriented" monito r placement, since EPA says that the concept of a monitor being population

- oriented is incompatible with the 'ambient' nature of the NAAQS. In this provision, EPA dismisses linking NAAQS attainment to health effects as inconsistent with statute, even thou gh the touchstone of the NAAQS standards is in fact public health. 2) Some commenters believe that EPA's reasoning for a near

- road component to monitoring plans is inconsistent with its reasoning above. Near

- road PM levels are not necessarily representative of actual risk to susceptible populations through exposure to PM. Nor is the placement of near

- road monitors calculated to be a better proxy for health effects than "population

- oriented" monitors. The elimination of spatial averaging and "population

- ori ented" monitors and the establishment of near

- road monitors can only have the effect of making NAAQS attainment more difficult. 3) Some commenters also note that the proposed PM standards and their impacts appear to be based on existing monitoring systems, such that the addition of near

road monitors can increase the costs by putting additional areas into nonattainment without associated health benefits. 4) Some commenters note that a ny difficulties in achieving attainment will likely translate into difficulti es in PSD permitting. The elimination of spatial averaging, along with the inclusion of near

- road monitors, is likely to make it more difficult to obtain permits. These c ommenters note that where EPA changes its interpretation about 'exclusion of some re ceptors' in PSD analyses, it does account for these changes and suggest that EPA clearly identify how these changes may or may not affect permitting decisions.

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review.

5) Communication of Public Health Information (Pages 218

- 225) from EO12866_PM_NAAQS_2060AO47_NPRM_Preamble_and_Reg_Text_20120529 Some commenters have concerns about the inclusion of the Air Quality Index (AQI) for PM2.5 into the NAAQS proposal at both ends of the index value spectrum. The re are concerns that the upper le vels of the AQI (200

- 500 index value) being proposed are not scientifically justified and will potentially have subs tantial agency resource impacts. Specific implications include large increases in wildfire suppression costs and decrease needed decision c apability on wildfires. The proposed potential deviation from defining the 100 index value at the 24hr NAAQS will lead to the development of a presumptive standard and will potentially further hinder critical prescribed fire operations. As this section (p p. 218

- 225) is not a requirement of the NAAQS, and therefore not part of the court mandated material, commenters recommend that it does not need to be part of this proposal. These c ommenters strongly recommend the removal of this section to allow for need ed discussion and development of a sound and interagency supportable proposal for the AQI for PM2.5. Accompanying this specific comment and several comments below are a ttached suggest ed edits regarding the relevant section of the preamble

. 6) A critical and ecologically indispensable method of addressing hazardous fuels across Federal lands is the use of prescribed fire. Managers conduct burns routinely up to the NAAQS 24hr standard level. Commenters express concerns that t he public perception of the AQI b eing “unhealthy for sensitive groups” at a lower value than the NAAQS may lead to further challenges to conducting these burns in a safe, economically efficient and prudent fashion. Commenters express concern that a sub

- NAAQS level may lead to a functiona l standard in application by air quality regulatory agencies. This creates a public perception that would pit beneficial and ecologically necessary prescribed fire and fuel mitigation measures against local air quality objectives and messages. Less pres cribed fire may negate the air quality benefits of judicious prescribed fire application as compared to vast PM2.5 and green house gas emissions from catastrophic wildfire. Commenters a lso note that smaller prescribed fires necessitated by such a presumpt ive standard can lead to higher risk to firefighters and substantial cost increases , which may also pose further challenges to wildland

- urban interf ace hazardous fuels treatments. 7) The reduction in upper thresholds of the AQI (200

- 500 index value) do not appear to be well supported by the 1952 based science provided in the proposal. In addition, the public perception of wildfire response decisions which result in extended periods of “hazardous” air quality may lead to additional pressure for

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review. suppression with its attendant costs as well as risks to firefighters. Wildfires can create high levels of PM2.5 that can be well above the proposed upper threshold for the AQI for significant periods of time. Assessment of the AQS as well as other monitoring networ ks show wildfire as the most common cause of high PM2.5 level at the AQI of threshold of “hazardous” as proposed . Commenters express concern that a public expectation for response could result when levels reach “hazardous” by all public agencies involved. Expectations and role for the federal agency wildland fire programs and wildland fire incident management teams are not well defined in this rulemaking package but can be significant. Commenters note that t he science for such response needs to be suppor ted and developed and further discussion of the AQI thresholds could provide the opportunity for efficient and cohesive planning for such impacts. 8) Some commenters express concerns that t he data used to propose the threshold for “hazardous” AQI values is not current. Commenters suggest that further work should be conducted to set this threshold. The technical basis for the pr oposed values is based upon outdated data from British coal combustion and secondary sulfate pollutions and is not related to wil dfire (biomass combustion) which would be the likely cause of contemporary high AQI values. With the public expectations and potentially large costs associated with setting and responding to a trigger such as “hazardous” air quality, a scientifically rigor ous approach that considers the likely causes of such an event in the US and one that uses national data is needed rather than a sub

- regional data analysis process. The balance of PM2.5 and PM10 contribution from the likely triggering sources in the US sho uld be considered in the analysis. Development of the upper AQI values can be implemented with good interagency coordination and with consideration of current technical capability. 9) A Statistical Test for Translating Evidence Into PM Standards: A commenter has suggested consideration of the following methodology for EPA to consider in setting the PM standard. In the studies in which EPA has determined they have confidence (those with “causal or likely causal relationships”), EPA states that the statistical relationship between dose and response can best be described by a linear equation (which is significantly different from zero, statistically). However, this linear approximation of the true underlying relationship is only valid over the actual values of PM levels observed in the study

