## Summary of Interage ncy Working Comments on Draft Language under

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

1 

###  For insertion on pg 33 of the preamble:

Wildfires pose a direct threat to public safety

– a threat that can be mitigated through management of wildland vegetation. Besides the physical threat to life and property posed by wildfires, they also affect air quality. Wildfire emissions do significantly contribute to periodic high levels and affects background levels of ozone (Jaffe, D.A. and N.L. Wagner, 2012), especiall y as standards approach background levels (Emery, C. et al., 2012). As has been acknowledged by EPA previously, fires play an important ecological role across the globe . Wildfire benefit s those plant and animal species that depend upon natural fires for pr opagation, habitat restoration, and reproduction , as well as myriad ecosystem functions (e.g., carbon sequestration)

. Attempts to exclude wildland fire have resulted in unintended consequences, including increased risks to both humans and ecosystems. Indee d, “Fire policy that focuses on [wildfire] suppression only, delays inevitable, promising more dangerous and destructive future...fires” (Stephens, S. et al., 2013). Most North American plant communities evolved with recurring fire and are dependent on recu rring fire for maintenance. Fires also reduce fuel load, unnatural understory, and tree density, helping to reduce the risk of catastrophic wildfires. The use of prescribed fire can influence the occurrence of catastrophic wildfires which will have direct impacts on high level impacts to ozone , background levels and subsequent public health effects. Wildfire and prescribed fire are both part of the natural background that will need further consideration during development of implementation rules for this
st andard. EPA has policies that allow for the exclusion of air quality monitoring data from design value calculations when they are substantially affected by certain background influences. However, the CAA requires the EPA to set the NAAQS at levels requisit e to protect public health and welfare without regard to the source of the pollutant

. The EPA is committed to working with Federal land managers, Tribes and the States, between this draft proposal and the final rule, to refine actions that address ozone im pacts while protecting and improving vegetation health and resilience to wildfire and climate risks.

Table 3, Page 162:

There is a lot of good information here, but there is not enough explanation to help the reader understand it. The title needs some work for clarity. Maybe some of the information goes in footnotes. We recommend stating in the title whether this table r efers to long term or short term exposure. Can footnotes to be used to provide the source of the concentration response function

– we assume this is
Jerrett et al?

Page 163:

## Summary of Interage ncy Working Comments on Draft Language under

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

2 The HREA also concludes that lower confidence should be placed in the results of the assessment of respiratory mortality risks associated with long

- term O 3 , primarily because that analysis is based on only one study, though that study is well

- designed, and because of the uncertainty in that study about the
existence and identifi cation of a potential threshold in the concentration

- response function (U.S. EPA, 2014a, section 9.6).

Page 164:

To evaluate the second issue, the HREA conducted national air quality modeling analyses. These analyses estimated the proportion of the U.S. population living in locations where seasonal averages of daily O 3 concentrations are estimated to decrease in response to reductions in NO X emissions, and the proportion living in locations where such seasonal averages are estimated to increase. Given the close relationship between changes in seasonal averages of daily O 3 concentrations and changes in seasonal mortality and morbidity risk estimates, this analysis informs consideration of the extent to which the risk results in urban study areas represent t he U.S. population as a whole. This representativeness analysis
indicates that the majority of the U.S. population lives in locations where reducing NO X emissions would be expected to result in decreases in warm season averages of daily maximum 8

- hour a mbient O 3 concentrations.

Page 167

To the extent adverse O 3 - attributable effects are more strongly supported for higher ambient concentrations (which are consistently reduced upon air quality adjustment), the impacts on risk estimates of increasing low O 3 concentrations reflect an important source of uncertainty.

Page 172:

In addition to lung function decrements, a A vailable studies have also evaluated either most of these effects (i.e., lung function decrements, respiratory symptoms or , airway inflammation) following exposures to O 3 concentrations below 75 ppb. Table 3

- 1 in the PA highlights the group mean results of individual controlled human exposure studies that have evaluated exposures of healthy adults to O 3 concentrations below 75 ppb (U.S. EPA, 2014c). The studies included in Table 3

- 1 of the PA indicate that some subjects experience a combination of lung function decrements and respiratory symptoms (after the fifth and sixth exercise period) following exposures to O 3 concentra tions as low as 72 ppb, 1 and lung

1 

### As noted above, for the 70 ppb exposure concentration Schele gle et al. (2009) reported that the actual 6.6

- hour mean exposure concentration was 72 ppb. Commented [A1]: Isn’t another key with the long term studies the potential for double counting?

