Presentation on theme: "Take in a Deep Breath! Blow It Out!!! Typical Annual Radiation Exposure... 360 mrem/yr."— Presentation transcript:
Take in a Deep Breath!
Blow It Out!!!
Typical Annual Radiation Exposure mrem/yr
Annual Exposure from Common Activities RADON Courtesy of David C Howell, Radiation Safety Officer-Wake Forest University-Baptist Medical Center Diet Smoking Medical US Flight Nuclear Power 40 mrem 5000 mrem 200 mrem 53 mrem 5 mrem/trip <0.05 mrem
Annual Exposure from Common Activities RADON Courtesy of David C Howell, Radiation Safety Officer-Wake Forest University-Baptist Medical Center Smoking Medical Nuclear Power 5000 mrem 200 mrem 53 mrem <0.05 mrem
Radon is a naturally occurring gas emitted from the earth.
Radon is a colorless, odorless, tasteless, inert, radioactive gas.
It is a naturally occurring gas that enters buildings, homes and the environment from the surrounding soil. URANIUM RADIUM RADON GAS It comes from the decay of Uranium which decays into Radium and then into Radon gas.
Therefore, ALL homes have some level of radon... Radon is also found in the outdoor air. Radon is produced in most soil or rock.
Uranium Decay Chain Uranium Half-life: 5 billion yrs Radium Half-life: 30 seconds Radon-222: Half-life: 3.8 days Bismuth-214, polonium-218 & 214, and lead-214 Half-life: very short (less than 30 minutes)
Bismuth-214, Polonium-218 & 214, and Lead-214 Half-life: very short (less than 30 minutes) These decay products account for major portion of radiation dose received in the lungs.
Alpha Radiation ( ) Particle released when the nucleus kicks out 2neutrons and 2 protons Relatively massive Relatively slow Total charge of +2 Mass number changes by 4 and atomic number changes by 2
Beta Radiation ( ) Particle released when the nucleus changes a neutron into a proton and a beta particle Relatively small mass Relatively fast moving Total charge of -1 Atomic Mass Number remains constant P N
Gamma Radiation ( ) Pure energy. Released from the nucleus when an alpha or a beta is emitted No mass Speed of light No charge NO CHANGE
Courtesy of David C Howell, Radiation Safety Officer-Wake Forest University-Baptist Medical Center
Plastic chip from passive radon test (alpha track) Magnified only 100 times 3 months at EPA Action Level of 4 pCi/L
Radon Decay Products Radon
CARCINOGEN Radon is a known CARCINOGEN! Miner Studies Residential Studies Animal Studies
World Health Organization National Academy of Sciences BEIR International Commission on Radiological Protection National Council on Radiation Protection & Measurement Centers for Disease Control American Lung Association American Medical Association American Public Health Association U.S. Surgeon General CARCINOGEN Radon is a known CARCINOGEN!
n Highly radioactive particles (RDP’s) stick to lung tissue, where they can irradiate sensitive cells. n Radiation can alter the cells, sometimes damaging the DNA of the lung cells, thus increasing the potential for cancer. Image from:
Zone 2: Moderate Potential (2-4 pCi/L) Zone 1: Highest Potential (> 4 pCi/L) Zone 3: Low Potential (< 2 pCi/L) Radon Prevalence in NC
Air movement through soil Cracks in foundations Through well water Also through some building materials (ie. Concrete) that have the potential to contain and emit Radon. Radon entry depends on...
Strength of the radon source How effectively radon is delivered to the indoor space Ventilation rate
Exhaust Systems HVAC, house fans, etc. Thermal Stack Effect Weather Conditions Excessive rain, snow, wind
When exhaust fans remove air from a building, much of the replacement air comes from the soil underneath the building.
Source: WRRTC When indoor temperatures are higher than outdoor temperatures and the warm air rises, it is replaced with the cooler, more dense air from the outside. Some of this air moves through the soil and carries radon with it.