Sd. Schery et Pt. Wasiolek, A 2-PARTICLE-SIZE MODEL AND MEASUREMENTS OF RADON PROGENY NEAR THE EARTHS SURFACE, JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 98(D12), 1993, pp. 22915-22923
Measurements of radon progeny in the attached-to-aerosol and unattache
d-to-aerosol states were made in central New Mexico. Simultaneous meas
urements of attached and unattached progeny at 0.2 and 2 m were carrie
d out over a range of meteorological and terrain conditions. The ratio
of the average progeny concentrations at 2.2 to 0.2 m was 1.06 for to
tal progeny and 1.35 for unattached progeny, indicating a net downward
flux, with the unattached progeny dominating removal to the Earth's s
urface. Progeny/parent activity ratios greater than 1 were clearly det
ected (for example, at 0.2 m, the average Pb-214/Po-218 ratio was 1.43
+/- 0.10), providing partial support for some previous observations.
A two-particle-size model for radon progeny is able to account for the
observed gradients, progeny/parent activity ratios greater than 1, an
d some trends in the experimental measurements as a function of meteor
ological conditions.