Talk:Radon/Archive 1

NFPA 704
*safety square*
NFPA 704; safety square
	4 0 0

This is an archive of past discussions about Radon. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

Archive 1

Archive 2

Health effects content gone

Seems I missed a bad edit in an earlier revert. Marked for split-off anyway, I'm not going to re-include the section, but please also consider this content on the health effects of environmental radon. Femto 13:34, 24 February 2006 (UTC)

Spas

Is it really true that there is no evidence behind healhyness of radon spas? I think that the mechanism is somehow also known as activation of DNA repair mechanisms and maybe further immunisation.

Here http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10952746&dopt=Abstract is a study comparing carbon dioxide and radon spas versus artificial carbon dioxide baths alone in patients with rheumatoid arthritis, "CONCLUSION: Marked short-term improvements in both groups at the end of treatment may have masked potential specific therapeutic effects of radon baths. However, after 6 months of follow-up the effects were lasting only in patients of the radon arm. This suggests that this component of the rehabilitative intervention can induce beneficial long-term effects."

regards, tygr007

Duplicate content

There seem to be two chapters, with duplicate content, regarding the spas. It is explained in both Applications and Radon therapy sections. Perhaps they should be merged somehow. --Bisqwit 10:43, 22 August 2006 (UTC)

Radon in tumor removal

Uh guys, I think I screwed up when adding that part about removing tumors. Could someone please verify it? Starhood` 21:53, 27 September 2006 (UTC)

Cite Web

Can you people please use the {{Cite web}} template for the references? It will look neater.74.116.113.241 21:38, 3 April 2007 (UTC)

History

The Marshalls hat a closer look at the original articles from Drn and Rutherford on the Radium emanation, and they conclude that Dorn only did the same experiments already done by Rutherford in 1900 (citing his article on the gas from thorium) without claiming the gas being a new element. The Book of Rutherford from 1906 is the first source for the phrase: radium emanation and the doing further rearch gaining the insight that the emanation of thorium and that of radium are gases are different, but both from the newly discovered group of noble gases. The credit for molar mass and spectrum should go to Ramsay and Gray like it is done in most papers.

James L. Marshall, Virginia R. Marshall (2003). "ERNEST RUTHERFORD, THE "TRUE DISCOVERER" OF RADON". Bull. Hist. Chem. 28 (2): 76–83.
E. Rutherford (1900). "A Radio-active Substance Emitted from Thorium Compounds". Philos. Mag. 49: 1–14.
Rutherford, Ernest (1906). Radioactive transformations chapter: The Radium Emanation. New Haven: Yale University Press. pp. 70–94.
E. Dorn (1900). "Die von radioaktiven Substanzen ausgesandte Emanation". Abhandlungen der Naturforschenden Gesellschaft (Halle). 23: 1–15.
W. Ramsay and R. W. Gray (1910). "La densité de l'emanation du radium". C.R. Hebd. Séances Acad. Sci. 151: 126–128.--Stone 20:02, 3 July 2007 (UTC)

Radon in toothpaste

There was radium in toothpaste, not radon! --Vlad Jaroslavleff 18:24, 25 March 2006 (UTC)

Yes. Someone mixed up the elements. How can you add a gas with a half-life of 4 d to things? Dr Zak 15:49, 2 May 2006 (UTC)

Quickly. 81.174.226.229 14:29, 29 October 2007 (UTC)

Lindgren

Which of the Lindgren publications is the one used!

Lindgren (1989). Environmental pollution: Reducing the effects of deadly radon gas. Journal of Indian Museums (Museums Association of India), Volume 45:61-64.
Misquitta, Neale J., Carton, Richard W., and Chyi, Lindgren L., 1989, Excessive Radon Levels

Over Underground Coal Mines, presented at the 1989 Annual GSA meeting in St. Louis, MO. --Stone (talk) 17:54, 2 February 2008 (UTC)

Trying to work on this article

So you might notice redundant&akward information appearing in several places. I plan to trim it down in the future, but if anybody wants to help he/she is welcome to. Nergaal (talk) 03:52, 13 February 2008 (UTC)

Will do - I just finished reading up on this element and will start to add more text this weekend. --mav (talk) 04:15, 14 February 2008 (UTC)

Hm. Article coverage has been brought up to snuff by others. I don't think I can add much here. Others are just as able as I am in the organization and standardization departments. See my comments at PR. --mav (talk) 01:52, 18 February 2008 (UTC)

I've been working on using accurate citation formats. You guys cook the meal, I'll set the table. :) --Cryptic C62 · Talk 11:32, 14 February 2008 (UTC)

Refs of radon compounds

I will use this references later on. Pls don't delete them. Nergaal (talk) 13:35, 14 February 2008 (UTC)

other

Nergaal (talk) 04:59, 22 February 2008 (UTC)

Possible Positive Effects of Low level Radon Exposure

A methodical ten year long case controlled study by Thompson et al. (2008)[3] of residential Radon exposure in Worcester County, Massachusetts (that included carefully placing dose monitors for one year in areas of homes where subjects spent most time) found an apparent 60% reduction in lung cancer risk amongst people exposed to low levels (0-150 Bq/m3; typically encountered in 90% of American homes) of Radon gas.[4]. This study indicates that the LNT is flawed and that there maybe a hormetic effect at low exposure levels. --Diamonddavej (talk) 17:09, 27 March 2008 (UTC)

Question about Density of the Gas

I am trying to understand what is meant by the statement that Radon is "heavy" -- does this mean that a container filled with the gas would be noticably heavier? Is Radon so dense as a gas that a solid (like a piece of wood) would actually float in it? —Preceding unsigned comment added by Jrm2007 (talk • contribs) 09:34, 27 May 2008 (UTC)

Radon is very rare and radioactive, so it is not likely that you will have enough of it to do interesting demonstrations. However, sulfur hexafluoride has about 2/3 of the density of radon (or about 5 times the density of air), and is sufficiently safe and inexpensive to do nice demonstrations such as a floating "boat" made of aluminum foil. See these videos for example: [5], [6], [7] --Itub (talk) 09:46, 27 May 2008 (UTC)

Radon produced in nuclear reactors?

