November 28, 1989  
                                  
  
  
  
  
  
  
MEMORANDUM  
  
SUBJECT:  Utah PM-10 Secondary Sulfate and Nitrate Calculations  
  
FROM:     Joseph A. Tikvart, Chief  
          Source Receptor Analysis Branch (MD-14)  
  
TO:       Marius Gedgaudas, Chief  
          Compliance Section and Utah PM-10, Region VIII (8AT-AP)  
  
     In response to your request to Dean Wilson, my staff previously
concurred generally with the procedures described in your memorandum for
apportioning source culpability for observed sulfate/nitrate concentrations
in Utah and Salt Lake counties.  As they indicated, we do have some
comments/suggestions  on the details of the procedure; these are provided
below.  
  
          1.  For each of the four up/down scenarios, a number of samples  
sufficient to support a conclusion should be analyzed.  
  
          2.  Regarding the need to consider meteorological conditions
under  which each ambient sample was taken, we believe that such
considerations should include an analyis of whether the wind direction/wind
speed were such that sulfates/nitrates or their precursors could logically
have been expected to be transported from Kennecott or Salt Lake City to
the monitor.  Given that these pollutants would either have been emitted at
some height above the ground or would have had to traverse over some
moderate terrain enroute to the Provo area, you may wish to consider the
use of low level winds from radiosondes taken twice daily at the Salt Lake
City airport in such analysis.
   
          3.  For your "continental" background values, in order to avoid  
double counting, we suggest that such data be derived from samples taken  
outside of the Salt Lake/Provo area.  We understand that the National Park 
Service has a program for PM-10 sampling; some data from such sampling may 
exist for Utah or Nevada parks.  
  
          4.  My understanding, based on discussions between our staffs, is 
that Kennecott will be found to be an insignifcant contributor to ambient  
concentrations in Utah County.  However, if this turns out not to be the
case, a Kennecott source profile should be developed and the CMB analysis
should be reanalyzed for those up/down samples that involve a contribution
from Kennecott.  
    
     If you have any questions please contact Dean Wilson (FTS-629-5683) or 
Quang Nguyen (FTS-629-0832) of my staff.  
  
cc:  N. Frank  
     L. Hanley  
     Q. Nguyen  
     M. Smith  
     D. Wells