National Ambient Air Quality Standards for Ozone:Summary of Final RuleBriefing for OMBU.S. Environmental Protection AgencySeptember 3, 2015Key Messages•Court-ordered deadline for final rule signature is October 1, 2015.•Strong body of scientific evidence supports revising the current 75 ppb primary standardlevel, especially to protect at-risk groups, including children and asthmatics.•Strong body of scientific evidence supports strengthening thecurrent secondarystandard•Additionally, the U.S. Court of Appeals (D.C. Circuit) remanded the secondary standard back to EPA in2013•On November 25, 2014, we proposed to revise both the primary (health) and secondary(welfare) ozone standards:•Proposed to strengthenthe primary standard to a levelbetween 65 – 70ppb; solicitedcomment on lower levels, down to 60 ppb,and on retaining current standard.•Proposed to revise the secondary standard towithin the range of the primary standard (65 –70 ppb); solicited comment on separate secondary standard at alternative levels andalternative form (W126).•Received > 430,000 publiccomments on the proposal;held 3 public hearings•The Administrator has concluded that a primary standard of 70 ppb provides requisiteprotection with an adequate margin of safety and a secondary standard of 70 ppb wouldprotect the public welfare from any known or anticipated adverse effects.EO12866_Ozone_NAAQS_NFR_RIN2060-AP38_9/3/15FOR INTERAGENCY REVIEW ONLY-- DO NOT DISTRIBUTE2NAAQS Statutory Requirements (CAA§109)•Primary (health-based) standards“shall be ambient air quality standards . . .whichin the judgment of the Administrator “ are“requisite” to protectpublic health, includingat-risk groups, with an “adequate margin of safety.”•Secondary (welfare-based) standards:“...specify a level of air quality theattainment and maintenance of which” inthe “judgment of the Administrator” is“requisite to protect the public welfarefrom any known or anticipated adverseeffects.”•An independent scientific review committee (currently the Clean Air ScientificAdvisory Committee [CASAC]), shall review the science and standards and “shallrecommend to the Administrator any new . . .standards and revisionsof existing . . .standards as may be appropriate.”•In setting standards:•EPA is required to engagein “reasoned decision making”.•EPA may not consider cost in setting the level of the standard.Rather, cost is considered indeveloping control strategies to meet the standards.EO12866_Ozone_NAAQS_NFR_RIN2060-AP38_9/3/15FOR INTERAGENCY REVIEW ONLY-- DO NOT DISTRIBUTE3Science-Based Conclusions on Primary Standard•Over 1,000 new studies since last review; strongest evidence for respiratory effects (includingrespiratory mortality) from short-term ozone exposures.•Controlled human exposure studies show wide range of respiratory effects following exposuresfrom 60 to 80 ppb.New controlled human exposure studies in this review:– At 72 ppb: “Adverse” combinationof lung function decrements and respiratory symptoms observed(Schelegle et al., 2009)– At 60 ppb: Lung function decrements and airway inflammation observed(Kim et al., 2011); adversity ofeffects is less clear•At-risk groups include: People with asthma (especially children withasthma) and other lungdiseases; children and older adults; all people who are activeoutdoors (especially outdoorworkers).•Epidemiological studies show evidence for associations with mortality/morbidity; some studiesreport associations with air quality likelyto have been allowed by the current standard.•EPA conducted a Risk & Exposure Assessment (REA) to estimate ozone exposures of concern≥60, 70, 80 ppb; the risk of ozone-induced lung function decrements; and the risk of ozoneassociated mortality/morbidity for air quality meeting the current and potential alternativestandards.•CASAC: Science supports revising the level towithin the range of 60 – 70 ppb; policy advicewas to set level below 70 ppb to provide greater margin of safety.EO12866_Ozone_NAAQS_NFR_RIN2060-AP38_9/3/15FOR INTERAGENCY REVIEW ONLY-- DO NOT DISTRIBUTE4Overview of Primary Standard Comments•Most commenters supported either retaining the current standard of 75 ppb or revisingto 60 ppb; some state agencies supported the proposed range of 65 - 70 ppb.