title: Increased environmental gamma-ray dose rate during precipitation: a strong correlation with contributing air mass.
abstract: It has long been observed that the environmental gamma-ray dose rate increases noticeably during precipitation intervals. This increase, due to the presence of radon progeny in the rain droplets (or snow flakes), can affect the reliability of the monitoring of artificial radioactivity and long term estimates of exposure to ambient natural radionuclides in surveillance network. Predicting the amplitude of the dose increase has been shown to be surprisingly challenging. In this work, standard air mass back trajectory analysis is used to show that the amplitude of the increase can be quantitatively linked to the history of the air mass where the precipitation is occurring. Furthermore, we show how back trajectory analysis, environmental gamma and rain data can be used to obtain estimations of relative radon emanation rates for locations far from the actual point of detection.
authors.affiliation: Radiation Protection Bureau, Health Canada, 775 Brookfield Road, K1A 1C1, Ottawa, Ontario, Canada. jeanfrancois_mercier@hc-sc.gc.ca
authors.forename: J-F
authors.initials: JF
authors.lastname: Mercier
authors.forename: B L
authors.initials: BL
authors.lastname: Tracy
authors.forename: R
authors.initials: R
authors.lastname: d'Amours
authors.forename: F
authors.initials: F
authors.lastname: Chagnon
authors.forename: I
authors.initials: I
authors.lastname: Hoffman
authors.forename: E P
authors.initials: EP
authors.lastname: Korpach
authors.forename: S
authors.initials: S
authors.lastname: Johnson
authors.forename: R K
authors.initials: RK
authors.lastname: Ungar
mesh_terms: D004784:Environmental Monitoring; D005720:Gamma Rays; D011834:Radiation Monitoring / Q000379:methods*; D017687:Radon Daughters / Q000032:analysis; D011891:Rain
chemical_list: D017687:Radon Daughters