Commented [A2]: Are there any environmental justice implications associated with the areas where there are NOx sources, and thus ozone levels expected to get higher?

Commented [A3]: Again, did EPA look at any EJ implications

– this is a risk

- risk trade off.

Commented [A4]: Consider edits to this para graph for transparency and clarity.

Commented [A5]: Per prior question about if these are the same people showing both stat sign diff in FEV1 and symptoms.

## Summary of Interage ncy Working Comments on Draft Language under

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

3 function decrements and airway inflammation following exposures to O 3 concentrations as low as 60 ppb.

The PA also notes consistent results in some panel studies of O 3 - associated lung function decrements. In particular, T t he PA notes that epidemiologic panel studies in children and adults consistently indicate
O 3 - associated lung function decrements when on

- site monitored concentrations were below 75 ppb, although with the evidence becom es ing less consistent at lower O 3 conc entrations (U.S. EPA, 2014c, section 3.1.4.1).

Page 180

iii. Important Uncertainties

The PA also notes that there are important uncertainties associated with analyses of air quality in locations of epidemiologic studies. For example, the PA notes that while multicity studies generally have greater statistical power and geographic coverage than single

- city studies, th ere is often greater uncertainty in conclusions about the extent to which multicity effect estimates reflect associations with air quality meeting the current standard (U.S. EPA, 2014c, section 1.3.1.2.1). This is particularly the case for the multicity st udies evaluated in this review with some study locations meeting the current standard and others violating that standard. Specifically for the four Canadian multicity studies discussed above, the PA notes that interpretation of air quality information is c omplicated by uncertainties in the extent to which multicity effect estimates can be attributed to ambient O 3 in the majority of locations, which would have met the current standard, versus O 3 in the smaller number of
locations that would have violated the standard.

Beginning on page 185:

For exposures of concern at or above 60 ppb, the PA highlights the following key observations at

a standard of 75 ppb:

(1) On average over the years 2006 to 2010, the current standard is estimated to allow approximatel y 10 to 18% of children in urban study areas to experience one or more exposures of concern at or above 60 ppb. Summing across urban study areas, these percentages correspond to almost 2.5 million children experiencing approximately 4 million exposures of concern at or above 60 ppb during a single O 3 season. Of these children, almost 250,000 are
asthmatics. (2) On average over the years 2006 to 2010, the current standard is estimated to allow approximately 3 to 8% of children in urban study areas to experie nce two or more exposures of
concern to O 3 concentrations at or above 60 ppb. Summing across the urban study areas, these percentages correspond to almost 900,000 children (including almost 90,000 asthmatic children) Commented [A6]: Some commenters are confused by the placement of this section (after the discussion of the “conclusions” of the PA . Is this section outlining the uncertainties in the conclusions or were these uncertainties taken into account when the conclusions we developed?

Commented [A7]: See parallel requests for adding “at a standard of 75 ppb” throughout pages 195

- 192 (for brevity, not all instances copied here)

Commented [A8]: Please develop a standard footnote that is used whenever EPA refers to the number of children. T hese numbers assume all child ren respond, extrapolated from the fact that only 10% of the healthy adults in the clinical studies respond ed gt 10% change in FEV. Given the assumption is that for children that would be adverse, there is margin of safety built in on a variety of levels, from a) the % responding; b) the severity of the re response. These are influenced by how severe the chil d’s asthma is and the extent of proper medical management of the child’s asthma. Thus, with increasing health care coverage, these numbers might be substantial over estimates.

## Summary of Interage ncy Working Comments on Draft Language under

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

4 estimated to experience at least two O 3 exposure concentrations at or above 60 ppb during a single O 3 season. (3) In the worst

- case years (i.e., those with the largest exposure estimates), the current standard is estimated to allow approximately 10 to 25% of children to experience one or more expo sures of concern at or above 60 ppb, and approximately 4 to 14% to experience two or more exposures of concern at or above 60 ppb. For exposures of concern at or above 70 ppb, the PA highlights the following key observations at a standard of 75 ppb :

(1) On a verage over the years 2006 to 2010, the current standard is estimated to allow up to approximately 3% of children in urban study areas to experience one or more exposures of concern at or above 70 ppb. Summing across urban study areas, almost 400,000 child ren (including almost 40,000 asthmatic children) are estimated to experience O 3 exposure concentrations at or above 70 ppb during a single O 3 season. (2) On average over the years 2006 to 2010, the current standard is estimated to allow less than 1%
of childr en in urban study areas to experience two or more exposures of concern to O 3 concentrations at or above 70 ppb. (3) In the worst