•Retain current standard level (industry and some states)•Lack of support in evidence,exposure/risk assessments;uncertainties too great•Background ozone concentrations near/at/above proposedstandard range•Negative economic impactsof lower level will create health risksand more nonattainment areas willresult in job losses•Set standard level at 60 ppb (environmental and public health advocates)•Stronger controlled human exposure evidence in this reviewsupports a level of 60 ppb•Adverse health effects at 60 ppb in6.6-hour exposure studies of healthy, young adults; effects likelygreater in at-risk populations, including asthmatic children,and with 8-hour exposures•Point to CASAC advice that: a level of 70 ppb provides “little margin of safety for the protection ofpublic health, particularly for sensitive subpopulations”EO12866_Ozone_NAAQS_NFR_RIN2060-AP38_9/3/15FOR INTERAGENCY REVIEW ONLY-- DO NOT DISTRIBUTE5Administrator’s Final Decision on Level of Primary Standard•A standard with a level of 70 ppb isrequisite to protect public health with an adequate margin of safety.•70 ppb is below the level at which “adverse” combination of lung function decrements and respiratorysymptoms observed in clinical studies (e.g., 72 ppb).•Further considered the protection 70 ppb offers against exposures to ozone concentrations shown incontrolled human exposure studiesto cause respiratory effects.•Protection depends on variations in ozone concentrations across an area, as well as activity patterns and ventilationrates.•A standard level of 70 ppb eliminates almost all exposures to ozone concentrations of 80 and70 ppb, for which thereis strongest evidence of adverse effects.•A standard of 70 ppb also substantially limitsexposures to levelsas low as 60 ppb.•While effects have been shown to occur following exposureto 60 ppb, adversity ofthese effects is less clear.However, CASAC did advise limiting exposures to 60 ppb.•Repeated exposure increaseslikelihood of more serious effects, leading Administrator to focus on limitingmultiple (2 or more) exposures.•A level of 70 ppb protects >98% ofchildren from experiencing repeatedexposures to 60 ppb, providing anadequate margin of safety.•A standard of 70 ppb is also estimated to reduceoccurrences of ozone-inducedlung-function decrements≥10% and 15% and to reduce ambientozone concentrations associatedwith mortality and morbidity inepidemiologic studies.•A level below 70 ppb would be more than “requisite”to protect public health; wouldplace significant emphasison reducing even lower ozone concentrations, despite considerable uncertainty in the occurrence of adverseeffects at those levels.EO12866_Ozone_NAAQS_NFR_RIN2060-AP38_9/3/15FOR INTERAGENCY REVIEW ONLY-- DO NOT DISTRIBUTE6Air Quality Index•Proposed new breakpoints based on the proposed primary standard and information from thehealth studies examined inthe review; EPA proposed:•Setting the 100 level of the AQI at the same level as the revised primary ozone NAAQS•Adjusting AQI breakpoints at the lower end of each range (i.e., AQIvalues of 50, 150, 200 and 300)•For the AQI breakpoint between Good and Moderate,we took comment on a range (49-50 or 54-55)•Almost all commenters supported proposed changes•Final Decision:•Revising the 100-level AQI value tothe level of the standard (70 ppb)•Revising the “Good/Moderate” breakpoint to be15 ppb under the standard level (54/55 ppb); thisproportional adjustment is consistent with past reviews•Other category breakpoints (Unhealthy and Very Unhealthy) are revised as proposedEO12866_Ozone_NAAQS_NFR_RIN2060-AP38_9/3/15FOR INTERAGENCY REVIEW ONLY-- DO NOT DISTRIBUTE7AQI Category AQI Values Current Breakpointsppb, 8-hour averageFinal Breakpointsppb, 8-hour averageGood 0 - 50 0-59 0-54Moderate 51 – 100 60-75 55-70Unhealthy forSensitive Groups101 - 150 76-95 71-85Unhealthy 151 – 200 96-115 86-105Very Unhealthy 201 – 300 116-374 106-200Hazardous 301 - 500 375 toSignificant Harm Level201 toSignificant Harm LevelScience-Based Conclusions on Secondary Standard•Ozone has detrimental effects on vegetation, including both crops and trees.