U.S. Environmental Protection Agency
Office of Transportation and Air Quality

November 2001

Document Released for Public Information

"Air Conditioning Correction Factors in MOBILE6" 

Final Report     EPA420-R-01-055      (M6.AC.002)

Authors: John Koupal and Janet Kremer


ABSTRACT:

     The Office of Transportation and Air Quality, Assessment and
Standards Division announces the release of "Air Conditioning
Correction Factors in MOBILE6" for public information.  This
document EPA420-R-01-055, also known as M6.AC.002, is available
at the MOBILE6 section of the OTAQ Web Site 
(http://www.epa.gov/otaq/m6.htm).

     Revised air conditioning exhaust emission correction factors
are being proposed for MOBILE6.  The proposed factors are based
on testing of 38 vehicles at two locations, using a test
procedure meant to simulate air conditioning emission response
under extreme "real world" ambient conditions.  These factors are
meant to predict emissions which would occur during full loading
of the air conditioning system, and will be scaled down in
MOBILE6 according to ambient conditions input by the user if
appropriate. It was concluded that the data used in the
development of the proposed factors adequately represents real
world conditions, based on the results of a correlation vehicle
tested at both test sites and a full environmental chamber.  In
general, emissions were found to increase significantly with air
conditioning operation, but under some conditions HC and CO
emissions decreased. Correction factors for start driving were
also assessed.

     This version of the report supercedes the draft version,
published in March 1998.  This version incorporates comments from
external peer review of the original draft.