– there is no evidence that the relationship will remain linear at PM levels lower than those observed. This fact can be used to construct a statistical test to determine the lowest PM level at which there is sti ll evidence that the linear dose

- response relationship is significantly different from zero. EPA could then consider, subject to the authorities under the

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review.
Act, set ting the PM standard at the average of the results of this test for the studies in which EPA has confidence. After sorting the data of a given study by PM level, if the data point with the highest PM level is excluded, the sample mean of PM levels will be slightly lower. EPA can test this subsample to see if it still supports the hypothesis of a linear dose

- response level different from zero (technically speaking, to see if the null hypothesis of a relationship equal to zero is rejected). If so, EPA could then exclude the next highest data point and repeat the test, and so on until the null hyp othesis cannot be rejected. Retain the sample mean of the last subsample to reject the null hypothesis, and collect the results of similar tests for all studies that found a linear relationship significantly different from zero. Averaging all of these re sults can be used to inform the PM standard. 10) Health Effects of PM vs. Ozone: For epidemiological studies that explicitly test for the health effects of PM vs ozone and other pollutants, are the dose

- response relationships for PM weaker than those that tes t for the health effects of PM only? If so, has EPA given more weight to these studies in setting the standard? 11) Extrapolated Costs: Could EPA please put a spreadsheet in the docket with PM2.5 emissions by subsector (we’re most interested in the EGU, non

- E GU point sources, area sources, onroad, nonroad, and alm subsectors) for each county that is found not in attainment in 2020 after all known technologies have been implemented? If such a document is already in the docket, please provide its document numbe r. 12) Some c ommenters urge EPA to include in the preamble for the rule its view on the limitations and uncertainties in the currently available evidence that relate to association of distinct components of PM2.5 with different health endpoints. Commenters also request that EPA seek comment on those limitations and uncertainties. 13) Commenters propose a single paragraph to be added to the Preamble section entitled “Limitations and Uncertainties of Currently Available Evidence” on pages 63

- 64. The suggested in serted text for consideration is presented here in context with the paragraphs that would be before and after the text: [Existing text] In addition, where PM2.5 and other pollutants (e.g., ozone, nitrogen dioxide, and carbon monoxide) are correlated, it c an be difficult to distinguish the effects of the various pollutants in the ambient mixture (i.e., co

- pollutant

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review. confounding). Although many recent U.S. multi

- city studies did not analyze multipollutant models, evidence from single

- city studies available i n the last review suggest that gaseous copollutants do not confound the PM2.5

- related mortality association (US EPA, 2004, section 8.4.3.3) which is further supported by studies that examined the PM10

- mortality relationship (US EPA, 2009a, p. 6

- 182 and 6

- 2 01). [Text proposed for insertion] Similarly, EPA has not found evidence that distinct components of PM2.5 differentially affect specific health endpoints. Although EPA has not applied the criteria in Table 1

- 2 of the Integrated Science Assessment to i ndividual species of PM2.5, the currently available evidence does not appear to support an attribution of health effects to black carbon that can be distinguished from other components of PM2.5. Because scientific understanding of this issue continues to evolve, specifically with regard to the toxicity of black carbon (and potentially other PM2.5 components) relative to other species of PM2.5, EPA seeks comments on whether or how uncertainties related to attribution of health effects to specific components of PM2.5 could be addressed. [Existing text] While uncertainties and limitations still remain in the available health effects evidence, the Administrator judges the currently available scientific data base to be stronger and more consistent than in previ ous reviews providing a strong basis for decision making in this review. Specific comments regarding the Primary Standard 14) Suggest explaining more clearly why a risk assessment was not used for recommending a specific level of the standard (beyond supportin g the conclusion that the annual standard should be controlling) 15) Suggest providing a more clear explanation for why “the number of participants within each study area can be used as a surrogate for health event data in relation to the distribution of PM2. 5 concentrations” for considering the 25th and 10th percentiles. 16) Throughout (and drawing on language from CASAC, perhaps?), the preamble references “the broader range of PM2.5 concentrations that were most influential in generating health effect estimates in epidemiological studies” (see p. 46). Suggest providing a more clear explanation of what is meant by “most influential,” as this will likely be confusing for many readers.

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review. 17) Pg. 49 describes a number of uncertainties that relate to staff recommendation s about the level of the standard. Shouldn’t one of the uncertainties (referenced here and perhaps elsewhere) be limited data on health effects at lower concentrations? 18) Suggest incorporating a more expanded discussion of the work that was done in response to CASAC and public comments on the Second Draft Policy Assessment (perhaps drawing from the cover letter for the Final PA). 19) Suggest that EPA more explicitly describe how the Administrations proposed conclusions on the primary standards (p. 143) address requisite protection for especially suscep tible or vulnerable populations. 20) Relevant to figure 4: Given that this is a critical figure for understanding the Policy Assessment’s and the Administrator’s reasoning for selecting the proposed level of the standard, some commenters suggest providing a more consolidated explanation of how the chart should be interpreted. That would likely require recapping information already discussed at greater length elsewhere, but would focus on how the chart itself should be understood. Specifically, it is not immediately clear what “mean” the diamonds, triangles, and s quares represent (in fact, this is simply the mean observed PM levels from the relevant studies). As a result, the casual (or even non

- casual) reader could easily assume that, because the bulk of the points here are between 13 and 15, the evidence points to the “right number” (perhaps the minimum level at which an effect was found) being within this range. It should be made very clear what these points do and don’t represent.
Commenters strongly suggest making more clear (in both the figure itself and th e description of the figure) that the 25th and 10th percentile bars displayed here are based on health event data (or proxies for health event data). This is not clear, particularly given that the long

