Hazard 8: Radiation. Healthy Home Rating System (HHRS)

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1 Hazard 8: Radiation Healthy Home Rating System (HHRS)

2 Description of the Hazard This hazard covers the threats to health caused by exposure to radiation. Radiation is the process of energy emission as waves or particles. Ionizing radiation, which includes alpha particles resulting from the decay of radon, can pass through the tissues of the body and damage DNA, causing genetic mutation. Radon is primarily airborne, but can also be found dissolved in water

3 Radon Half-life and Decay Radon has a radioactive half-life of only 3.8 days. This means that approximately every 4 days, the gas decays and halves itself. This effectively means that radon levels can change on a regular basis. A measurement taken one day would have half the measured value four days later. Radon decays into polonium-218, and eventually into lead

4 Potential for Harm The most vulnerable age group is all persons aged between 60 and 64 years who have had a lifetime exposure to radon. This is because prolonged lifetime exposure to radon has been shown to greatly increase the risk of lung cancer. The spread of health outcomes is based off lung cancer statistics

5 Health Effects Within dwellings, the main source of radon comes from the soil under the foundation of the house. Sometimes it enters the home through well water as well. Radon is an odorless, tasteless and invisible gas that is a result of the decay of naturally occurring uranium in soil and water. The gas can infiltrate the household through cracks and gaps in the foundation, most often in the basement. Risk of radon poisoning generally varies by area, as some areas have much higher natural radon occurrence than others. The most prevalent risk from radon exposure is lung cancer, seeing as the gas is airborne and enters the body through inhalation

6 Relevant Matters Affecting Likelihood and Harm Outcome 1. Timber ground floor Ground floor of suspended timber construction particularly if without adequate sub-floor ventilation. 2. Disrepair to old floor Holed, cracked or other disrepair to a solid ground floor. 3. Lack of DPM Lack of or defective damp proof membrane to solid floor. 4. Private water supply Particularly if from a borehole or well. 5. Ventilation rates High upper-level ventilation rates. 6. Open fires Use of open fires and sold-fuel-effect open fires, without additional through the wall ventilation. Floor disrepair Timber ground floor Damp proof membrane beneath floor Information taken from HUD Guidance Manual on HHSRS

7 Radon Zone Map - National Radon levels vary on both national, state and county levels, as seen in this map. Zone 1 counties (red) have a predicted average indoor radon level greater than 4 pci/l. Zone 2 counties (orange) have predicted levels of 2 to 4 pci/l. Zone 3 counties (yellow) have predicted levels of less than 2 pci/l. Information taken from HUD Guidance 2015 Manual on HHSRS 7

8 Hazard Prevalence in HHRS Study Sites Radon levels vary by state and county. The national average for indoor radon concentration is 1.3 pci/l. EPA s current action level sits at 4 pci/l. In Wayne County, MI, the average indoor radon level is 2.5 pci/l. 61% of households have results under 2 pci/l, 22% of households have results between 2 and 2.9 pci/l, and 17% are above the 4 pci/l action level. In Alameda County, CA, the average indoor radon level is 1 pci/l. 91% of households have results under 2 pci/l, 5% of households have results between 2 and 2.9 pci/l, and 4% are above the 4 pci/l action level. In Guilford County, NC, the average indoor radon level is 1.6 pci/l. 75% of households have results under 2 pci/l, 13% of households have results between 2 and 2.9 pci/l, and 11% are above the 4 pci/l action level. In Douglas County, Nebraska, the average indoor radon level is 1.3 pci/l

9 Outcome Data: National Radon is the second leading cause of lung cancer in the U.S., and is associated with 15,000 to 22,000 lung cancer deaths each year. It is also the number one cause of lung cancer in non-smokers

10 Associated Health Outcomes Lifetime exposure to radon has shown to cause a greatly increased risk of lung cancer. There is also weaker epidemiological evidence of radon affecting other organs through ingestion and skin contact, resulting in malignancies such as leukemia and skin cancer. Radon that has dissolved in water can be ingested, resulting in the organs of the gastrointestinal tract receiving the largest dose

11 Healthy Home Rating System Project Leadership Lyke Thompson Director CUS/WSU (313) Allyson Lindsey Research Assistant CUS/WSU (313) David Ormandy Professorial Fellow University of Warwick +44 (0)