Abstracts Law

An experimental comparison of various nuclei counters

by Joel William Mansell

"A series of simultaneous nuclei concentration measurements, with four different nuclei counters, have been made. these counters were a Pollak and a Gardner counter supplied by Mr. Paul Allee of the Environmental Science Services Administration, Boulder, Colorado, and a Pollak and a G.E. counter supplied; by Mr. Norman White of the National Center for Air Pollution Control, Cincinnati, Ohio. In the absence of any knowledge of the absolute concentrations in the samples, the data for each of the individual counters have been compared to the averages computed from all four counters. The results of these comparisons indicate the following: (1) differences between individual counters sampling the same air are often as high as 50% and in some cases exceed 100%, (2) the variability in the response of individual counters is as low as ł10% for the G.E. and as high as ł20% in the case of the Gardner, (3) the agreement between the two Pollak counters is not appreciably better than the agreement between these counters and the G.E. or Gardner counter, (4) the percentage difference between counters increase as nuclei concentrations increase. A possible explanation of the differences in counter response is given and recent modification to the U.M.R. absolute nucleus counter are discussed" – Abstract, p. ii.