- term means displayed here (if understood correctly) a re actually from a different distribution

– they are means of the observed air quality and do not specifically represent a range of observed health events/effects. If the diamonds, triangles, and squares do represent the 50th percentile of air quality rat her than the 50th percentile of health outcome, then the rationale for doing so should be explained more clearly in the text. Specifically, the text seems to hint that the reason for examining the distribution is that there is less confidence in results a t health levels for which data are more sparse. If so, it would seem that the

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review. relevant 50th percentile should be for health, not for ambient pollution. If there is an accepted peer

- reviewed method that links “confidence” in results to density of data point s that would support EPA’s approach, that should also be referenced. If not, EPA should state that their approach is based on heuristics. EPA may also wish to consider replacing the shapes with 50th percentile health effects. EPA should consider placing asterisks next to the studies that are relevant for susceptible and vulnerable populations. 21) In a number of places, the preamble states that the Administrator “provisionally concludes” some matter regarding the NAAQS revision. Appreciating that EPA may be using this term to signal that the Administrator has not yet made her final decision ; however, a commenter felt that the term “provisionally concludes” seem ed odd, as if there is some further action or specific information upon which the Administrator’s fi nal decision will depend. EPA should consider using the phrase: “proposes to conclude” . Specific Comments regarding the Secondary Standard 22) Some commenters request clarification regarding welcome why EPA believes that it must revise the secondary PM sta ndard. Commenters note that EPA does not have estimates of the costs and benefits such a revision adds to the rule, and as such has a limited justification that the preferred standard is 'requisite to protect public welfare.' Commenters also express conc ern a bout EPA's reliance on a willingness

to
- pay methodology as the basis for its future benefits estimate , expressing doubt that the methodological problems inherent in WTP can be adequately addressed and resolved in the short timetable for interagency re view. Finally, several commenters expressed significant concern that EPA is moving forward with a secondary standard based on an indicator, in light of CASAC’s statement in their review of the Second External Review Draft Policy Assessment , that “Overwhelmingly, CASAC would prefer the direct measurement of light extinction, the property of the atmosphere that most directly relates to visibility effects.” Furthermore, several commenters expressed similar concerns regarding EPA’s considerati on, recommended by CASAC, of the potential radiative forcing impacts aerosol reductions. 23) Some commenters suggest that EPA should request comment whether it should move forward with the primary and secondary standards on the same timeline and on whether th e designations must move forward in tandem. This is especially important given how different the visibility measure is from previous efforts and

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review. given that major rules affecting PM (GHG mobile sources and Boiler MACT) are not included in the baseline anal ysis and the significant work required in some states to comply with CSAPR

- better

- than

- BART or state

- specific consent decrees. 24) Some commenters recommend that EPA should signal maximum flexibility in its enforcement of CAA timelines. For example, EPA has discretion to provide up to 2 1

- year extensions on secondary standards. Given the nature of this new requirement and the modeling difficulties that EPA acknowledges, EPA should indicate willingness to grant these extensions. 25) Under 40 CFR 52.21(o) and ( p), visibility analyses are routinely conducted as part of the PSD process. Commenters express concern regarding the potential creation of a different set of analytical requirements for the PM2.5 visibility index that may create "competing" techniques for visibility assessment between the proposed PM2.5 visibility index and Class I procedures which could undermine existing processes and requirements used to protect visibility in Class I wilderness areas. 26) Some commenters suggest that the Agency remove the language describing a paucity of supporting speciation data. This language could be construed such that the current methods used for visibility assessment for Class I analyses are not adequate, and that EPA is instead proposing to use a simple surrogacy technique. The implications of this could weaken the technical credibility of the tools used for Class I visibility assessments under 40 CFR 52.21(p) or the Class II visibility assessments under the Additional Impact Analysis ( 40 CFR 52.21(o)) of the PSD rule. Moreover, at 70 FR 39121 EPA identified the CALPUFF system as "the best currently available tool for analyzing the visiblity effects of individual sources." These commenters request ed clarification upon why the methods that have been ro utinely used for visibility assessment under the PSD program are not deemed applicable to the prop osed PM2.5 visibility index. 27) Preferred Form of IMPROVE Algorithm Some commenters express specific concerns regarding the d iscussion starting on page 239 o f NPRM_Preamb le_and_Reg_Text and note that it is important that the “revised” form of the IMPROVE equation (split

- component mass extinction efficiency) be presented as the preferred algorithm. Commenters express concern that t o do otherwise undermines the robust science and modeling procedures inherent in the Regional Haze Rule and under the PSD program. Adopting the old form of the IMPROVE equation would, in essence, create additional, sometimes competing analytical requireme nts in the major source permitting process if

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review. permitting procedures must be enacted for comparison against the secondary PM2.5 standard. 28) Some commenters note practical difficulties associated with the implementation of a sub

- daily visibility NAAQS , which would require application of historical averages of speciation profiles from the closest STN monitoring site and require application of same day hourly relative humidity values. 29) Some commenters also note difficulties associated with using historical mon thly or seasonal speciation averages or estimates as surrogates for calculating light extinction for consideration of use with either continuous FEM or gravimetric FRM PM2.5 mass samplers. 30) Please clarify what background visual range would be used to compa re light extinction against if this proposal is simply based upon absolute deciviews. This is an important implementation aspect of this proposed rule which should be aligned with the components of the Regional Haze Rule which requires current visual air quality to be compared to "natural background" in order to determine progress towards the RHR goals. 31) Some commenters strongly support the use of the climatological relative humidity values based upon either the 2003 EPA guidance or similar guidance (e. g. FLAG 2010). Normalization of RH values through the use of climatic means is an efficient means to avoid justifying exclusion of certain hours based upon the presence of weather events. This could occur if air quality modeling is required for the second ary NAAQS under the PSD program. 32) The description of the policy assessment states that “...the Policy Assessment notes that this scatter could be reduced by the use of same