- case years, the current standard is estimated to allow approximately 1 to 8% of children to experience one or more exposures of co ncern at or above 70 ppb, and up to approximately 2% to experience two or more exposures of concern, at or above 70 ppb. For exposures of concern at or above 80 ppb, the PA highlights the observation that the current
standard is estimated to allow about 1 % or fewer children in urban study areas to experience exposures of concern at or above 80 ppb, even in years with the highest exposure estimates.

b. Lung function risk assessment

– key observations

As discussed above (II.C.3.a), the HREA estimates risks of moderate to large lung function decrements (i.e., FEV 1 decrements > 10%, 15%, or 20%) in school

- aged children (ages 5 to 18), asthmatic
school

- aged children, and the general adult population for 15 urban study areas. As for exposures of concern, the PA focuses on lung function risk estimates in children (including children with asthma).

Co mpared to risks associated with recent air quality, risk estimates for air quality just meeting the current standard are consistently smaller across urban study areas (U.S. EPA, 2014a, Appendix 6B). When averaged over the years evaluated in the HREA, risk reductions of up to about 40% were estimated compared to recent air quality. These reductions reflect the consistent decreases in relatively high ambient O 3 concentrations upon adjustment to just meet the current standard (U.S. EPA, 2014a, Chapter 4). Such reductions in estimated lung function risks are evident throughout urban study areas, including in urban cores and in surrounding areas (U.S. EPA, 2014, Appendix 9A).

Based on Figures 3

- 11 to 3

- 14 in the PA (U.S. EPA, 2014c), and the associated details de scribed in the HREA (U.S. EPA 2014a, chapter 6), the PA highlights key observations with regard to lung function

## Summary of Interage ncy Working Comments on Draft Language under

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

5 risks estimated in children for air quality adjusted to just meet the current standard. These key observations are presented below for FEV 1 dec rements > 10, 15, and 20%.

With regard to decrements > 10%, the PA highlights the following key observations at a standard of 75 ppb:

With regard to decrements > 15%, the PA highlights the following key observations at a standard of 75 ppb :

With regard to decrements > 20%, the PA highlights the following key observations at a standard of 75 ppb :

With regard to total mortality or morbidity associated with short

- term O 3 , the PA notes the

following at a standard of 75 ppb :

With regard to respir atory mortality associated with long

- term O 3 , the PA notes the following at a standard of 75 ppb :

Page 201 (same with footnote 89 on page 203)

Reductions in O 3 precursor emissions (i.e., NO X ) could also increase public health protection by reducing the ambient concentrations of pollutants other than O 3 . For example, in their advice on the second draft HREA CASAC acknowledged the potential for ambient NO 2 concentrations to be affected by changes in NO X emissions (Frey, 2014a, p. 10). Consistent with this , the PA notes that NO X emissions
contribute to ambient NO 2 , and NO X and VOCs can contribute to secondary formation of PM 2.5 constituents, including ammonium sulfate (NH 4 SO 4 ), ammonium nitrate (NH 4 NO 3 ), and organic carbon (OC). Therefore, at some times and in some locations, control strategies that would reduce NO X emissions (i.e., to meet an O 3 standard) could reduce ambient concentrations of NO 2 and PM 2.5 , resulting in health benefits beyond those directly associated with reducing ambient O 3 concentration s

.
Page 204:

In addition, based on the consistency of findings across studies and evidence for the coherence of results from different scientific disciplines, strong evidence indicates that certain populations are at increased risk of experiencing O 3 - r elated effects, including the most severe effects. These include populations and lifestages identified in previous reviews (i.e., people with asthma, children, older adults, outdoor workers) and populations identified since the last review (i.e., people wi th certain genotypes related to antioxidant and/or anti

- inflammatory status; people with reduced intake of certain antioxidant nutrients, such as Vitamins C and E). Commented [A9]: It is not clear why this paragraph is here

– why it is part of the argument a bout the choice of a standard for ozone vs. in the benefits analysis.

Commented [A10]: Please clarify the difference between “adequate evidence” as stated earlier in the document (e.g., page 134 states:

Overall, the factors for which the ISA concludes there is adequate evidence of increased risk for experiencing O 3 - related effects were related to asthma, lifestage (children and older adults), genetic variability, dietary factors, and working outdoors.

## Summary of Interage ncy Working Comments on Draft Language under

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

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