United States
 Environmental Protection
 Agency
Environmental Sciences Research
Laboratory
Research Triangle Park NC 2771
Research and Development
EPA-600/S8-82-015  Nov. 1982
Project  Summary

CHAVG—A  Program  for
Computing  Averages of
Hourly  Air  Pollutant
Concentrations:
User's Guide

Joseph A Catalano and Frank V. Hale III
  CHAVG is a postprocessor program
for computing running averages (aver-
ages that begin each hour and overlap)
and end-to-end averages (averages
that do not overlap) from hourly
concentration files.  Since running
averages are greater than or equal to
the  end-to-end averages, there fre-
quently may be need to analyze concen-
tration data (from measurement or
from air quality simulation models,
such as, the UNAMAP series) using
both methods of averaging. Calcula-
tions are made for selected receptors,
and these values are ranked for each of
four averaging periods plus a fifth
period selected by the user. Output
tables are generated for each averaging
period for each  type of average
selected by the user. The user's guide
describes the input, processing, and
output of the program.
  This Project Summary was de veloped
by EPA's  -Environmental Sciences
Research Laboratory. Research Triangle
Park, NC, to announce key findings of
the research project that is fully
documented in a separate report of the
same title (see Project Report ordering
information at back).

Introduction
  Although several of the air quality
simulation models in the UNAMAP
series (CRSTER, MPTER,  RAM) are
routinely capable of producing sum-
maries of highest concentrations for
end-to-end averaging periods, none
produce summaries of running averages.
For convenience, a standard routine for
providing summaries of highest running
average concentrations is made available
with information for its use.

Computer Program
  I n addition to providing the highest 1 -
hour concentrations and averages for
the length of record, highestend-to-end
averages are given for 3-, 8-, and 24-
hour averaging times and optionally for
running averages forthe same averaging
periods. An additional averaging period
may also be selected from 2-, 4-, 6-, or
12-hour averages.
  A file consisting of a period of record
of 1-hour concentrations must be
available for input to the program.
  An example problem is  provided for
use  in program understanding and
check-out. A listing of the FORTRAN
source program is included.

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       Joseph A. Catalano and Frank V. Hale III, are with Aerocomp, Inc., Costa Mesa,
         CA 92626.
       D. Bruce Turner is the EPA Project Officer (see below).
       The complete report, entitled "CHA VG—A Program for Computing A vereges of
         Hourly Air Pollutant Concentrations: User's Guide," (Order No. PB 83-107
         342; Cost: $10.00, subject to change) will be available only from:
               National Technical Information Service
               5285 Port Royal Road
               Springfield, VA 22161
               Telephone: 703-487-4650
       The EPA Project Officer can be contacted at:
               Environmental Sciences Research Laboratory
               U. S. Environmental Protection Agency
               Research Triangle Park, NC 27711
       U.S. GOVERNMENT PRINTING OFFICE:  1982—659-O17/O8S8
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300

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