- day hourly relative humidity data to calculate a 24

- hour average value of the relati ve humidity term in the IMPROVE algorithm.” Commenters request c larification of this concept noting that t he 24

- hour average f(RH) is not the same as calculating a 24

- hour average relative humidity and applying it to the f(RH). Calculating 24

- hour f(RH) (with hourly RH values capped at 95%) is the appropriate procedure if this were to be followed. 33) Some commenters do not support alternatives that cap relative humidities at 90 percent. The approach described for the policy assessment of capping at 95% is the most appropriate and is consistent with FLAG guidance.

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review. 34) The preamble should discuss whether it is premature to establish a new secondary standard when there is not a suitable indicator and the scientific support underlying the standard is so uncertain . The preamble should also note that the Agency will continue to develop methods for an indicator and seek to reduce the uncertainty in the scientific literature before the next review. A commenter also suggested the proposal could seek comment on settin g the secondary standard equal to the primary standard. 35) As the preamble notes, CASAC overwhelmingly recommended using a direct measurement of light extinction as the indicator for the secondary standard. The preamble states that the Administrator concurs

. 36) Given that CASAC suggested the indicator approach would best be considered an interim approach, p lease indicate in the preamble how long it would take to finalize an FRM for direct measurement of light extinction. What steps are necessary to complete this process? 37) On pg 280. what does it mean that the Administrator “provisionally” concludes a new calculated light extinction indicator is appropriate? Please clarify whether the calculated light extinction indicator is merely an interim indicator until a direct measureme nt indicator can be established. If this is an interim indicator, specifically what steps does EPA plan to take to replace the index with a direct measurement approach? 38) Please indicate how difficult and expensive it would be for delegated authorities to implement a new secondary standard, recognizing that it will require new tracking systems, recordkeeping and reporting systems, QA systems, etc. Please provide some estimate of the impact on state resources, and request comment from the states on the accu racy of these estimates 39) Pg 253. indicates that the 4 visibility preference studies differ on “specific wording used to frame questions used in the group interview”. Please expand the discussion of these differences. Also, please explain how the wording used to frame the questions aligns with language that defines acceptability in the Clean Air Act. Did the researchers use the Clean Air Act as a starting point to define acceptability, and how was this translated to study subjects? 40) P g 256

- 257. Please no te that the DC and Denver studies have a roughly 2.5 fold difference (75 to 200 Mm

- 1) between the median visibility levels that were deemed

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review. acceptable. Please note that this high relative difference calls into question the reproducibility and reliability of the underlying studies. RIA Comments 1) Some commenters request clarification why GHG emissions rules for passenger vehicles and heavy

- duty vehicles were not included in the baseline, particularly given the inclusion of near

- road monitoring. 2) Some comment s would like to suggest an alternate baseline analysis be conducted that would include the Boiler MACT and CISWI rules in the baseline, particularly as they are expected to be final before this rule will be. Commenters would also suggest the Regional Haze policies (including any State

- specific regional haze controls or consent decrees that fall outside the CSAPR

- better

- then

- BART rulemaking) and the RICE rule be also included in this alternate baseline. 3) Some commenters note that characterization of the b aseline could have a major effect on the alternatives analysis, given the significantly lower costs and benefits of the 13/35 alternative. If inclusion of the GHG mobile source rules and the Boiler MACT rules has a signi ficant effect on the baseline, it could drastically change the benefit

- cost ratio of the preferred alternative. 4) Some commenters note that i t is not clear why EPA has not attempted to “estimate costs that government agencies may incu r for managing the requ irement,” and request clarification whether this will be done for the final RIA. These commenters note that i t would be helpful for EPA to provide a rough estimate of how much it would cost for state and local air authorities to implement a new secondary standard while seeking public comment on the issue. 5) The document states that “Costs of federal and state administration of SIP program” is an un

- quantified cost, but also says that it could bias the overall cost estimate high or low. If these costs are n ot estimated, it is not clear how they could necessarily lead to a high bias. Please clarify. 6) Some Commenters suggest that EPA itemize and take comment on the areas where the RIA has not provided a quantitative analysis of the potential impacts of the ru le. For example, EPA does not provide a quantitative estimate of the cost or benefits of additional permitting requirements in both attainment and non

- attainment areas. PSD permitting is one of the earliest and potentially most important impacts of a N AAQs. In addition, EPA does not provide an analysis of the costs and benefits of

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review.

non - attainment, over and above the controls that need be adopted in order to attain. For example, an area being found in non

- attainment certainly will be impacted, even if they were to be able to rely completely on “on the books” controls to attain. NSR permitting, and the requirement to find offsets for new construction, perhaps is the most prominent example, but other NAAQs obligations such as SIP development and approv al and other showings required by a non

- attainment decision could also be important and have impacts. 7) Some commenters suggest that EPA include a note of explanation as to why DSI is not included as a possible SO2 control strategy, along with flue gas de sulfurization. DOE suggests EPA may want to consider this control technology as a sensitivity case in future analysis for the final revision of the standard. 8) Some commenters note that EPA appears to have used dated reports (2009 and 2006 and many older) to calculate economic value of avoided PM2.5 morbidities and premature deaths. 9) On page 5