"Radon, along with other noble gases krypton and xenon, is also produced during the operation of nuclear power plants. A small fraction of it leaks out of the fuel, through the cladding and into the cooling water, from which it is scavenged. It is then routed to a holding tank where it remains for a large number of half-lives. It is finally purged to the open air through a tall stack which is carefully monitored for radiation level."

I don't believe this is true - Radon has too high an atomic number for it to be a product of nuclear fission.

Can someone please provide a citation? If not, I think it should be removed. 59.167.76.11 12:02, 8 November 2007 (UTC)

Uranium is 92. Radon is 86. Seems possible, we could ask at the WP:RD. Here's some links as well [8], [9] (seems to indicate radon is present in reactors), [10]. Most of the sources I've turned up cite it as a problem with mining. Some I've found discuss 'noble gases' in general, with out singling out radon. WLU 14:38, 8 November 2007 (UTC)

I don't think radon can be formed as a fission product because the atom undergoing fission splits roughly in half. However, it is a product of radioactive decay of uranium. Whether it forms in large enough quantities during the operation of a nuclear power plant, I have no idea. This is the kind of thing that needs a citation. --Itub 13:20, 12 November 2007 (UTC)

I looked for a while and couldn't find anything beyond the above. WLU 14:29, 12 November 2007 (UTC)

Not to mention it decays to lead! There is no reason to vent it at all. So I think the entire sentence is fiction. Ariel. (talk) 09:51, 11 January 2008 (UTC)

I take it back - forgot radon emits helium when it decays, so there is that to release. Ariel. (talk) 00:34, 13 January 2008 (UTC)

In the above paragraph, and in other sources which I have read, it states that Radon is the product of the radioactive decay of Uranium, the main article state is is from the radioactive decay of Radium, is it both? Clarification please. —Preceding unsigned comment added by 66.193.204.68 (talk) 20:21, 30 May 2008 (UTC)

Radon and radium are both part of the decay chain of uranium. Uranium decays to lead in a "chain" that takes over a dozen steps, which include radon, radium, and other elements such as polonium, protactinium, etc. --Itub (talk) 09:37, 31 May 2008 (UTC)

reference for radon produced in nuclear reactors

Peterson, K. A.; Figgen, D.; Goll, E.; Stoll, H.; Dolg, M. J. Chem. Phys. 2003, 119, 11113-11123.Nergaal (talk) 00:28, 15 January 2008 (UTC)

Are you sure about that? I looked up the paper (titled "Systematically convergent basis sets with relativistic pseudopotentials. II. Small-core pseudopotentials and correlation consistent basis sets for the post-d group 16–18 elements") and it doesn't mention radon at all. --Itub (talk) 10:00, 30 January 2008 (UTC)

Re:GAN

I would have submitted this article for GAN several months ago, but I waited for someone to wikify and trim down the Hazards section. I went in detail through all the aspects of the article except that one which I found quite repetitive. I am happy that someone else is interested in the article, but pls, try to go through that section and check for repetitivness too (I find it mega boring so I can't make myself do it :| ).

Also, in the future, for any article under the scope of wikipedia:Elements, please list them on the Wikipedia:WikiProject Elements page in the announcement tab. This will attract more reviewers ;). Thanks a lot! Nergaal (talk) 19:12, 26 June 2008 (UTC)

That is a monster of a section. I will get to it now. Gary King (talk) 19:38, 26 June 2008 (UTC)

GA Review

This review is transcluded from Talk:Radon/GA2. The edit link for this section can be used to add comments to the review. GA review – see WP:WIAGA for criteria

This article is in decent shape, but it needs more work before it becomes a Good Article.

Is it reasonably well written?
A. Prose quality:
Well done.

B. MoS compliance for lead, layout, words to watch, fiction, and lists:
In the History and etymology, paragraph 3, it would be best to spell out "International Union of Pure and Applied Chemistry" and then add (IUPAC), I mean I know what it is, but how 'bout the person that reads this article. Done
Is it factually accurate and verifiable?
A. Has an appropriate reference section:

B. Citation to reliable sources where necessary:

Is there a source available for paragraph 4 in the History and etymology section? Done
Does Reference 19 cover this ---> "Following this highly publicized event, national radon safety standards were set, and radon detection and ventilation became a standard homeowner concern"? Done
Is there a source available in the Isotopes section? Done
In the Characteristics section, is there a source for this ---> "Natural radon concentrations in Earth's atmosphere are so low that radon-rich water in contact with the atmosphere will continually lose radon by volatilization. Hence, ground water has a higher concentration of 222Rn than surface water, because the radon is continuously produced by radioactive decay of 226Ra present in rocks. Likewise, the saturated zone of a soil frequently has a higher radon content than the unsaturated zone because of diffusional losses to the atmosphere"? Done
In the Precautions section, is there a source available for the first and third paragraphs? Done

C. No original research:
Is it broad in its coverage?
A. Major aspects:

B. Focused:
Is it neutral?
Fair representation without bias:
Is it stable?
No edit wars, etc:
Does it contain images to illustrate the topic?
A. Images are tagged with their copyright status, and valid fair use rationales are provided for non-free content:

B. Images are provided if possible and are relevant to the topic, and have suitable captions:
Overall:
Pass or Fail:
If the above statement can be answered, I will pass the article. Good luck with improving this article! Also, contact me if the above statements are answered.

-- ThinkBlue (Hit BLUE) 22:36, 26 June 2008 (UTC)

All done Gary King (talk) 09:51, 28 June 2008 (UTC)

Thank you to Gary K. who got the stuff I left at the talk page, because I have gone off and placed the article as GA. Congrats. ;) -- ThinkBlue (Hit BLUE) 15:56, 30 June 2008 (UTC)

Bot report : Found duplicate references !

