What's New?
.	HPS and CRCPD Proclaim 8-14 November 2009 as National Radiation Protection Professionals Week
.	November Newsletter
.	NRC Academic Program Nuclear Education Grants, FY2010, Now Accepting Applications
.	November ORS
.	November Journal
.	EPA's STAR Graduate and GRO Undergraduate Fellowship Funding Now Accepting Applications

Upcoming Events
.	2010 HPS Midyear Topical Meeting Radiation Risk Communication to the Public 24-27 January 2010 Albuquerque, NM
.	2010 HPS Professional Development School Radiation Risk Communication: Issues and Solutions 27-29 January 2010 Albuquerque, NM

07 November 2009

Answer to Question #980 Submitted to "Ask the Experts"

Category: Radon

The following question was answered by an expert in the appropriate field:

I am trying to find data on isotopic contributions to gross alpha and beta activities measured on air particulates (air filters). By standard practice the sealed filters are allowed to sit for five days to allow the short-lived progeny of ²²²Rn and ²²⁰Rn to decay. Any information, data, and especially citable references would be appreciated.

I do not have any references for the question asked—however, I can say that five days is a reasonable time period for allowing ²²⁰Rn progeny to decay. Robert Coleman Oak Ridge National Laboratory

Answer posted on 3 July 2001. The information and material posted on this Web site is intended as general reference information only. Specific facts and circumstances may alter the concepts and applications of materials and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice specific to whatever facts and circumstances are presented in any given situation. Answers are correct at the time they are posted on the Web site. Be advised that over time, some requirements could change, new data could be made available, or Internet links could change. For answers that have been posted for several months or longer, please check the current status of the posted information prior to using the responses for specific applications.