A S TRUST & 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 L Street, NW, 10th Floor 

Washington, DC 20005 

Comment by Gary Whitmyer on the CMAQ Modeling 

September 4, 2014 

As per our conference call with EPA on August 21, 2014 during which Margaret 

informed all of us 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 "Assessment of the 

Potential Impacts of Hydrocarbon Refrigerants on Ground-Level Ozone Concentrations, 

February 24, 2014". 

In this analysis, ICF modeled 4 scenarios: 

- Scenario 1: rapid replacement of all refrigerant uses with various hydrocarbon 

refrigerants; 

- Scenario 2: rapid replacement of all refrigerant uses except motor vehicle AC (MVAC) 

with hydrocarbon refrigerants; 

- Scenario 3: rapid replacement of all refrigerant uses except MVAC and chillers with 

hydrocarbon refrigerants; and 

- Scenario 4: more gradual replacement of refrigerants with hydrocarbons of various 

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 of the ICF (2014) study, a number of limitations 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 1 year (2005) of meteorological data. It is 

standard practice in ambient air modeling studies to focus on several years (typically 5 

years) of meteorological data in order to capture a broader data set to reduce the 

uncertainties in the analysis by providing a more representative sample of conditions on 

different days (e.g., days on which atmospheric inversions occur or don't occur); 

(3) The ICF study does not report results for the more realistic Scenario 4 for 

propylene. It would have been useful to have the results for this more realistic scenario 

for propylene. It is difficult to make any substantial conclusions regarding propylene 

without having this scenario assessed. 

(4) Specific hydrocarbon refrigerants were not separately modeled. Rather, the 

results of the ICF (2014) study apply only to the SUM of all hydrocarbon refrigerants, or 

the SUM of those 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 by the Agency. 

Consequently, it is my opinion the portion of the proposed rule pertaining to the results 

and implications of the CMAQ modeling is arbitrary and capricious, does not represent 

good science, and cannot reasonably be used to regulate one individual refrigerant for 

any urban location.