In the last revision I edited, I found duplicate named references, i.e. references sharing the same name, but not having the same content. Please check them, as I am not able to fix them automatically :)

"EPA radon" :
- {{cite web | title =Radiation Protection: Radon | publisher =[[United States Environmental Protection Agency]] | date =November 2007 | url =http://www.epa.gov/radiation/radionuclides/radon.html | accessdate =2008-04-17 }}
- {{cite web | last =EPA | authorlink =United States Environmental Protection Agency | title =Radiation Protection: Radon | publisher =EPA | date =November 2007 | url =http://www.epa.gov/radiation/radionuclides/radon.html | accessdate =2008-04-17 }}

DumZiBoT (talk) 05:09, 8 August 2008 (UTC)

radon + earthquake

In Italy, after the last earthquake that happened in Abruzzo, Radon caused an discussion between Giampaolo Giuliani and a lot of scientist because his presunted relatioship with earthquake. (in fact, Giampaolo Giuliani made an prevision based on Radon concentration, but the prevision was wrong in date and place, respectively 2 weeks before the accident and 120km near) --87.9.254.197 (talk) 14:55, 4 May 2009 (UTC) (Marcopete87)

Article from Association_of_American_Physicians_and_Surgeons's web page

The Association_of_American_Physicians_and_Surgeons's journal, Journal of American Physicians and Surgeons. Unfortunately, this is a quack journal (according to Quackwatch) and should not be included.PDBailey (talk) 18:32, 28 April 2009 (UTC)

The article itself may be correct whatever the journal in which it was published. Just read it and use your judgment.

The paper has been published in Environmental research ISSN 0013-9351 [11] [12] in 1990
and in Transactions of the American Nuclear Society ; VOL. 73 [13] in 1995.
and in Risk Analysis [14] and Radiation Science & Health [15] in 1998.
In Pr. Cohen's page, you can see the paper was also published in 1995 in Health's physics (Test of the linear-no threshold theory ...).
He also published it (2002) a similar article in the American Roentgen Ray Society (The Cancer Risk from Low Level Radiation) [16].

The data you are so willing to erase has been quoted and commented by a member of the U.S. Nuclear Regulatory Commission, in a text published through EHP, published by the National Institute of Environmental Health Sciences.

There are probably some more, but pick your choice : one of them might have escaped the Quackwatch... Biem (talk) 06:16, 29 April 2009 (UTC)

(1)It doesn't matter how great the article is, if it is printed on a rag on my floor, it's simply not in a credible source. I will delete any Journal of American Physicians and Surgeons reference. If you want to add something from a credible source, that is a different story. PDBailey (talk) 23:11, 29 April 2009 (UTC)

The sourceS are given above. Do you have any other objection ? and if somebody wants to read the article, who cares if it's published by "a rug" ? OK, I corrected the caption accordingly, though I think this is not a cooperative attitude. Biem (talk) 11:44, 30 April 2009 (UTC)

I think you might want to read WP:SOURCE, which leeds with, "The threshold for inclusion in Wikipedia is verifiability, not truth—that is, whether readers are able to check that material added to Wikipedia has already been published by a reliable source, not whether we think it is true." Another section you might be interested in is WP:REDFLAG. PDBailey (talk) 15:31, 30 April 2009 (UTC)

So ? ... I think that there is no source problem, whatever rule you may wave, the study has been published in dozens of peer-reviewed articles, and has been thoroughly commented (including by national academies of sciences).

Nobody has ever contested the data presented by Pr. Cohen, neither the fact that there is a negative correlation where a positive one was expected. The article you just add [17] (unfortunatly, not available on-line) has been answered by Pr Cohen [18] (unfortunatly, not available on-line). So what? The criticisms usually boil down to "this is an ecological study, ecological studies are prone to confonding factor errors, so this certainly is the case". And ? ... Well, nobody knows what the unidentified factor might be. And Pr. Cohen answered that objection too: the unidentified factor has such constrained characteristics that it is altogether highly unlikely (just read the original article).

There is a debate on that case, open, unsolved, but -oddly enough?- it is not mentioned in the radon article. Maybe this is what makes you thing the claim is exceptional, so that a WP:REDFLAG should be waived? But... Actually, there are lots of references supporting negative correlation, thus a positive effects of low-dose radiations, which you will find through the radiation hormesis article. Would it be that the radon article conveys only a one-sided point of view, and ignores another one? Or takes a firm and definite position on a point that is open to debate in the scientific community?

So, please respect the neutrality of point of view policy of Wikipedia. Thanks in advance... Biem (talk) —Preceding undated comment added 18:09, 30 April 2009 (UTC).

Biem, NPOV is not about respecting all points of view, it is about respecting main stream points of view and making sure that they get the most coverage in the article. See, for example, WP:UNDUE. If you look at the link you referenced on hormesis you will see that no national level science organization endorses hormesis as a dose response and of all the consensus bodies that have written reports on the topic, only the French see any value to the pro-Hormesis research done to date. Simple put, it is an unlikely possibility for a system as complex as humans (especially with alphas), but not one that is closed completely as a possibility. This article should reflect that. PDBailey (talk) 19:18, 30 April 2009 (UTC)

This is your opinion, but not the fact. Indeed, French officials have taken position for a more open view on radiation hormesis, but they are not alone on that subject, and not positive on hormesis - they just state that the LNT theory cannot be valid at low doses, and that more research must be done. US scientific societies agree as well that LNT theory does not fit the low doses exposition datas. When major scientific academies agree on such a position, this is not "undue" any more to account for it. So ... ? Biem (talk) —Preceding undated comment added 20:26, 30 April 2009 (UTC).

I don't know how one has opinions on statements made by the bodies. The statements are what they are, it is fact. The French say:

The LNT concept can be a useful pragmatic tool for assessing rules in radioprotection for doses above 10 mSv; however since it is not based on biological concepts of our current knowledge, it should not be used without precaution for assessing by extrapolation the risks associated with low and even more so, with very low doses (< 10 mSv)[.]

