Atmospheric particulate mass measurement with beta attenuation mass monitor

TLDR: A two-stage on-line mass monitor with aerosol size separator (TWOMASS) employing the beta attenuation technique has been developed for monitoring of atmospheric aerosols with high time resolution as mentioned in this paper.

Abstract: A two-stage on-line mass monitor with aerosol size separator (TWOMASS) employing the beta attenuation technique has been developed for monitoring of atmospheric aerosols with high time resolution. This instrument independently analyzes the mass concentration of two particle size fractions. Coarse particles are inertially separated by impaction on filter paper. The fine particle fraction is collected on a high-efficiency glass-fiber filter. Carbon 14 is used as a source of beta particles which are detected by a silicon surface-barrier detector coupled to fast, low-noise nuclear electronics. A programmable calculator controls TWOMASS, calculates the mass concentration of each size fraction, plots, prints, and stores the data on tape. The instrument has been gravimetrically calibrated using laboratory and atmospheric aerosols. For 10-min sampling intervals, the precision of the instrument is 4 ..mu..g/m/sup 3/, and the accuracy is 11 percent. It has subsequently been field tested by sampling atmospheric aerosol over an extended period which indicates that it is capable of ambient air monitoring with a time response on the order of 10 min.