The WHO (World Health Organization) has confirmed that radon is the second leading cause of lung cancer after cigarette smoking. In fact, it's even more deadly than second-hand smoke.
Acceptable limits of radon exposure had to be recalculated when epidemidemiological studies confirmed that "relatively low radon levels (commonly found in residential buildings) were associated with lung cancer."
As such, the new acceptable maximum level of radon gas by WHO standards is 1/10th what was in 1996. This is why we are hearing more about radon in the news lately.
Yet I'm concerned about some of the information I've read. I'll explain.
Short-term Testing Not As Accurate
Filling Cracks Might Not Help Either
In homes, there is a balance of air flow between outside air and indoor air. When barometric pressures rise and fall, this can impact the movement of air flow and even change it. Because of this, my sense is that doing a short-term radon test might not provide reliable results.
Most of the time, homes tend to suck in air from the outside.
Similarly, filling cracks that are visible might actually trap radon within a home - unless you know precisely where all of the unseen cracks are and fill them as well. Furthermore, scientists and chemists believe that radon gas molecules can penetrate many types of concrete.
And we need some exchange with the outside air in a home. A completely sealed, air-tight home wouldn't be healthy (for many reasons). So radon testing should be conducted over a long period of time (3 - 12 months) and include the winter months (when windows are kept closed).
The answer lies in ensuring that radon gas from the environment gets vented back outside.
Your house might be within acceptable limits today - however in two years, it might not. (Cracks form in the foundation of homes over time and radon takes some time to accumulate).
Ultimately, I think the building codes need to be addressed to ensure a radon-removing ventilation system is in place and we need monitors (like fire and carbon monoxide alarms) to be installed in homes, day cares, schools, public buildings, and so on.
Up next is a short video presented by Health Canada about radon in homes.
Presence of Radon Gas in Your Home
Uploaded by Health Canada (only 1:28 seconds):
Radon is one of the heaviest gases so it will be present in higher concentrations in the lower areas of a home like basements, cellars, and crawl spaces. Testing an attic would not be the first place I'd look for radon.
It is colourless under most conditions. However, if it were cooled below its already extremely low freezing point of -96 F (-71 C) it turns yellow and then orange-red the colder it gets.
Now you chemistry-loving types out there know that radon is a noble gas with no valence electrons which means it's not particularly reactive. Most radon atoms are exhaled before doing any harm.
Kerry (LimeTech on flickr) / Licensed under Creative Commons Attribution 2.0 GenericHow does radon cause lung cancer then?
The decay products of radon are the problem.
Called high-energy alpha particles, they consist of microscopic, electrically charged particles of bismuth, lead, and polonium.
These chemically active particles are inhaled or they stick to airborne particles which are inhaled.
Either way, these alpha emissions continue to decay into radiation and radon progeny while they penetrate the cells lining our lungs and cause cancer.
Richard Elzey on flickr / Licensed under Creative Commons Attribution 2.0 GenericThere are maps out there which show the areas most likely to have high radon levels. These are largely based on geographic, soil, or aerial measurements.
However, radon is constantly being released from the ground everywhere.
The amount of radon released from the ground under each home, the air exchange within each home, and the integrity of each foundation can vary greatly.
So even if my home was situated on a low radon area, I'd do a long-term radon test.
And there are certain regions of Canada and the US that tend to have higher levels of radon in the ground which are worth taking a closer look at (if only for determining new building code standards).
In Canada, CBC News posted an online interactive map on June 3rd, 2014 where you can enter an address into a search field and it will provide the reported radon level in the area.
In the US, a Map of Radon Zones also includes detailed information when you click on the state name below the map. (I like this map better, since Canada appears mostly green on it).
What if Radon Levels in the Area are Low?
Remember, there's different soil under each home; airflow within or the integrity of each foundation can vary.
Problem Areas in the Home
According to the EPA (United States Environmental Protection Agency), radon enters a home in the following ways:
- Rose Webster / All rights reservedthrough cracks in concrete floors and walls
- via floor drains
- sump pump pit
- floor/wall joints (construction joints)
- pores in concrete
- weeping tile (for drainage)
- pipe fittings
- mortar joints
- spaces behind hollow walls
- open surfaces of block walls
- some building materials (rocks)
- water from wells
If Radon Levels Are High
After I searched around for credible information from the EPA and viewed dozens of videos (including DIY ones), I felt most reassured by a couple of videos by Mark Palmer, Radon Measurement and Mitigation Systems Engineer shown next.
Following the videos are notes that I took which you might also find useful.
Radon Mitigation - The Untold Story (Part 1)
Keep in Mind
- Radon contractors should have insurance: general liability, professional liablity (errors and omissions).
- They are not electricians - the fan will need power from a class 1 wiring (most contractors can handle this, but their insurance will not cover it). So, if the wiring for your mitigation system appears "complicated" I'd hire an electrician.
- Untrained home inspectors often use inexpensive devices to measure radon levels which are not kept calibrated (and are substandard, by industry standards).
Radon Mitigation - The Untold Story Part 2 (Q&A)
- Ask mitigator if s/he knows what the codes (standards) are for radon levels in your area?
- What exactly are the codes for the discharge point?
- What are the codes for the wiring?
- Will DWV pipe be used? (It is very thin, a lot of noise is transmitted through it, and it breaks easily). You don't want DWV pipe used at all (anywhere in a radon mitigation system).
- Ensure that a 3-inch or 4-inch solid PVC Schedule 40 pipe is used both outside and inside your home. (It transmits much less noise, is thicker, safer, and required to be used for most residential radon mitigation systems).
- Find out if a Rad-Tuff membrane will be used for crawl spaces and whether or not it will be glued in to create an air-tight space. (Laws and recommendations may vary from place to place).
Finally, if you live in Canada, there is a helpful 2013 guide available through Health Canada called Radon - Reduction Guide for Canadians.
Hope you are breathing easier.