While UNSCEAR reads:

Until the [...] uncertainties on low-dose response are resolved, the Committee believes that an increase in the risk of tumour induction proportionate to the radiation dose is consistent with developing knowledge and that it remains, accordingly, the most scientifically defensible approximation of low-dose response. However, a strictly linear dose response should not be expected in all circumstances.

And the BEIR VII (this is the NAS report, probably the best we are going to get), systematically blows hormesis theory after hormesis theory out of the water writing, for example, read the section titled "Adaptive Response" at this link [19]. For example, I have previously cited:

However, problems and possible artifacts of the assay system employed are also discussed. When radioresistance is observed after doses that cause some cell lethality—for example, after chronic doses that continually eliminate cells from the population—the radioresistance that emerges may be caused either (1) by some inductive phenomenon or (2) by selecting for cells that are intrinsically radioresistant. Either process 1 or process 2 could occur as the radiosensitive cells are selectively killed and thus eliminated from the population as the chronic irradiation is delivered. In the end, an adaptive or hormetic response in the population may appear to have occurred, but this would be at the expense of eliminating the sensitive or weak components in the population

And those, are quotes, not opinions. PDBailey (talk) 20:51, 30 April 2009 (UTC)

Pdbailey, you are mixing different debates.

The ongoing scientific debate is about public exposition to low-doses of radiations, and very little is known about these expositions. Some data (statistical and biological) suggest that there may be a hormesis effect, but nobody knows at which levels and to which extent, and that effect could as well be an artefact. There are two things that are about certain : (1) statistical epidemiological data will always be insufficient to provide a direct measurement of the dose-effect relationship, (2) the biological phenomenons involved in carcinogenesis are not linear, so that the LNT certainly is not the true relationship. Apart from that, make your guess...

Now, in that context, quite a number of official bodies have stated that there is no reason for the time being to abandon the LNT approach, since there is no known substitute. Nobody contests the LNT model as far as radio protection is concerned, you may add any number of quotations they will all go the same way - I leave you that point. Indeed, but that is in a very specific context : that of radio protection. Outside this context, the "pope" of LNT, the ICRP, has officially written : "the Commission judges that it is not appropriate, for the formal purposes of public health, to calculate the hypothetical number of cases of cancer that might be associated with very small radiation doses received by large numbers of people over very long periods of time."(Draft recommendations of the international commission on radiological protection, §57, [20]) In other words, OK for LNT in radioprotection in professionnal context (the one dealt with by the ICRP), but outside that context it is not appropriate (probably a polite formulation for a much stronger opinion). Another one? "However, the LNT concept does not necessarily mean that the mechanism of cancer induction is intrinsically linear. It could hold even if the underlying multi-step mechanisms act in a non-linear way. In this case it would express a certain “attenuation” of non-linearities. Favouring LNT against threshold-, hyper-, or sub-linear models for radiation-protection purposes on the one hand, but preferring one of these models (e.g. for a specific effect) because of biological considerations for scientific purposes on the other hand, does not mean a contradiction." ([21]).

Now, this is an encyclopedia, not a forum where a debate is to be reproduced. The way I understand NPOV, when there is a scientific debate, Wikipedia should not take side in that debate, but simply describe the debate itself. And not favor a conclusion as long as there is no consensus about that conclusion.

Indeed, nobody contests the Linear no-threshold model in the field of radioprotection, so that when the article states that a bunch of officials have stated in favor of that model, it is essentially right. But, it is misleading in occulting the fact that this model is supposed to be used in a very specific field, and should not be used outside that field. Failing to give this precision, it is non-neutral. But this problem belongs to the Linear no-threshold model article, not radon, and should not be discussed here.

There is indeed a scientific debate on the effect of exposition to low-doses of radiations, but as you can see, there is no article in Wikipedia on that subject. If an article was written, it should not take side in that debate, but simply describe the debate itself, and not favor a conclusion as long as there is no consensus about that conclusion - you certainly agree with that.

As for radon, as far as I know, there is no real scientific debate on that specific theme, and no definite conclusion. Some studies are being made, some conclusions are proposed, but there is nothing very specific about radon in these articles : they are just side-effects of the ongoing debate about low-doses of radiations. Personnaly, I wouldn't dare to be positive either way : what is the real effect of radon at low doses ? who knows, really... The facts are, on the one hand, a lot of people (inspired by the LNT logic) think that radon is dangerous, some advocate a public health policy about that, and some regulations are proposed to reduce radon exposition. That is factual, and should be accounted for in the article. On the other hand, there is this study of Pr. Cohen, and the results have been reproduced in some other countries by other scholars, saying that cancer rates decreases with radon exposure. That is factual as well, and should be accounted for in this article. If you add these two facts, you certainly realize that the situation is odd - well, that's OK, the real world is like that, and the article should reflect the reality. You may also be tempted to correct the article one way or the other, and tell the reader which side is the truth ? Wrong, since the question is an open one. Since there is no real debate, the Wikipedia article should not invent such a debate, and definitely not provide a conclusion where the scientific community has no consensus (the question hasen't even been considered as such, as far as I know).

My suggestion is therefore to leave the fact the way I inserted it : just mention Pr. Cohen's study and its conclusion, because that is interesting knowledge about radon, and don't try to argue whether it's right or wrong, because this is an open question. I see that you publish yourself as a statistician? Good field - my thesis was on statistical problems :) If you are interested by low-doses of radiations, and if you know some french, you may be interested in reading fr:Faibles doses d'irradiation on which I'm working, and I'd be glad to have feedback on it (maybe I'll translate it some day?).

Biem (talk) 09:46, 1 May 2009 (UTC)

Biem, you do not appear to understand NPOV, the idea is not to represent all sides or to give equal time or anything of the like. The idea is to represent a mainstream view as the view.