- 33, commenters suggest that EPA clarify how one report is selected over another when more than one report exists that detail pollutant results. 10) EPA assumes that all fine particles, regardless of their chemical composition, are equally potent in causing premature mortality. Commenters encourage EPA to review literature suggesting that there may be evidence to support a differentiation in the assoc iation of health endpoints with specific components of PM2.5. 11) Section 11.3.1, Page 11

- 4: “However, the environmental protection sector often sees immediate employment effects.” Please provide a definition and examples of the “environmental protection sect or.” 12) Chapter_4

-- Control_Strategies_5

- 22

- 12_revised_clean.docx Page 4

- 6: Under area sources: some commenters suggest changes that cite use of Basic Smoke Management Practices and Establishment of Smoke Management Programs rather than current controls suggested of “Episodic Bans on Open Burning, Substituting Chipping for Open Burning and Household Burning and Seasonal Ban on Agricultural Burning.” 13) Page 4

- 10: The following sentence was in the draft: “Controls for area sources were applied to: home heati ng, restaurant operations, as well as controls on burning.” Yet when one reviews the emission inventories used for modeling of the PM NAAQS,

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review. open burning was not cited and the 2005 NEI had very little prescribed fire and open burning included based on the summary of the 2005 NEI from the 2005 National Air Toxics Assessment. Please clarify what was done and what controls are implied. If reductions were applied to prescribed fire, we are likely perpetuating the potential for catastrophic wildfire and emissi ons. This also relevant with statement on pages 4

- 14 to 4

- 15 that says ”Area source controls assume a constant estimate of emission reductions, despite variability in extent and scale of application.” 14) Chapter_10

-- Secondary_Standard_0529 Page 2: Curren t proposal states: “Smoke from wildfires is an important contributor to visibility impairment in the western U.S., and particulate nitrate contributes to decreased visibility in California and the upper Midwest, particularly during the winter (U.S. EPA, 20 09).” Commenters point out that b y EPA Regional Haze Guidance the smoke from wildfires is considered natural background and makes this statement potentially very misleading as impairment is usually associa ted with anthropogenic sources. 15) Commenters reques t that EPA better explain why coarse PM does not have benefit cost analysis for alternative standards (e.g., this was already done last time around and there is no change) and provide ref erence for most recent analysis. 16) P. ES

- 3 “The baseline includes redu ctions already achieved as a result of national regulations, reductions expected prior to 2020 from recently promulgated national regulations (i.e., reductions that were not realized before 2005 but are expected prior to attainment of the current PM standa rd)...” Please explain why 2005 is the relevant year for baseline (versus, say 2012). 17) P.2

- 13 “ For example, Figure 2

- 8 shows that visual range increased nearly 50% in the eastern U.S. since 1992.” Please explain how the Figure shows this. Charts don’t seem to show distribution of days between three categories. Visibility on best days may be getting better, but might there be fewer best days, leading to an overall decrease in visual range? 18) P. 6

- 15 Commenters suggest Striking the following language from footn ote 14 “EPA believes the study has received adequate review and has been cited in numerous peer - reviewed publications (e.g., Chestnut and Dennis, 1997).” Commenters note that being cited doesn’t necessarily lend specific credibility to a study (somebody co uld be citing it as a bad example). 19) P. 10

- 5 Figure 10

- 2 should indicate the year in the title.

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review.

20) Ch. 10 In general there should be more detailed discussion regarding the uncertainty of modeling attainment with secondary NAAQS. In particular it should be emphasized that although EPA does not currently believe that any county that is in compliance with primary will violate secondary, different traje ctories may lead to cases in which the secondary standard is binding.

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review.
I. Communicati on of Public Health Information Sections 319(a)(1) and (3) of the CAA require the EPA to establish a uniform air quality index for reporting of air quality

. These sections specifically direct the Administrator to ‘‘promulgate regulations establishing an air quality monitoring system throughout the United States which utilizes uniform air quality monitoring criteria and methodology and measures such air quality according to a uniform air quality index’’ and ‘‘provides for daily analysis and reporting of air quality based upon such uniform air quality index...’’ In 1979, the EPA established requirements for index reporting (44 FR 27598, May 10, 1979)

. The requireme nt for State and local agencies to report the AQI appears in 40 CFR 58.50 and the specific requirements (e.g., what to report, how to report, reporting frequency, calculations) are in appendix G to 40 CFR part 58. Information on the public health implicati ons of ambient concentrations of criteria pollutants is currently made available primarily through EPA’s AQI program

. The current AQI has been in use since its inception in 1999. 1 It provides accurate, timely, and easily understandable information about da ily levels of pollution (40 CFR 58.50)

. The AQI establishes a nationally uniform system of indexing pollution levels for ozone, carbon monoxide, nitrogen dioxide, PM and sulfur dioxide

. The AQI is also recognized internationally as a proven tool to effecti vely communicate air quality information to the public

. In fact, many countries have created similar indices based on the AQI

. The AQI converts pollutant concentrations in a community’s air to a number on a scale

1 In 1976, the EPA established a nationally uniform air quality index, then called the Pollutant Standard Index (PSI), for use by State and local agencies on a voluntary basis (41 FR 37660, September 7, 1976)

. In August 1999, the EPA adopted revisions to this air quality index (64 FR 42530, August 4, 1999) and renamed the index the AQI

.

