Radon Measurement and Mitigation
Radon is a naturally occurring radioactive gas without color, odor, or taste that comes from the natural breakdown of uranium in soil, rocks, and water. Dickinson College sits on a geologic formation called the Reading Prong, which underlies southeastern Pennsylvania and parts of New Jersey, and has been identified as containing naturally occurring uranium with the potential for infiltration to the air.
Although there is no legal requirement to control exposure to radon or any legal standard for radon exposure, to promote healthy working and living conditions for its employees and students, Dickinson College has developed the following campus wide radon measurement and mitigation plan.
The testing protocol follows the U.S. Environmental Protection Agency (EPA) publication, Radon Measurement in Schools. Specifically, areas to be considered for testing are identified as spaces located below grade, spaces located over a crawl space, and spaces that come into direct contact with the ground. In this instance, such areas might include, but not be limited to: offices, student rooms, classrooms, laundry areas, and social spaces that are occupied for more than 2 hours per week. Areas for testing would not typically include stairways, hallways, storage rooms, closets, equipment rooms, kitchens, bathrooms, or buildings undergoing renovations.
The testing implementation strategy is partially based on our estimation of the potential amount of time a category of individual (student, employee) might typically spend in a designated space during their years enrolled as a student or employed by the College. Calculations based on these criteria results in an implementation plan divided into 2 testing phases: phase 1 -- office space and living space/bedrooms, phase 2 -- public spaces. Phase 1 will take place during the winter of 2012--2013, and phase 2 will take place during the winter of 2013--2014.
Building occupants will be provided guidelines for testing including requests that charcoal canisters that measure the radon not be disturbed. Implemented mitigation will be communicated to building occupants. Where mitigation systems are installed, radon testing every 5 yerars as a periodic check of mitigation systems is envisioned.
- If testing confirms the presence of radon levels greater than 4 pCi/L, plans will be made to mitigate radon levels in the building, with a general target goal being 4 pCi/L or less.
- Whenever mitigation is performed, follow-up testing with charcoal canisters will be performed to determine whether the mitigation achieved the general target goal, in the range of 4 pCi/L or less.
Environmental Protection Agency (EPA) guidelines recommend considering mitigation when indoor radon levels are greater than 4 pCi/L.
If mitigation is implemented, the College will use a certified radon mitigator to design and oversee the work. Mitigation techniques may include sealing cracks in building foundations or installing sub-slab ventilation systems to vent the radon gas.
Frequently Asked Questions
What is radon?
Radon is a naturally occurring radioactive gas that comes from the natural breakdown of uranium in soil, rocks, and water. Levels of radon are common in the air we breathe every day.
Why is the College testing for radon?
Though radon is common in the everyday living environment, the US Environmental Protection Agency has set guidelines that recommend limiting long term residential exposure levels to 4 picoCuries/liter (pCi/L) of air because of health risks associated with long-term exposure to high radon levels.
What factors influence radon levels in a building?
A large number of factors influence radon concentrations:
- the amount of uranium in the geological structures underlying the soil and how close the underlying structures are to the soil surface;
- the concentration of radon in the soil and the permeability of the soil;
- time of day (radon concentrations often reach a peak in the middle of the night because of temperature differences between inside and outside) and the season;
- weather conditions, such as temperature, wind speed and direction, and humidity;
- building structure (slab construction, presence of crawl spaces)
- ventilation conditions (areas where doors and windowns may not be opened regularly)
- type, operation, and maintenance of the heating, ventilation, and air conditioning (HVAC) system
How does the College test for radon?
The EPA guidelines for Radon Measurement in Schools provide a general basis for testing at Dickinson College. There are a variety of tests available to measure the level of radon present, and there are advantages and disadvantages to each type of test. One of the most widely available is a short-term test that utilizes charcoal canisters. Charcoal canisters are typically placed for 3--5 days and then collected and analyzed. Charcoal testing is good for quick assessments of the radon present during the time the canisters were present, but it only presents a "snapshot" of the conditions during those 3--5 days.
What does the sampling canister look like?
The sampling canisters are small metal canisters, with a metal screen covering activated charcoal. The canister is about 2--3" in diameter and has a strip of tape around its edge to seal the canister lid before and after testing to keep it airtight.
Do the air sampling canisters pose any health risk?
No. The charcoal which the canisters contain is not hazardous, and the charcoal does not re-emit the radon after the radon is adsorbed.
Where can I expect to see the sampling canisters?
A sampling canister will generally be placed in rooms, regularly occupied for more than 2 hours per week that are in contact with the ground or are above closed crawl spaces.
Why is testing only being performed at the lower levels of a building?
EPA studies indicate that radon levels on upper floors are not likely to exceed the levels found in ground contact rooms. Testing rooms in contact with the ground is generally regarded as sufficient to determine if radon is a problem in a building.
Why isn't the College testing every space that could potentially be occupied?
The potential health risk from exposure is proportional to both the radon concentration and the amount of time spent in an area. This means that, if only a short time is spent in an area which has significantly elevated radon levels, the total exposure is not likely to exceed the risk of spending a long time in an area with an only slightly elevated level. In designing its protocol for sampling in schools, the EPA recognized that measurement and mitigation resources should be concentrated on areas in which occupancy is at least 2 hours per week or more.
If there are elevated radon levels in the room next to mine, does that mean there will be elevated levels in my room?
Not necessarily. Indoor radon levels may vary from room to room, depending on various factors that might include: the pattern of airflow in the building; the location of features such as crawlspaces and foundation cracks; and the depth of soil and rock under different parts of the building. It is not possible to make a reliable prediction from one room to the next. The way to determine radon levels throughout a building is to test the protocol identified areas.
If there are elevated radon levels in the building next to mine, does that mean there will be elevated levels in my building?
Not necessarily. Indoor radon levels may vary from building to building, so it is not possible to make a reliable prediction from one building to the next. Guidance and experience suggessts you should not rely on radon test results taken in other buildings nearby to estimate the radon level in your building. The way to determine radon levels in a given building is to test.
What is a picoCurie?
The quantity of radioactivity present is expressed in a unit called the Curie. One Curie is equivalent to 37 billion radioactive atoms disintegrating per second. However, the amount of radioactive atoms disintegrating per second as a result of the presence of radon in air is only a very small fraction of a Curie. In fact, the most convenient unit to express the amount of radioactivity present in air is the picoCurie, which is 1 trillionth of a Curie. For example, if an area has a radon level of 1 pCi/L of air this is equivalent to 0.037 radioactive atoms disintegrating per second in that liter of air.
Does radon cause headaches, eye irritation, or sick-building syndrome?
Is radon in water a problem?
The primary entry route of radon in buildings is through the soil. However, radon can also enter through the water suupply. It can then be released into the air while using water. Radon in water is not generally considered to be a problem for buildings serviced by a public water supply, as public water supplies must be tested per EPA requirements. Dickinson College water comes from a public water supply.
Are building materials likely to contain or emit radon?
Radon emission from soil gas and its subsequent entry through the building foundation has been identified as the major source of radon in schools. Some building products may emit radon, but EPA studies indicate these concentrations are likely to be insignificant.
What resources are available for additional information?
A Citizen's Guide to Radon (EPA)
Radon Measurement in Schools (EPA)
If my question is not answered here, who can I contact at the College?
Questions should be directed to William J. Shoemaker, Director Environmental Health & Safety at 717-245-1495.