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

November 2001

Document Released for Public Information

"Air Conditioning Activity Effects in MOBILE6" 

Final Report     EPA420-R-01-054      (M6.AC.001)

Author: John Koupal


ABSTRACT:

     The Office of Transportation and Air Quality, Assessment and
Standards Division announces the release of "Air Conditioning
Activity Effects in MOBILE6" for public information.  This
document EPA420-R-01-054, also known as M6.AC.001, is available
at the MOBILE6 section of the OTAQ Web Site 
(http://www.epa.gov/otaq/m6.htm).

     MOBILE6 includes revised estimates of exhaust emissions
resulting from air conditioning operation.  This will require air
conditioning behavior and the resultant emission levels to be
predicted over a wide range of ambient conditions.  Test data
used to develop these factors were gathered under conditions
meant to represent a single extreme set of conditions.  This
report addresses EPA's methodology for applying the "extreme"
data over the broader range of ambient conditions in which air
conditioner operation occurs in-use.  Using air conditioning
activity data collected in Phoenix, a methodology has been
developed which relates temperature and humidity levels to air
conditioner load using a combined measure known as the heat
index.  This methodology also incorporates some solar load impact
and will allow adjustments for cloud cover if desired by the
user.  Estimates have also been developed for the fraction of
vehicles equipped with air conditioning systems, and of those,
the fraction of malfunctioning systems. 

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