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review.
from 0 to 500

. Reported AQI values enable the public to know whether air pollution levels in a particular location are characterized as good (0

– 50), moderate (51

– 100), unhealthy for sensitive groups (101

– 150), unhealthy (151

– 200), very unhealthy (201

– 300), or hazardous (300

– 500). The AQI index va lue of 100 typically corresponds to the level of the short

- term (e.g., daily or hourly standard) NAAQS for each pollutant. Below an index value of 100, an intermediate value of 50 was defined either as the level of the annual standard if an annual standard has been established (e.g., PM 2.5 , nitrogen dioxide), or as a concentration equal to one

- half the value of the short

- term standard used to define an index value of 100 (e.g., carbon monoxide). An AQI value greater than 100 means that a pollutant is in one of the unhealthy categories (i.e., unhealthy for sensitive groups, unhealthy, very unhealthy, or hazardous) on a given day

. An AQI value at or below 100 means that a pollutant concentration is in one of the satisfactory categories (i.e., moderate or good)

. Decisions about the pollutant concentrations at which to set the various AQI breakpoints that delineate the various AQI categories draw directly from the underlying health information that supports the NAAQS review. Historically, s tate and local agencies have primarily used the AQI to provide general information to the public about air quality and its relationship to public health

. For more than a decade, many s tates and local agencies, as well as the EPA and other Federal agencies, have been developing n ew and innovative programs and initiatives to provide more information to the public, in a more timely way

. These initiatives, including air quality forecasting, real

- time data reporting through the AIRNow website 2 , and air quality action day programs, can serve to provide useful, up

- to

- date, and timely information to the public about air pollution and its effects

. Such information will help individuals take actions to avoid or to reduce exposures to

2 See http://w ww.airnow.gov/index.cfm?action=airnow.showlocal&cityid=204

.

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review. ambient pollution at levels of concern to them and can en courage the public to take actions that will reduce air pollution on days when levels are projected to be at levels of concern to local communities

. Thus, these programs have significantly broadened the ways in which s tate and local agencies can meet the n ationally uniform AQI reporting requirements, and are co ntributing
to s tate and local efforts to provide community health protection and to attain or maintain compliance with the NAAQS

. The EPA and s tate and local agencies recognize that these
programs are interrelated with AQI reporting and with the information on the effects of air pollution on public health that is generated through the periodic review, and revision when appropriate, of the NAAQS. In recognition of the proposed changes to the suite of pr imary PM 2.5 standards summarized in section I II.F above, the EPA proposes conforming changes to the AQI to be consistent with the proposed changes to the standards

. The health effects information that supports the proposed decisions on the PM 2.5 standards as discussed in section I II.B above is also the basis for the proposed changes in the AQI discussed below in this section

. The EPA intends to finalize conforming changes to the AQI in conjunction with the Agency’s final decisions on the primary annual and 24

- hour PM 2.5 standards, if revisions to such standards are promulgated

. Note that, currently, we are cautioning members of sensitive groups at the AQI value of 100 at 35 μg/m 3 , 24

- hour average, because this is the level that was provided in gui dance (Harnett, 2009, Attachment B) which, in essence, superseded the AQI value of 100 established in 1999 (64 FR 42530, August 4, 1999). 3 With respect to an AQI value of 50, as discussed above, the historical approach is to set it at the same level of the annual standard, if there is one

. This is consistent with the current AQI

3 In addition, this guidance document recommended an AQI value of 150 at 55 μg/m 3 , 24

- hour average, which is in use by many State and local agencies (Harnett, 2009, Attachment B). Comment [A1]: The last official FR notice which listed the AQI for PM2.5 is: Federal Register: June 26, 2009 (Volume 74, Number 122. I believe, like the NAAQS, EPA should post the current AQI that is being used. These references are vague and having looked at them I l anded on the last FR notice above. It appears the number at 100 Index level is not in alignment.

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review.
sub

- index for PM 2.5 and the EPA sees no basis for deviating from this approach

. Thus, the EPA
propos es to set an AQI value of 50 at 12 μg/m 3 , 24

- hour average, the same level as the proposed annual PM 2.5 standard

. If the annual standard is set at a different level, an AQI value of 50 will be set at the level of the annual PM 2.5 standard that is promulgated

. With respect to an AQI value of 100, there are two general approaches that could be used to select the associated PM 2.5 level

. By far the most common approach, which has been used with the other sub

- indices as discussed above, is to set an AQI value of 100 at the same level as the short

- term standard

. The EPA recognizes that som e s tate and local air quality agencies have expressed a strong preference that the Agency set an AQI value of 100 equal to any short

- term standard

. These agencies typically express the view that this linkage is useful for the purpose of communicating wi th the public about the standard, as well as the health impacts associated with daily air quality

. The second approach is to directly evaluate the health effects evidence to select the level for an AQI value of 100 which is the basis for advisories to individuals in sensitive groups. The EPA is considering this alternative approach in recognition that, as proposed, the 24

- hour PM 2.5 standard provides supplemental protection against effects associated with short

- term exposures of PM 2.5 by working in conj unction with the annual standard to reduce 24

- hour exposures to
PM 2.5 . The EPA recognizes that some state and local air quality agencies have expressed support for this alternative approach, when the annual standard provides some protection from effects

as sociated with short

- term exposures. This alternative approach of evaluating the health evidence directly results in the consideration of a range of 35 to 30 μg/m 3 , 24

- hour average, based on the discussion of the health information pertaining to the level o f the 24

- hour standard in section III.E.4 above. Setting an AQI value of 100 at the upper end of the range (35 μg/m 3 , 24

- hour Comment [A2]: The use of different state

- by

state AQI values is confusing to the public and leads to public inaction due to potentially different messaging about serious air quality conditions. Consider: Although state and local air agencies have used AQI values and indices that differ from EPA, in an emergency situation, communication to the public should be consistent to afford the best potential for public confidence a nd proactive response to the air quality conditions. Comment [A3]: This entire section reiterates Section III. B above and is not needed. This led me and others to think that EPA is proposing two options for the AQI. I suggest striking the whole highlighted section.

