An Automated, Semicontinuous System for Measuring Indoor Radon Progeny Activity-Weighted Size Distributions,d_p: 0.5–500 nm

Abstract

A system for the detection and measurement of indoor radon progeny activity-weighted size distributions (particle size, d, > 0.5 nm) and concentration levels has been developed. The system is microcomputer-controlled and involves a combination of multiple wire screen (graded screen array) sampler-detector units operated in parallel. Determining the radioactivity associated with the aerosol sampled in these units permits semicontinuous measurement of the radon progeny activity-weighted size distributions and concentration levels. This study presents details of the system and describes various stages in its development including prototype design, experimental characterization in a radon-aerosol chamber, and numerical studies for optimization of the design and operating parameters. Re-, sults of field measurements in a residential environment are presented to illustrate the resolution, sensitivity, and capabilities of the measurement system.

Dose Conversion Factor for Radon Concentration in Indoor Environments Using A New Equation for the F-fP Correlation

“…Due to geometrical differences, the flow rate was approximately 1 m3 h-' for the first system and 0.48 m3 h-' for the second in order to obtain a face velocity of 24.7 cm SKI, which give a 50% collection efficiency with a cut-off diameter of about 4 nm. Such a sampler detector unit has been described by Ramamurthi and Hopke (1991).…”

World History Of Radon Research And Measurement From The Early 1900's To Today

“…Their resolution above 500 nm, is poor. The MOUDI system [61] measures sizes between 50-5000 nm. Since it does not provide information on the ultra-fine particles that are <50 nm, a graded screen array system is simultaneously used to complement the MOUDI data and cover the whole range from 0.5-5000 nm.…”

Evaluation of the Effectiveness of Several Air Cleaners for Reducing the Hazard from Indoor Radon Progeny

“…The sampled air is drawn through a Millipore filter (0.8 pm, Type AA). Complete details of the sampler are provided by Ramamurthi and Hopke (1991).…”

“…The activity weighted size distribution was measured with the automated, semicontinuous graded screen array (ASC-GSA) described by Ramamurthi (1989) and Ramamurthi and Hopke (1991). The ASC-GSA measurement system involves the use of combination of six samplerdetector units operated in parallel.…”