Not only freshness, but US authorities measure radon gas (a radioactive gas) I don’t know why we don’t look at this in Australia, perhaps because we presume we do have more ventilated houses?
Is there any evidence that these emissions are a real risk compared to natural background radiation?
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The US Environmental Protection Agency (EPA) has multiple webpages on it and minimising background exposure causing the risk of lung cancer see https://www.epa.gov/radon - I am not sure why it is not discussed in Australia.
The National Academy of Sciences BEIR VI Report (see www.epa.gov/radon/health-risk-radon#beir) has estimated that radon causes about 15,000 to 22,000 lung cancer deaths annually based on their two-preferred models. Major scientific organizations continue to believe that approximately 12% of lung cancers annually in the United States are attributable to radon,
FYI, I was first taught about silicosis causing lung damage in 1988, but finally something is being done about it in 2023!
Re-read the EPA website, they now concentrate more on radon gas coming up from the ground beneath the homes and preparing and venting the ground underneath the slab.
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Politely it’s difficult to relate to Australia. The American continent and USA has a very different geological history, soil types and environment.
Australia’s own expertise.
The amount of background radiation present depends on many factors, like the type of soil and rock present, altitude, latitude and an individual’s diet. While this can make exposure highly variable, on average, Australians are exposed to 1.7 millisievert (mSv) each year from natural sources.
That’s the total from all natural sources including Radon gas escaping from the ground.
Looking to other sources of radiation that can affect our health, ARPANSA provides some guidance in other sources. Aircrew flying 15 hrs or more per week will add approx 1.5 mSv to their annual dose doubling the accumulated total. Anyone who has had an adominal CT scans in recent years will have added 10 mSv to their accumulated dose.
While caution is always prudent, in perspective 1.7 mSv average exposure from all natural background sources in Australia is many times less than the levels considered a risk.
For radiation exposures less than 100 mSv, the scientific evidence for increased health risk is more limited. This is because the risk of developing cancer from low radiation dose is very small compared to the overall cancer rates, which makes it very difficult to measure, even with a very large study. It is plausible that health effects could occur at levels below 100 mSv.
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I am not doubting that radon is potentially harmful. What I don’t see is that the dose you get from having granite benches is a significant increase from background levels without granite benches.
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A link that may assist further understanding of Australia’s response. Awareness is emphasised as well as the assessment of lower risk. ‘Australian Radon Action Plan | ARPANSA
Relative to most other countries, the levels of radon in Australia are very low. Figure 1 indicates that mean indoor radon levels in Australia are the lowest amongst member countries of the Organisation for Economic Co-operation and Development (OECD). Therefore, on average, radon contributes less than one third of the total dose due to all sources of radiation in the Australian environment.
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Radon is natural and there is nothing that can be done to prevent it being in the air we breath.
The level as said is low in Australia compared to other countries and regions.
As it is a gas, proper ventilation would be the best mitigation, just as with other undesired gases from things like gas cooking or even burning candles.
It is somewhat contradictory that today’s energy effeciency guidelines in sealing homes to minimise airflow from inside to outside or vice versa could lead to higher than normal levels. Of all undesired gases.
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sorry, granite was from an earlier read of EPA material some years back, they seem less concerned now.
The US has gone through state by state and put varying risks for varying states, so they do not consider themselves uniform in radon gas exposure, but I will come back to that.
If we presume for a minute that radon still affects some Australian building sites and we had the same level of home sealing and radon gas as a US home. We have 8% of the US population, 8% of 15000-22000 deaths annually is 1200-1760 Australian deaths from lung cancer per year.
However, your very nice histogram from ICRP (thank you) averages Australia out at 8 and the US at about 25 Bq/m3, so generally in our large (and diverse) countries we have a third of their level. Is there a threshold somewhere above 8 but below 25, which means we have no additional lung cancer deaths? This would be in addition to any air travel and CT scans etc., but I know you are using that just as a reassuring reference? Radon comes from degradation of uranium amongst other elements, so it would be good to know what the radon levels are in our major population centres.
As to what the EPA recommends - a bed of crushed rock underneath the slab, covered with plastic with an air pipe out, before the slab is laid (and if not ventilation then some positive pressure within the house).
In Australia, the radiation you need be most concerned with comes from above. Australia is at the top of the hit parade for melanoma, basel cell and squamous cell carcinoma.
If it’s cancer risk you’re concerned with, diet, air quality, genetics and so on are the most likely issues. Radiation from granite is probably the least of your problems.
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yep sorry, I re read the EPA website and natural radiation coming up from the ground via radon gas is now their major concern. Melanomas are Australia’s nemesis but lung cancer is a big killer too!
Well the production of radon has been around ever since uranium and radium has been around. So that is before humans ever evolved.