•Plant response to ozonedepends on both the leveland cumulativenature of exposures over the growingseason. Specialized exposuremetrics (such as W126 cumulativeweighted index) are used to assesspotential impacts on vegetation.•Studies show that effects on sensitive tree species (e.g., reduced growth and productivity) could haveadverse implications for ecosystems (e.g., reduced ecosystem productivity, alteration of water availability inwatersheds, reduced carbon sequestration, changes in community composition).•There is little established quantitative information for informing judgments on adversity of these effects tothe public welfare.•CASAC advised that the secondary standard should be in terms of acumulative, seasonalform (i.e., W126) set at a level within the range of an annual index of 7 to 15 ppm-hrs.•EPA proposed to retain the current form andrevise the secondary standard level to withinthe range of the primary standard (65 – 70 ppb); solicited commenton separate secondarystandard with an alternative form (W126).•Public comments mixed; somesupported using same formas primary, some supportedW126-based form; some supportedretention of current standard.EO12866_Ozone_NAAQS_NFR_RIN2060-AP38_9/3/15FOR INTERAGENCY REVIEW ONLY-- DO NOT DISTRIBUTE8Administrator’s Final Decision on Secondary Welfare-Based Standard•Retain current form of secondary standardand revise level to 70 ppb (same asprimary standard).•Such a standard will provide the requisiteprotection of the public welfare from anyknown or anticipated adverse effects.•Focus is on ozone effects on treeseedling growth as a proxy (orsurrogate) for the full array ofvegetation-related effects of ozone.•A cumulative, seasonal exposure metric (the W126 index) is used for assessing growth-related effectsof ozone and for associatedjudgments about the desiredpublic welfare protection.•Consideration is given to CASAC advice on using estimates ofrelative biomass loss (RBL) for treeseedlings and their view that 6% RBL inthe median studied speciesis unacceptably high.•The Administrator judges it appropriate for the revised standard to generally limit cumulative seasonalexposures to 17 ppm-hrs or lower, in terms of theW126 index, which air quality analyses indicate canbe achieved by revising the level ofthe current standard to 70 ppb.•In accordance with the 2013judicial remand of the 2008secondary standard, thisrulemaking fully explains theAdministrator’s conclusions andjudgments in support ofthis decision.EO12866_Ozone_NAAQS_NFR_RIN2060-AP38_9/3/15FOR INTERAGENCY REVIEW ONLY-- DO NOT DISTRIBUTE9Monitoring Aspects of the Rule –Finalized as Proposed with Minor Updates•Updates to the Photochemical Assessment Monitoring Stations (PAMS)Network (reduce redundancy, improve geographic distribution, addflexible component)•Extension of the ozone monitoring seasonin 32 states and D.C. (majorityof changes were by 1 month)•Approved Federal Reference Method (FRM) for ambient measurementsof ozone while retaining existingFRM and Federal Equivalent Methods(FEMS)•New Appendix U to Part 50 (datahandling provisions for determiningcompliance with the revised NAAQS)EO12866_Ozone_NAAQS_NFR_RIN2060-AP38_9/3/15FOR INTERAGENCY REVIEW ONLY-- DO NOT DISTRIBUTE10PAMS Network Design•We are replacing the existing 20 year-oldmulti-site, enhancedozone network designwith an updated 2-part network design•Simplify existing network design by requiring PAMS measurements tobe collocated withexisting NCore sites in areas withpopulation of 1million or moreirrespective of O3NAAQS attainment status•Require states with moderate or above ozone non-attainment areasand states in theOzone Transport Region to develop and implement an EnhancedMonitoring Plan(EMP) to support flexibleapproaches for collecting data to understand ozone issues innew and existing high ozone areas•PAMS monitoring at NCore sites will become effective by June 1, 2019•EMPs submitted within two years of designationsor by July 1, 2020, whichever is later11EO12866_Ozone_NAAQS_NFR_RIN2060-AP38_9/3/15FOR INTERAGENCY REVIEW ONLY-- DO NOT DISTRIBUTEOzone Monitoring Seasons•EPA requires ozone monitoring only during the“ozone season” – the time of yearwhen weather conditions are most favorable for ozone formation. This seasonvaries by state: in some states with warmer climates, monitoring is required yearround; however, in states where the climate is colder, ozone monitoring is requiredfor as little as four months during the summertime.