In light of that, I think Cohen's paper might have been interesting because it countered the finding of another methodology. However, once incurable flaws were pointed out, this study left the mainstream and is not worth metioning. I therefore recommend that we remove any mention of the Cohen paper. PDBailey (talk) 16:00, 1 May 2009 (UTC)

I would, however suggest that the case controlled study that showed a dip is more mainstream. Go look for it on the Hormesis page (Thompson et al. Health Physics, 2008). PDBailey (talk) 16:00, 1 May 2009 (UTC)

(break) Dr. Cohen's article on radon

Hi, Pdbailey,

Which incurable flaws have you seen ? As said above, the criticisms of Cohen's paper usually amounts to "this is probably some example of Ecological fallacy" - but I have never seen nothing specific ever being pointed out. On the other hand, Cohen studied in advance the effect of smoking habits, and his conclusion in health physics 1995, where he discussed the possible bias of an ecological study thike his, was after discussion (p.170) that "the existence of an unrecognized confounder factor that would resolve the discrepancy is all but incredible". It is quite unfair (and IMHO unscientific) to his study to object an ecological fallacy without taking his argument into account.

Now, the "mainstream" depends on what you are considering. If you are speaking of scientific studies of low-level radon expositions, there are not that much studies, and the kind of results obtained by Cohen and others (quoting by memory : his study, the one in Boston, one in Scandinavia, one in France, maybe some more like the one you found) are probably the mainstream as far as statistical studies are concerned ! Now, of course, these results are contrary to what common opinion thinks. So what? There is a paradigm shift taking place right now in the field of low-doses of radiations, it is quite normal that common opinion may not be in phase with the latest results.

Once again, nobody knows whether there is a hormesis effect, and its extent if it is real. Cohen's paper was meant to be a test of the LNT theory, and this result is a strong one against LNT ; he never claimed the relationship he observed is "the real law". I just like the diagram, because it makes it obvious that there is more to say about radon than a simple LNT prediction, so let us stay humble and not draw definite conclusions - that's all, but that's important.

Since you seem to have a statistical training, try to read the health physics 1995 article and see if you can point out the incurable flaw for me. Sincerely yours, Biem (talk) 17:47, 1 May 2009 (UTC)

Selection into counties is not taken into account. See the body of work by James Heckman. Doing the kind of regression he did you could find all sorts of crazy results and so the contemporary economics literature will not publish a paper unless selection is explicitly and convincingly account for, there is a regression discontinuity design, instrumental variables, or something is done to overcome potential selection. OLS is simply not adequate, and error in the RHS variables can make it very bad. On the other hand, when you have individual level data then variation is not simply by county, but it is still be home. This is still not ideal because (to give a simple example) suppose radon levels are lower in apartment buildings, and people who live in apartment buildings usually live longer because they are less likely to drive places (they live in denser areas, closer to subways and shopping). With the car accidents path to death reduced all other deaths will become more prevalent, including lung cancer and you could get an apparent hormetic effect. Again, I am not against including a pro-hormesis article, I would just rather that it was one of the more recent less easily refuted articles. PDBailey (talk) 00:04, 2 May 2009 (UTC)

Hello, Pdbailey,

As I understand it, regression discontinuity design or instrumental variables are possible bias when ecological studies are used? OK, fine, but this wasn't the purpose of the Cohen study. His objective was to test the LNT model, and under the LNT it is easily shown (mathematically) that the cancer rate should be directly proportional to the radiation exposition, confounding effect notwithstanding. If such a proportionality is not observed (and it hasn't - nobody discusses that), this means that the LNT model is invalided, and/but that's all - you can't deduce anything about a hypothetical hormesis effect. IMHO, Cohen's study is OK with respect to that conclusion (LNT is not valid for low-dose expositions), and lot of different results point to the same conclusion, hence my assertion : a paradigm shift is on its way, so let us just be careful.

If your question is "what is the real effect of low-doses expositions to radon", then the answer is - nobody knows. I don't know, you don't know, ant the scientific community doesn't know : and that can easily be proven and verified (the Wikipedia policy deals also with verification).

But we are not dealing with a scientific debate, but with the formulation of an encyclopedic article. What should we do about this article, then ?

The idea that radon is dangerous at low doses relies directly on the LNT modelisation, and scientifically speaking, these conclusions are uncertain. Cohen's study is directly related to radon concentrations, and clearly demonstrates that the LNT theory is incorrect. This is why that study is interesting for this article : it shows that the commonly-accepted conclusions are built on shaky grounds. There might be a hormetic effect with low-doses expositions, but that is not the problem. The point is simply, that the "common knowledge" in this field should not be taken for granted, and that more investigations may lead to change the presently-accepted conclusion.

Biem (talk) 17:41, 2 May 2009 (UTC)

Biem, I don't know how many times I can say it, I am not opposed to placing a pro-hormesis reference in this article, I just want to to be one that hasn't been roundly refuted.

I am sorry I didn't explain the bias problem well enough to you, so lets try this. If there is any covariate, or transformation of a variable that is not included, or there is a measurement error in a right hand side variable, then OLS can be biased. End of story.

Lets pretend that the radon levels are higher in a very very bad part of a town and that the leading cause of death in this part of town is getting shot, so much so that the mean life span is about 40. In this case, lung cancer would be virtually unheard of in the bad part of town and a regression would find a hormetic effect regardless or the actual relationship. You can see that since houses are fixed in space and that radon levels vary largely with geography, removing geography based effects is just about impossible. In this case, bullets are protective against lung cancer, a problem with all analysis of deaths.

What's worse, a county based analysis is even more susceptible to this type of bias. Here you can not compare people who live close to each other but have different radon levels, so any bias of this type will be even worse. As an example, culture can vary by county and this can be based on agriculture. If high radon soils are associated with good livestock raising soils. Then people who eat too much meat (and therefore die younger) will have less lung cancer, radon will appear to be protective even if it increases the risk of cancer. PDBailey (talk) 19:21, 2 May 2009 (UTC)

OK, Pdbailey (I like the idea that bullets are protective against lung cancer...), but, once again, the purpose of Pr. Cohen's study was (in that case) simply to test the Linear no-threshold model - not to demonstrate a radiation hormesis effect. It is quite unfair to say it has been "refuted" because it has not proven a thesis (radiation hormesis) that it was not discussing in the first place, and on which it has not drawn any conclusion ! With respect to its official aim -test the LNT model- Pr. Cohen's paper is relevant and has not been refuted : the LNT model fails to describe what happens to low-dose exposures to radon. That's all, and that's factual.

