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Lesson 4. What are the units for measuring radon?. Radioactivity units Picocuries (pCi). Measures Activity (radioactive decays/second) 1 picocurie (pCi) = 0.037 decays/second = 1 decay/27 seconds = 2.22 decays/minute. Radon units Picocuries/Liter ( pCi/L). Measures
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Lesson 4 What are the units for measuring radon?
Radioactivity unitsPicocuries (pCi) Measures • Activity (radioactive decays/second) • 1 picocurie (pCi) = 0.037 decays/second = 1 decay/27 seconds = 2.22 decays/minute
Radon unitsPicocuries/Liter (pCi/L) Measures • Activity (decays/minute) per volume (one liter of air) • 1 pCi/L = 2.22 decays per minute per liter of air
EPA action levelPicocuries/liter 4 pCi/L = 4 x 2.22 decays/minute/liter = 8.88 decays/minute/liter
International System (SI)Radioactivity units 1 becquerel (Bq) = 1 decay/second = 27 pCi 1 pCi = 0.037 decays/second = 0.037 Bq Henri Becquerel, discovered radioactivity in 1896
International System (SI)Radon units 1 pCi/L = 37 Bq/m3
EPA action level International System (SI) 4pCi/L = 4 x 37 Bq/m3 = 148 Bq/m3
Measure alpha radiation emitted by short-lived RDPs Measuring radon decay products (RDPs) Polonium-218 Lead-214 Bismuth-214 Polonium-214
1 WL = Concentration of RDPs produced from one liter of air that contains 100 pCi/L of radon = Amount of short-lived RDPs that exists at a single moment if a container is kept at a constant 100 pCi/L Measuring RDPsWorking level (WL)
Working levelEPA action level 4 pCi/L = 0.02 WL
EPA action level Summary • 4 pCi/L • 148 Bq/m3 • 0.02 WL
Characteristics of radon decay products (RDPs) • Solid particles • Electrically charged • React chemically
Factors that affect radon and RDP concentrations • Air circulation • Air moving within a room • Ventilation • Fresh air entering a room • Air filters • Particles suspended in the air • Dust • Smoke • Aerosols Some RDPs plated out
Secular (eventual) equilibrium • Takes 3-4 hours • At secular equilibrium, 1 WL = 100 pCi/L Radon decay products Radon Radon
Picocuries and becquerels; secular equilibrium. Radon decaying has made my brain cells go numb. But I do understand: breathing radon’s not healthy, So I’ll master these concepts, though they won’t make me wealthy. A home inspector’s lament and pledge Convert all these measurements? Curse that uranium! I’m working at levels that hurt my poor cranium. I’ll learn proper techniques, use the right protocol, To help prevent cancer: that’s the goal of my role.
SummaryEPA action level 4 pCi/L = 148 Bq/m3 =0.02 WL 4 4 pCi/L = 148 Bq/m3 =0.02 WL
SummaryFactors affecting measurement • Air circulation • Ventilation • Air filters • Particles in the air Importance Factors affect conditions for testing a home