•Final rule extends the ozone monitoring season for 32 states and D.C.•One month for 23 of the 32 states and the District of Columbia•Additional extensions of two months to seven months including states where ozone can beelevated during the winter•Year-round seasons for all NCore multi-pollutant sites•Regional Administrators will still be allowed to approve changes to states’ ozonemonitoring seasons without rulemaking•Expanded monitoring season requirements will become effective January 1, 2017•Impact mitigated by the high proportion of monitors already being voluntarilyoperated on year-round basis12EO12866_Ozone_NAAQS_NFR_RIN2060-AP38_9/3/15FOR INTERAGENCY REVIEW ONLY-- DO NOT DISTRIBUTEPSD Permit Grandfathering Provision•Finalizing, as proposed, a grandfathering provision that will allow certain permits to beissued based on applicant’s demonstrated compliance with 2008NAAQS rather than2015 NAAQS. A permit application willqualify for grandfathering if either:•The application is determined tobe complete prior to the signature date of final NAAQS rule, or•The draft permit has been proposed for public comment prior to the effective date of NAAQS.•Note: This is the same set of criteria finalized for the 2012 PM2.5 NAAQS. Not all reviewingauthorities make formal completeness determinations, but for those that do path #1 generallyprovides a larger window for grandfathering than path #2.•Comments and Considerations:•Industry groups and some states support some type of grandfathering.•Opposing comments by coalitionof 8 environmental groupsinclude several legal argumentsconcluding the Act does not allowgrandfathering and EPA’s interpretation of authority is flawed.13EO12866_Ozone_NAAQS_NFR_RIN2060-AP38_9/3/15FOR INTERAGENCY REVIEW ONLY-- DO NOT DISTRIBUTESchedule for Submitting Demonstrations ofExceptional Events•To ensure EPA has adequate time to assessany state-submittedexceptional events(EE) demonstrations for 2014 – 2016 that wouldsubstantively affect designations (e.g.,nonattainment vs. attainment), we are establishing EE demonstration submissiondeadlines that split the available submission and review time between EPA and statesas follows:•October 1, 2016 ... for events affecting 2014 and 2015 ozone data•May 31, 2017 ... for events affecting 2016 ozone data (1 month prior to 120-day letters)•May 31, 2018 ... for 2017ozone data (would apply only under the optional3-yr designations schedule)•[Note: The schedule is actually a ‘delta schedule’that calculates submissiondeadlines based on thepromulgation date of the NAAQS. Applying thisdelta schedule to an October 1, 2015 NAAQSpromulgation results in the identified dates.]•Comments and Considerations:•Schedule is consistent with previous designations efforts andsupported by many commenters.•Several states requested more time to develop and submit demos for 2016 events.EO12866_Ozone_NAAQS_NFR_RIN2060-AP38_9/3/15FOR INTERAGENCY REVIEW ONLY-- DO NOT DISTRIBUTE14Ozone Designation and Implementation Schedules15Designation ScheduleScheduleTentative DateStateand TribeRecommendationsWithin 1 year afterNAAQSpromulgationOctober2016(Air quality data years:2013– 2015)Final DesignationWith 2 years afterNAAQS promulgation(Administrator hasdiscretion to useadditional year to collectmore information.)October 2017Effective date may vary(Air quality data years:2014–2016)Implementation ScheduleInfrastructure SIPWithin 3 years afterNAAQS promulgationOctober 2018NonattainmentSIPWithin 36- 48 monthsafterdesignationsdepending onclassificationOctober 2020Attainment Schedule by ClassificationScheduleMarginal3 years to attainModerate6 years to attainSerious9 years to attainSevere15 to 17 years to attainExtreme20 years to attainEO12866_Ozone_NAAQS_NFR_RIN2060-AP38_9/3/15FOR INTERAGENCY REVIEW ONLY-- DO NOT DISTRIBUTE