I understand that the same paper could also be used (by others, in other contexts) as a possible proof to support the idea of a radiation hormesis effect. This was not the aim of Pr. Cohen, and this is not the reason why I added the reference to the radon article. This seems to be the basis of your objection. OK, then we agree : Pr. Cohen's article does not demonstrate a radiation hormesis effect - that was not its purpose. Good. So what?

Now that I've said that I agree with your point, can you understand that this may not be my preoccupation, and read and understand what I wrote (in this sub-section) ? "I just like the diagram, because it makes it obvious that there is more to say about radon than a simple LNT prediction" - that's all...

Thanks in advance, Biem (talk) 17:11, 3 May 2009 (UTC)

(break) Test of the LNT or of a hormesis effect?

Biem, I am not really sure what to say. There is a published work refuting Cohens work, it is well accepted. I have you several additional mechanisms by which one could get such a false result. Cohen's paper fails to test LNT, end of story. It is therefore uninteresting and not germane this article. PDBailey (talk) 23:40, 3 May 2009 (UTC)

I have no access to the work you quoted, so I can't guess what its argument has been - I can only juge by the preceding criticisms, which were about statistical bias of ecological studies : their "demonstration" was beside the point. Have you read that article? How could it justify the LNT model, has it explained the effect by a new factor, or demonstrated that it was an artefact, or argued that it might have been one? Biem (talk) 10:21, 4 May 2009 (UTC)

I think they say it pretty clearly in the abstract, "Our assessment of the study's approach, including a reanalysis of its data, also indicates that the likelihood of strong, undetected confounding effects by cigarette smoking, coupled with approximations of data values and uncertainties in accuracy of data sources regarding levels of radon exposure and intensity of smoking, compromises the study's analytic power."[22]. Your principle arguments appears to be that (1) I am damning a particular research design and you just don't accept that, and (2) That Cohen has responded. Here is the problem with these. (1) Yes, research designs that yield potentially biased results should be damned, they yield potentially biased results. There are large scale county based papers that do a good job of getting around these problems, this is not one of them. (2) Cohen's response appeared in a journal with a 90%+ acceptance rate, not as a rejoinder in the journal that published the rebuttal. This is a bad sign for the article. PDBailey (talk) 01:35, 5 May 2009 (UTC)

Well, Pdbailey, apparently you have not read that article you use as a proof, then? At least, read the abstract thoroughly.

What has been the purpose of the review, study the specific inverse relationship detected, or defend the LNT theory as such? "an inverse relationship has been suggested between residential low-dose radon levels and lung cancer mortality [...]. While this study has been used to evaluate the validity of the linear nonthreshold theory, the grouped nature of its data limits the usefulness of this application" : My reading is that the relationship itself has been studied, and the paper concludes that in this case, "the study's approach [...] compromises the study's analytic power", that is, the relationship itself cannot be used to make reliable predictions. Has the article explained the effect by a new factor ? No. Has it demonstrated that the result was an artifact ? No. It has just argued that it might have been one.

Yet another demonstration of the "ecological fallacy" argument, then? not even that, look at the conclusion : "The most clear data for estimating lung cancer risk from low levels of radon exposure continue to rest with higher-dose studies of miner populations". The specific question studied in that paper was, what is the best way to estimate cancer risks from low level radon exposures. Not to defend LNT as such, not to debate on the reality of an inverse relationship, its purpose was simply to evaluate whether the best data to estimate radon risk was Cohen's study (ecological as it may be) or the extrapolation of minors studies (extrapolation as it may be).

You seem to conclude that "Cohen's paper fails to test LNT, end of story" - well that's your own personnal conclusion, not what the paper you use as a "demonstration" says. Has Wikipedia rules changed to the point of accepting personal conclusion in the redaction of articles? Especially when your conclusion fails to be verified on the very article used as a justification?

As for your WP:REDFLAG objection : There is nothing so extraordinary with Cohen's paper finding an inverse relationship. As the French academy pointed out, "a meta-analysis of experimental animal data shows that in 40% of these studies there is a decrease in the incidence of spontaneous cancers in animals after low doses. This observation has been overlooked so far because the phenomenon was difficult to explain." ([23]). 40% cases show a reverse relationship, and 60% are unconclusive - The "extraordinary claim" would had been not to find a reverse relationship, in that case...

Biem (talk) 06:13, 5 May 2009 (UTC)

Biem, the point of the article is that Cohen's paper fails to test LNT because it does not have any power and he failed to take the low power into account. Again, just because a method is bad and you don't like that a method is bad doesn't mean that it can be used. PDBailey (talk) 12:08, 5 May 2009 (UTC)

Have you read it, yes or no? Your interpretation is not what the abstract reflects anyway. Furthermore, the point here is not to discuss hormesis effect or LNT validation (which should be done in the corresponding articles), but simply to show an graphical example of study that finds a reverse dose-effect relationship. So, please, stop waving arguments which do not correspond to the aim of the paper, nor to the reason why the graphic was added! If you have another example of reverse dose-effect graph, it will be welcome, I don't care for this particular one...

