Removal of radon daughters from indoor air
The internal radiological exposure of the general population is largely due to the airborne daughter products of radon and thoron, which are found in two states, attached to aerosols or unattached, of which the latter species according to several dose models have the highest radiological dose efficiency of the two. The radon daughters may be removed from indoor air by a series of processes like ventilation, filtration, plateout, and electrostatic deposition. Ventilation (with radon-free air) is, on the one hand, a very effective measure, but usually involves introduction of colder air, in variance with energy-saving efforts. Internal filtration will not affect the radon concentration but may reduce the level of daughter activities, roughly inversely proportional to the filtration rate. At the same time, however, filtration may also change the aerosol distribution and concentration of the air and, consequently, the partitioning of the radon daughters between the attached and unattached state. This, in turn, influences the rate of deposition of radon daughters both by diffusional plateout and as an effect of an electric field. Experiments are reported demonstrating reductions in the airborne potential alpha energy by factors of 4 to 5 by use of filtration rates of 3-4 times per hour. In case of low aerosol concentrations, however, the corresponding reduction in radiological dose to critical parts of the respiratory tract may be much smaller, due to the shift toward higher fractions of the radon daughters being in the unattached state caused by the filtration. The possibility of using electrostatic deposition of radon daughters is also discussed.
- Research Organization:
- Lab. of Applied Physics J., Technical Univ. of Denmark, 2800 Lyngby
- OSTI ID:
- 5654932
- Report Number(s):
- CONF-850606-
- Journal Information:
- ASHRAE Trans.; (United States), Journal Name: ASHRAE Trans.; (United States) Vol. 91:2B; ISSN ASHTA
- Country of Publication:
- United States
- Language:
- English
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AEROSOLS
AIR
AIR POLLUTION
AIR QUALITY
ALPHA DECAY RADIOISOTOPES
ALPHA DOSIMETRY
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BUILDINGS
COLLOIDS
DAUGHTER PRODUCTS
DIFFUSION
DISPERSIONS
DISTRIBUTION
DOSE RATES
DOSES
DOSIMETRY
ECOLOGICAL CONCENTRATION
ELECTRIC FIELDS
ELECTROSTATIC PRECIPITATORS
ELEMENTS
ENVIRONMENTAL QUALITY
ENVIRONMENTAL TRANSPORT
EQUIPMENT
EVEN-EVEN NUCLEI
FILTRATION
FLUIDS
GASES
HEAVY NUCLEI
INDOOR AIR POLLUTION
INHALATION
INTAKE
ISOTOPES
MASS TRANSFER
NONMETALS
NUCLEI
OCCUPANTS
POLLUTION
POLLUTION CONTROL EQUIPMENT
QUANTITY RATIO
RADIATION DOSES
RADIATION EFFECTS
RADIOECOLOGICAL CONCENTRATION
RADIOINDUCTION
RADIOISOTOPES
RADIONUCLIDE MIGRATION
RADON
RADON 220
RADON ISOTOPES
RARE GASES
REMOVAL
RESPIRATORY SYSTEM
SECONDS LIVING RADIOISOTOPES
SEPARATION PROCESSES
SOLS
SPATIAL DISTRIBUTION
VENTILATION