Re: Filter Collection Efficiency for Personal Air Monitor (PAM/Lapel)

["Otto G. Raabe" <ograabe@ucdavis.edu>]

February 24, 1999
Davis, CA

Filter efficiency depends on face velocity (flow rate per unit area) and
particle size. All filters have a minimum efficiency for particles about
0.3 micrometer in physical or aerodynamic diameter. Smaller particle and
larger particles are more efficiently collected as discussed in Chapter 7
of INTERNAL RADIATION DOSIMETRY (1994, Medical Physics Publishing Co.
Madison, WI). This is the reason filter testing usually utilizes only
particle near 0.3 micrometer in physical diameter.

For some specifics consider the following references:

Lockhart, L.B, Jr., Patterson, R.L., Jr., and Anderson, W.L. (1964).
Characteristics of Air Filter Media used for Monitoring Airborne
Radioactivity, NRL Report 6054, U.S. Naval Research Laboratory, Washington,
DC.
 
Smith, W.J. and Suprenant, N.F. (1953). Properties of Various Filtering
Media for Atmospheric Dust Sampling, Proceedings of the American Society
for Testing Materials, 53:1122-1135.

"Sampling aerosols by filtration" in Air Sampling Instruments (1989 or more
recent edition), American Conference of Governmental Industrial Hygienists,
Cincinnati, OH.

Otto


		*****************************************************
		Prof. Otto G. Raabe, Ph.D., CHP
              Institute of Toxicology & Environmental Health (ITEH)
		     (Street address: Old Davis Road)
		University of California, Davis, CA 95616
		Phone: 530-752-7754  FAX: 530-758-6140
		E-mail ograabe@ucdavis.edu
              *****************************************************
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