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review. average) would place more weight on the multi

- city, short

- term exposure studies that generally support retaining the current 24

- ho ur standard level at 35 μg/m 3 in conjunction with lowering the level of the annual standard to 12 μg/m 3 . Setting an AQI value of 100 at the lower end of the range (30 μg/m 3 , 24

- hour average) would place more weight on the limited evidence from one multi

- ci ty study (Bell et al., 2008) that reported positive and statistically significant effects with an overall 98 th percentile value below 35 μg/m 3 , 24

- hour average, in conjunction with an overall long

- term mean concentration slightly less than 13 μg/m 3 (US EPA , 2011a, p. 2

- 84). Both of these approaches result in the consideration of setting an AQI value of 100 for the PM 2.5 sub

- index within the range of 35 to 30 μg/m 3 , 24

- hour average. In making a final decision on the air quality level for an AQI value of 100 , the EPA will first decide on the approach that is appropriate, and then the level that is consistent with that approach. If the first approach is selected, the Agency will set the AQI value of 100 at the level of the 24

- hour PM 2.5 that is promulgated. If the second approach is selected, the Agency will base the decision to set the PM 2.5 level for an AQI value of 100 by evaluating the health effects evidence. The EPA strongly encourages state and local air quality agencies that use the AQI to comment on both the approach and the level at which to set an AQI value of 100. With respect to an AQI value of 150, this level is based upon the same health effects information that informs the selection of the level of the 24

- hour standard and the AQI value of
100

. As noted above, in guidance the EPA indicated that a 55 μg/m 3 , 24

- hour average, PM 2.5 level should be used for an AQI value of 150, in conjunction with an AQI value of 100 at 35 μg/m 3 , 24

- hour average (Harnett, 2009. Attachment B ). In considering wha t level to propose for an AQI value of 150, we still believe that the health effects evidence indicates that the level of 55 μg/m 3 , 24

- hour average, is appropriate to use in conjunction with an AQI value of 100 set at 35 Comment [A4]: Confusing, please strike.

Comment [A5]: This clearly says that EPA is open to two different approaches and that is for the AQI and NOT the NAAQS 24hr standard. Consider: changing section to read : T he EPA propos es to set an AQI value of 100 at either 35 or 30 μg/m3, 24

- hour average the same level s as the proposed short term PM 2.5 standard

. If the 24

- hour standard is set at a different level, an AQI value of 10 0 will be set at the level of the 24

- hour PM 2.5 standard that is promulgated

.

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review. μg/m 3 . If, however, the EPA decides to set an AQI value of 100 at 30 μg/m 3
, using one of the two approaches discussed above , then the EPA would adjust an AQI value of 150 proportionally to the PM 2.5 level of 50 μg/m 3 , 24

- hour average. The Agency’s approach to selecting the levels at whic h to set the AQI values of 100 and 150 inherently recognizes that the epidemiological evidence upon which these decisions are based provides no evidence of discernible thresholds, below which effects do not occur in either sensitive groups or in the genera l population, at which to set these two breakpoints. Therefore, EPA concludes the use of a proportional adjustment is appropriate

. Thus, if the EPA sets an AQI value of 100 at the PM 2.5 level of 35 μg/m 3 , 24

- hour average, the Agency proposes to set an AQI value of 150 at the PM 2.5 level of 55 μg/m 3 , 24

- hour
average . However, if the EPA sets an AQI value of 100 at the PM 2.5 level of 30 μg/m 3 , 24

- hour average, the Agency proposes to set an AQI value of 150 at the PM 2.5 level of 50 μg/m 3 , 24

- hour
average . The EPA also propos es to set an AQI value of 500 at 350 500 μg/m 3 , as discussed below, and propos es proportional revisions to the AQI breakpoints between the 150 and 500 levels

. The proposed breakpoints are shown in Table 2 below

. A review of the histor y of the AQI value of 500 for PM 10 and of the AQI value of 500 for PM 2.5 is useful background for explaining the basis for maintaining proposing to set an AQI value of 500 at 500 350 μg/m 3 , 24

- hour average, for
PM 2.5 . The current AQI value of 500 for PM 10 w as set in 1987 at the level of 600 μg/m 3 , 24

- hour average, on the basis of increased mortality associated with historical wintertime pollution episodes in London (52 FR 24687 to 24688, July 1, 1987)

. Particle concentrations , dominated with sulfate from coal burning for heating during these episodes, measured by the British Smoke method, were in the range of 500 to 1000 μg/m 3

. In the 1987 rulemaking that established the upper bound index value for PM 10 , the EPA cited a generally held opinion that the Brit ish Smoke Comment [A6]: Strike as this adds to the con fusion.

Comment [A7]: 500

Comment [A8]: Table 2 should reflect current AQI and propsed with proportional steps up to Index 500 and 500 μg/m 3

Comment [A9]: Note that previously EPA cites that there is indication that sulfate dominated particulate is a pollutant with specific negative affects (see page 104 and the linkage of mortality and secondary sulfate which was a significant portion of the pollution in th e London pollution). Note woodsmoke is very low in secondary sulfate constituency .

