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Developed by theHealthy Environments for Children
Initiative at the University of Connecticut
for the Connecticut Department of Public
Health
2006
Measuring Radon in Residential Properties
Training Program
Measuring Radon in Residential Properties
Training Program
Lesson 1
What is radon?
Slide 4-3
Characteristics of radon
• Gas• Colorless• Odorless• Tasteless• Occurs in nature• Radioactive• Harmful to human health
Slide 4-4
Simple atom
• Nucleus– Protons (+ or
positive charge)– Neutrons (no
charge)
• Electrons (- or negative charge)
Slide 4-5
Radon (Rn) atom
Atomic number = Number of protons86
Atomic mass or mass number =
Number of protons + number of neutrons
Varies
Slide 4-6
Naturally occurring radon isotopes
Number of
protons
Number of
neutrons
Atomic mass
Radon-219 86 133 219
Radon-220 86 134 220
Radon-222 86 136 222
Slide 4-7
Radiation = energy emitted as invisible • Particles• Waves• Rays
Isotopes
• May be stable or unstable• Unstable isotopes
(radioactive) decay spontaneously (change to another element) called– Decay products– Progeny – Daughters
• During decay, unstable isotopes give off radiation
Slide 4-8
Radon decay series
Radon-222
Polonium-218
Bismuth-214
Polonium-214
Lead-210
Lead-214
Slide 4-9
Radon and its decay products
Radon Decay products
Gas Solid
Chemically inactive Chemically active
No static electrical charge
Electrically charged
Primary source of cell damage leading to lung cancer
Slide 4-10
Types of radiation released
Alpha () Beta () Gamma ()
Relatively large mass
Relatively small mass
No mass
= 2 protons and 2 neutrons
= 1 electron = pure energy (electromagnetic radiation)
Electrical charge of +2
Electrical charge of -1
No electrical charge
Moves slowly Moves quickly Moves at the speed of light
Least penetrating Moderately penetrating
Most penetrating
Most damaging to human health
Slide 4-11
Radiation released in radon decay
Radon-222 +
Polonium-218 +
Bismuth-214 +
Polonium-214 +
Lead-210
Lead-214 +
Slide 4-12
Example of half-life
100.00
50.00
25.00
12.506.25 3.13 1.56 0.780
20
40
60
80
100
0 1 2 3 4 5 6 7
Number of days
Percentage of atoms
remaining
Slide 4-13
Half-lives of radon and its decay products
Radon-222 3.8 days
Polonium-218 3.1 minutes
Bismuth-214 19.7 minutes
Polonium-214 160 microseconds
Lead-210 22.6 years
Lead-214 26.8 minutes
Slide 4-14
Summary
• No color• No smell• No taste• No electrical
charge
• Gas• Radioactive• Naturally occurring• Inert• Harmful to human
health
Radon is an element with these characteristics