I would suggest to write a separate section on this question, so as not to be limited by the graph caption. Biem (talk) 16:00, 5 May 2009 (UTC)

Biem, neither I nor my university subscribes to HPS, so I have not read the article. However, an abstract is a summary of the article. My interpretation is this, they point out that the error terms were not well calculated by Cohen and so test was less powerful that he suspected. in the end their re-analysis with better error terms says that you can not reject the null. Here is one better than a section on this, how about an article titled Radiation hormesis. PDBailey (talk) 16:16, 5 May 2009 (UTC)

Structuration

Hello, PDBailey, I've tried to restructure the section "Health incidence of radon exposition", and I read the articles that made a case-control study on radon effects: actually, most of them seem to detect trends, but nothing much convincing as far as hard fact is concerned. I reformulated accordingly and completed the " Epidemiology studies" section. I seize the opportunity to re-read the article and tidy it a bit. Feel free to edit whatever you want to correc (with due respect to Wikipedian principles, of course). Sincerely, Biem (talk) 20:23, 5 May 2009 (UTC)

Biem, the section looks good, but I would still remove that crazy graph. Why not graph the Thompson et al. result? PDBailey (talk) 02:45, 6 May 2009 (UTC)

No graph is ready-made and available on the net :( If you have access to the article and its data, representing the corresponding graph is easy and would be fine as well. But the abstract does not give much details on the confidence intervals, and without CI, the results are quite meaningless. Biem (talk) 04:10, 6 May 2009 (UTC)

Suppressed paragraph - radon in nuclear power plants

"Radon, along with the noble gases krypton and xenon, is also produced during the operation of nuclear power plants. A small fraction of it leaks out of the fuel, through the cladding, and into the cooling water, from which it is scavenged. It is then routed to a holding tank where it remains for a large number of half-lives. It is finally purged to the open air through a tall stack, which is carefully monitored for radiation level."

No reference is given, no hit on the net, and there is no way radon can be produced in nuclear reactors in significant quantities : it is too heavy to be a significant fission product, and too heavy to be an activation product. Where does this "info" comes from? Biem (talk) 06:21, 7 May 2009 (UTC)

I think the idea might be that it is a decay product, but there are long halflived intermediates between the U and the Rn. Here is a paper [24] that says the air purification system actually reduces indoor radon below the level of other structures. I think most of the power production radon comes from mill tailing. PDBailey (talk) 15:11, 7 May 2009 (UTC)

Indeed, but in that case it has nothing specific to do with "nuclear power plants", since the same would be true for any concentration of uranium (more or less, it depends on its chemical history), and mill tailings are far more productive indeed. OK, I'll let it suppressed, then, it has no added value to the radon article. Biem (talk) 15:53, 7 May 2009 (UTC)

Not really, mill tailing easily degas while the ore (in place) the less of the gas makes it to the surface. But the claim that was put forward is very farm from this. PDBailey (talk) 19:02, 7 May 2009 (UTC)

NFPA appreciation

The "health=4" seemed incorrect : exposure to radon does not cause death as hydrogen cyanide would. I changed it to "health=0" in the article, but is there reference data for that ? Biem (talk) 06:07, 9 May 2009 (UTC)

I searched for a while and could find nothing. If we have no reference, I say it has no business on the page, I'll remove it. PDBailey (talk) 22:20, 10 May 2009 (UTC)

Mmm... I was looking for general reference, like [25], not a specific one for radon. The levels are quite straightforward, there is no need for specific reference to appreciate a level : flammability and reactivity are clearly 0, the thing is radioactive indeed, the only thing is about health effect : most of the time, a short exposition (the one considered by firemen...) "Poses no health hazard, no precautions necessary", unless the gas is highly concentrated and in huge amounts, in which case "Exposure would cause irritation with only minor residual injury" - but I can't imagine such a concentration staying anywhere for very long.

On the other hand, reference or not, the added value on the page is quite questionable. Biem (talk) 06:37, 11 May 2009 (UTC)

OK, there is a reference : [26] - apparently, any known carcinogen is considered as a health hazard and labeled as carcinogen - whatever the concentration?!?... Now, see the discussion here [27] : "Technically, if employees were in the room for one hour and the average Rn-222 concentration over that one hour was greater than 25 pCi/L, then the room must be posted." : employers should designate their offices as radioactive hazards if the radon level is above 1000 Bq/m3... This needs to be read carefully. Biem (talk) 07:25, 11 May 2009 (UTC)

Health incidence of radon exposition

This section is a bit of a beast and, to me, appears best fitted for a radiation dose response page rather than this page. PDBailey (talk) 12:54, 15 May 2009 (UTC)

I'd actually say that there is a fair amount on this page that regards epidemiology and statistics and appears to regard environmental carcinogens with special attention to radiation more than radon. PDBailey (talk) 18:28, 15 May 2009 (UTC)

I'm not sure to understand what "a bit of a beast" means, sorry... could you explain the phrase? just taking it as an opportunity to learn something, no offense meant.

I agree that the section would (also...) be OK for a dose-response page ; and if I ever translate to low level radiation the one I wrote on fr:Faibles doses d'irradiation it could take its place there, but right now both pages are empty, so the best place right now is on the radon page since I'm working on it ^_^

This may help to understand why the linear model was chosen in the 1980's (with BEIR IV), because they knew not better at that time, and maintained in the 2000's (with BEIR VI) for lack of better choice, although the only thing that has clearly been proven in the meantime is that the dose-response is certainly not linear (sounds silly ? put yourself in the general surgeon's shoes, and consider the options...). I think I may need this section as reference to clarify some technical point that may arise in this explanation, if it's in fact useless it may of course be reduced or suppressed in the final version.

The two things I would like to clarify in the article are (1) the death toll attributed to radon is really a model-dependent output, not an observed and verifiable fact ; (2) the "correct" health policy about radon strongly depends on the "real" dose-effect relationship. This should explain to the reader why studies on low level exposition to radon are so controversial. I'm writing slowly, because (besides the fact that I write just a few minutes a day...) I'm searching for references available on the net that would correctly justify these points, and since the debate is very controversial, good neutral references are the exception (and hard to find). If you find relevant references, you will be welcomed to share them.

Sincerely, Biem (talk) 18:40, 15 May 2009 (UTC)

Missappropriation of Darby

The following statement was referenced with Darby et al.

There is great uncertainty in applying risk estimates derived from studies in miners to the effects of residential radon, and direct estimates of the risks of residential radon are needed.

I think this is a fair assessment of the article's second paragraph in the Introduction. However, the paper is titled, "Radon in homes and risk of lung cancer: collaborative analysis of individual data from 13 European case-control studies." And so, before the article was written Darby, et al. argue that there needs to be more work on home radon doses. However, the conclusion does not appear so guarded. In fact, they appear to think their paper provided a reasonable answer

We have shwon that residential radon produces substantial hazards, particularly among smokers, even at concentrations below the action levels currently recommended in many countries of a few hndred Bq/m³

Because of this, I have changed the text to read,

While there are studies showing no threshold for response to radon as low as 100 Bq m^-3 (2.7 pCi/L), lower doses have not been explored.