So why the big problem now?
Humans have always died of various cancers. Still do.
I would posit that in countries like the US and Australia where they have taken steps to reduce the number of people smoking and the restriction on where smoking can occur, has reduced the lung cancer cause of death from those causes. Those due to radon would be unchanged, so would become more prominant in the stats.
Yes lung cancer amongst never-smokers would likely become a higher proportion of the deaths.
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Australia tends to look to the WHO for guidance.
The World Health Organization (WHO) estimates around 4% of lung cancer deaths worldwide are attributed to exposure to radon found in homes and workplaces (WHO, 2017). The International Atomic Energy Agency (IAEA) recommends that governments ‘establish and implement an action plan for controlling public exposure due to radon indoors’ (IAEA, 2014).
Certainly for the US EPA reason for concern in their country, given the 3x higher than world average estimate.
Australia has one of the lowest levels of background emissions of radiation from natural sources including radon. It’s less than most other nations. The ARPANSA (Australian Radiation Protection and Nuclear Safety Authority) has accepted and responded to the WHO advice. It has developed and is proceeding with an action plan 2020-2025, which I linked in a prior post.
Is the action plan in progress a well considered response, in particular when measured against the WHO advice, and the prior measurements of Australian household/workplace radiation. Are there any significant omissions in the action plan or items to discuss not covered?
As a general comment, some measurements I took with my geiger counter about 25 years ago-
Background radiation at my place (shale/weathered shale soil) was measured, a friends house built directly onto granite had slightly elevated levels in the living area, which was well ventilated. An upside down cup set onto a raw granite part of the floor to collect Radon gas for a few hours showed about twice the counts.
In comparison, the bedside alarm alarm clock with glowing (radioactive) hour markers gave vastly higher counts. It was moved away from the bedside!
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Some interesting excerpts from the ARPANSA report:
"In Australia, most remediation of elevated radon levels will comprise increasing ventilation in the building or workplace. However, there will be some cases where this is not possible or cost-effective. In such cases, a radiation protection specialist will need to work with the management of the workplace or building to develop specific strategies to minimise radon exposure. As community awareness increases and if there is a need control radon exposure, then regulatory authorities responsible for radiation protection will need to work with the radiation protection community to increase the number of services that can provide advice on radon exposure. By working with Safe Work Australia, ARPANSA can support the development of national uniform advice and industry-specific guidance on radon mitigation.
Through the development of a radon potential map, ARPANSA can display radon zones in Australia to identify areas with potential for elevated indoor radon levels in homes and workplaces. The map is intended to help governments and other organisations target risk reduction advice and guidance. Radon potential maps are developed using a combination of data on indoor radon measurements, geology, aerial radioactivity and other geological information.
and
With the advent of widespread air-conditioning, Australian building design is now favouring energy efficiency. A significant part of the efficiency gained is produced by restricting the exchange between the building and the air outside. This reduction in air exchange could lead to elevated levels of indoor radon in new buildings, particularly in those areas where the geology produces greater amounts of radon.
ARPANSA is committed to communicating with local governments in areas with high radon potential. This will alert local governments that new housing which aims to minimise air exchange to achieve energy efficiency may inadvertently elevate indoor radon levels.
and
ARPANSA will publish an updated radon potential map of Australia, incorporating geological information, in 2023.
A bit of background information. As noted, radon is a gas; it is a formed when radium undergoes natural nuclear disintegration. Radon per se isn’t the problem; it in turn forms an isotope of polonium which as well as being a solid is also an alpha emitter. Alpha particles are heavy particles, they have only a short range but because of their mass and charge are capable of causing cell damage, particularly to the lungs when radon is ingested.
There have been surveys done of radon incidence in Australia and it is generally quite low. ( I can’t put my hand on these at the moment, perhaps somewhere on the ARPANSA web site).
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Is this what you were referring?
Or
https://journals.sagepub.com/doi/10.1177/0146645320931983
As the world’s population ages and more of us live longer, exposure increases. As radiation effects are measured in doses, I expect it is possible that doses over a lifetime may increase risks of consequential health impacts - this is not surprising. While this may seen as somewhat frightening on face value, the same changes in health consequence risks are also likely to seen with other environmental and non-environmmental factors including genetics. It is one of the risks of living a long life and aging.
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I think it was the former. Interestingly we have quite a bit of black slate on some of our floors and the background radiation level is about 0.16 microsieverts/hr (inside the house; outside it is much less). In addition, when I grab a sample from the dust filter on the return air duct on the central heating in winter it has an elevated radiation level. I should run a gamma spectrum on it. I’m not too fussed about it all; the average background in the US is about 0.4 microsieverts/hour.