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review. method measures PM with a cutpoint of approximately 4.5 microns (52 FR 24688, July 1, 1987)

. In establishing this value for PM 10 , we assumed that concentrations of PM 10 , which includes both coarse and fine particles, during episodes of concern, w ould be about 100 μg/m 3 higher than the PM concentration measured in terms of British Smoke (52 FR 24688, July 1, 1987)

. The upper bound index value of 600 μg/m 3 was developed by selecting the lower end of the range of harmful concentrations during the his torical wintertime pollution episodes in London (500 μg/m 3 ) and adding a margin of 100 μg/m 3 to account for this measurement difference

. The
current PM 2.5 concentration corresponding to an AQI value of 500 is 500 μg/m 3 , 24

- hour
average . This was proposed i n 1998 and finalized in 1999 (63 FR 67829, December 9, 1998, and 64 FR 42530, August 4, 1999, respectively)

. Because there were few PM 2.5 monitoring data available at that time, the proposal was based on the stated assumption that PM concentrations

measure d by the British Smoke method are approximately equivalent to PM 2.5 concentrations

.

Table 2. Proposed Revisions to PM 2.5 Sub

- Index AQI Category Index Values Proposed Breakpoints (μg/m 3 , 24

- hour average) Good 0

- 50 0.0

– 12.4 Moderate 51

- 100 12.5

– (30.4

- 35.4) Unhealthy for Sensitive Groups 101

- 150 (30.5

- 35.5)

– (50.4

- 55.4) Unhealthy 151

- 200 (50.5

- 55.5)

- 140.4 150.4 Very Unhealthy 201

- 300 140.5

- 210. 4 150.5

- 250.4 Hazardous 301

- 400 210.5

- 280.4 250.4

- 350.4

401

- 500 280.5

- 350.4 350.5

- 500
In considering revisions to an AQI value of 500 for PM 2.5 , the EPA has taken note that the proposed and final actions in 1998 and 1999 were based on an assumption of approximate equivalence between the British Smoke method and the current PM 2.5 method

. This assumption is not entirely consistent with the view cited in 1987 that the British Smoke method has a cutoff Comment [A10]: Note, need the table to show current AQI for PM2.5 and the proposed changes as shown here.

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review. of 4.5 microns (52 FR 24688, July 1, 1987)

. Because of the dramatic increase in PM 2.5 monitoring data since that rulemaking, th e EPA considers it appropriate to set the AQI value of 500 for PM 2.5 at a level below 500 μg/m 3 so that it retains is current is more consisten cy t with the findings from the London episodes and with the AQI value of 500 for PM 10 . On average , about 60 percent of ambient PM 10 measured in the northeastern, southeastern, and industrial midwest portions of the U.S. consists of PM 2.5 . 4 Using the 60 percent factor to scale the AQI value of 500 for PM 10 (600 μg/m 3 ) results in an AQI value of 500 for
PM 2.5 of a bout 350 μg/m 3 . The Agency believes it is appropriate that this scaling approach results in a PM 2.5 value for the upper bound index value that is below the 500 μg/m 3
concentration of PM 4.5 by the British Smoke method. The EPA therefore proposes this level for the upper bound level of the PM 2.5 sub

- index of the AQI. The EPA has used the historical wintertime pollution episodes in London to propose setting an AQI value of 500 for PM 2.5 as described above because it is still the best available information

- t here is little information about similar, more recent, air pollution episodes and associated impacts on community health upon which to base a decision

. However, the limited number of studies cited in the Integrated Science Assessment that evaluated wood smoke health impacts found effects such as cardiovascular morbidity and mortality (e.g., Delfino et al., 2009; Mar et al., 2000; Sarnat et al., 2008) as well as respiratory effects (e.g., Barregard et al., 2008 ; Delfino et al., 2009; Schreuder et al., 2006) at much lower levels (US EPA, 2009a, sections 6.2 and 6.6)

. These recent health studies provide additional qualitative support for lowering the air quality level associated with an AQI value of 500 to 350 μg/m 3 and, therefore, also lowering the

4 More specifically, in 2001 to 2003, the median of the ratio of 24

- hour PM 2.5 and PM 10 among monitoring sites in the northeastern, southeastern, and industrial midwest portions of the U.S to the annual average was between 0.60 and 0.65 (US EPA, 2005, Figure 2

- 19 ). Comment [A11]: This is not geographically representative of the US and yet the AQI is a na tional metric. A query of the EPA’s AQS shows high values of PM2.5 are most frequently associated with wildfires and are not found in some the regions used by EPA.

Comment [A12]: Srike this section.

Comment [A13]: Note: This work is based on indoor smoke exposure, based on 13 subj ects, and two 4 hr sessions. No follow up on long term health effects.

### Summary of Interagency Working Comments on Draft Language under

EO12866/13563 Interagency Review. Subject to Further Policy Review.
other levels in the range of AQI values between 150 and 500

. For the intermediate breakpoints in the AQI between the values of 150 and 500, the EPA
propos es PM 2.5 concentrations that generally reflect a linear relationship between increasing index values and i ncreasing PM 2.5 values (Table 2 above)

. The available scientific evidence of health effects related to population exposures to PM 2.5 concentrations between the level of the
24

- hour standard and an AQI value of 500 suggest a continuum of effects in this ran ge, with increasing PM 2.5 concentrations being associated with increasingly larger numbers of people likely to experience such effects

. The generally linear relationship between AQI values and
PM 2.5 concentrations in this range is consistent with the healt h evidence

. This also is consistent with the Agency’s practice of setting breakpoints in symmetrical fashion where health effects information does not suggest particular levels. EPA is interested in alternative approaches to the setting of the upper level s of the AQI and if further research is available to base changes to the proposed values here, welcome such information.