A STRUST & HOLDINGS INC. 44-129 MIKIOLA DRIVE, KANEOHE, HI 96744 PHONE: 808 2351890 FAX: 808 2350116 CELL: 808 5614688 EMAIL Richard@astrust.com WEB SITE www.hcr188c.com Richard H. Maruya

Rebecca Von Dem Hagen Alternatives and Emissions Reduction Branch Stratospheric Protection Division U.S. Environmental Protection Agency 1310 LStreet, NW, 10th Floor Washington, DC 20005

Comment by GaryWhitmyer onthe CMAQ Modeling September4, 2014

As perour conference call with EPAon August 21, 2014 during which Margaret informed all ofus on the CMAQ modeling:
We are herein also submitting comments on the CMAQ modeling that was conducted by ICF. This was cited in the proposed rule as ICF (2014a), entitled "Assessmentofthe PotentialImpacts ofHydrocarbon Refrigerants on Ground-Level Ozone Concentrations, February 24, 2014".
In this analysis, ICF modeled 4 scenarios:

- Scenario 1: rapid replacement ofall refrigerant uses with various hydrocarbon refrigerants;

- Scenario 2: rapid replacement ofall refrigerant uses except motorvehicle AC (MVAC) with hydrocarbon refrigerants;

- Scenario 3: rapid replacement ofall refrigerant uses except MVAC and chillers with hydrocarbon refrigerants; and

- Scenario 4: more gradual replacement of refrigerants with hydrocarbons ofvarious kinds.
The incremental ground-level ozone concentrations attributable to all hydrocarbon refrigerants and to specific hydrocarbons, such as propylene, for Scenarios 1, 2, and 3 were modeled using CMAQ and conservative assumptions for Houston, Atlanta, and Los Angeles. Upon review ofthe ICF (2014) study, a numberoflimitations with the CMAQ modeling conducted by ICF became apparent, as follows:(1) The assumption of rapid transition to all hydrocarbon refrigerants (in Scenarios 1, 2, and 3) is not a viable assumption, and disregards simple market realities; (2) The modeling focuses on only 1year (2005) ofmeteorological data. It is standard practice in ambient air modeling studiesto focus on several years (typically 5 years) ofmeteorological data in orderto capture a broaderdata setto reduce the uncertainties in the analysis by providing a more representative sample ofconditions on different days (e.g., days on which atmospheric inversions occurordon'toccur); (3) The ICF study does not report results forthe more realistic Scenario 4 for propylene. Itwould have been useful to havethe results forthis more realistic scenario for propylene. It is difficultto make any substantial conclusions regarding propylene without having this scenario assessed. (4) Specific hydrocarbon refrigerants were not separately modeled. Rather, the results ofthe ICF (2014) study apply onlyto the SUM ofall hydrocarbon refrigerants, or the SUM ofthose hydrocarbon refrigerants containing a specific hydrocarbon. It does not seem reasonable to regulate a single refrigerant based on a whole family of refrigerants. Each refrigerant should be assessed separately bythe Agency. Consequently, it is my opinion the portion ofthe proposed rule pertaining to the results and implications ofthe CMAQ modeling is arbitrary and capricious, does not represent good science, and cannot reasonably be used to regulate one individual refrigerantfor any urban location.