Laboratory evaluation of a recording respirable mass monitor.

A laboratory evaluation was conducted of an impaction-beta detection recording respirable mass monitor (RRMM), a prototype of the commercial RDM-301 manufactured by GCA Corporation. Areas investigated were the effect of dust concentration, size distribution, and sampling time on the accuracy and precision of the RRMM instrument when compared with personal gravimetric samplers. Results showed a good linear correlation between 1 and 20 mg/m3. However, the RRMM underestimated the gravimetric concentration when a significant mass of submicrometer particles was present. A commercial RDM-301 was also tested, and a decrease in precision was observed with decreasing concentration for a set sample time.