I think this is reasonably guarded and at least agrees with the substantial gist of the article cited. PDBailey (talk) 23:40, 28 June 2009 (UTC)

You misplaced the correction : the statement was a conclusion of the "Health incidence of radon exposition" section, which discusses what is actually known : high-level exposures to radon (typically, above 20-50 WLM) increase the relative cancer risk. But, as the article says, "There is great uncertainty in applying risk estimates derived from studies in miners to the effects of residential radon, and direct estimates of the risks of residential radon are needed.", which logically introduces the next section dealing with "Studies on domestic exposures".

Your correction misses the point of making a transition ; and the discussion of this study's results should take place in the section "Epidemiology studies of domestic expositions" since that's just what it is.

As for this paper's results, they are already presented in the last sentence of the section "Epidemiology studies of domestic expositions". Is something more needed?

All in all, I find it better to switch back to the previous version, but do not hesitate to suggest improvements. Thanks for saying that it is a fair assessment of the article's second paragraph, anyway. Does that still makes it a "misappropriation", really?

Biem (talk) 06:02, 29 June 2009 (UTC)

I think I see your organizational goal now, and I find it very confusing. How about we organize it like this: (1) description of the nature of the health hazard (this is the section titled "Health risks"), (2), recommended dose models by leading bodies, (3) the science that underlies these recommendations: (3.1) miners studies, (3.2) house studies. PDBailey (talk) 14:14, 29 June 2009 (UTC)

It would actually be very confusing ^_^ ... and would be contrary to what I understand of Wikipedia's NPOV policy. The problem is that the scientific situation is very different between high exposures (miners studies) and low ones (domestic exposures).

On the one hand, the "Health incidence of radon exposition" has been studied and demonstrated through "Cancer on miners", this is why and how the "Health risks" have been studied, and that led to "Effective dose and cancer risks estimations" - all this section has nothing to do with domestic and low radon exposures. Scientifically speaking, that part is hard fact, rather consensual, and there is little debate about these models used in these high-level exposures - there is some debate, actually (the error bars of miners studies do not always overlap...), but nothing very dramatic, and everybody agrees that radon increases cancer risks in this exposure zone.

On the other hand, a lot of "Studies on domestic exposures" have been made, because it is a "Major source of natural radiation" ; but globally, "Epidemiology studies of domestic expositions" are not conclusive. This is not science, but research, and should not be presented as "scientifical knowledge" or "hard fact" - since it is not. These studies use indirect approaches, the results are contradictory, and the error bars spread widely across what the study is supposed to show.

So, on the one hand, indeed, there is indeed "science that underlies this position", but on the other hand, the hard facts gained in miners studies are used as arguments to say that the models could be extrapolated, and that there is "no reason not to extrapolate" (actually, there are very good reasons given by radiobiology not to extrapolate, but that kind of hard fact is usually not mentioned - guess why?). That's just beliefs and opinions. You can't just pretend the situation is symmetrical, because that would be making a choice in that debate, and present as "true" what is in reality polemical and (scientifically speaking) conjectural.

Regards, Biem (talk) 18:20, 29 June 2009 (UTC)

Wikipedia:No original research, remember?

Pdbailey, Wikipedia:No original research clearly forbids you to draw your own conclusions like in this modification, and especially not by misquoting references.

You pretend that "pooled epidemiologic radon studies have found trends to increased lung cancer risk from radon below the EPA's action level of 4 pCi/L. At this level, some studies have found that there is an effect significantly different from no effect" when the cited article [28] says nothing like that, simply states that "Radon [is] A likely carcinogen at all exposures" (remember: "likely" does not mean "proven"). Actually, a quick look at the "material and method" of that article should convince you that this is a review article, not a pooled study - have you noticed the difference? BTW, you erred in your conversion, 200Bq/m3 is more like 5 pCi/l, not 4...
You pretend that "Notably, the latter deviance from zero at low level convinced the World Health Organization a dose response that has no threshold below which radon is safe" when the cited article [29] has not a word about any deviance from zero (?). Just the usual stuff that nothing contrary has been found - remember the scientific saying, never to conclude on a negative result?

Actually, if you look seriously at the results of this pooled study, given here [30], you will see (figure 1, p. 141) that no effect is observed at 20 Bq/m3, and that the error bars all cross the "no-effect" axis until the very last (at 350 Bq/m3). Is that the proof you are speaking of? Furthermore, these are but case-control studies, and everybody knows how error-prone these are...

Please stop this POV-pushing about would-be "conclusive" radon effects at low exposures, this is tiresome. Thanks in advance. Biem (talk) 20:21, 29 June 2009 (UTC)

Beim, you write, "You pretend that "pooled epidemiologic radon studies have found trends to increased lung cancer risk from radon below the EPA's action level of 4 pCi/L. At this level, some studies have found that there is an effect significantly different from no effect" when the cited article says nothing like that." on the contrary, the article reads (in the lead material), "The dose-response relation seemed to be linear with no threshold and remained significant (p=0.04) in analyses limited to individuals from homes with measured radon [less than] 200 Bq/m³." And then in the body, "We have shown that residential radon produces substantial hazards, particularly among smokers, even at concentrations below the action levels currently recommended in many countries of a few hundred Bq/m³." it is on this basis that I attribute to them the claim that radon below a few hundred Bq/m has been associated with increases in lung cancer, a finding of the paper. I agree this result can not be taken to the bank as it is, and that other studies using similar methodology would help to corroborate these results, but it is the result of the paper and NPOV requires that this not be suppressed. In deed, this result has been agreed to by a well established medical body (WHO). Also, look at figure 1.1 (the same figure you cite, the line at 136 (top panel) and 119 (bottom panel) does not cross the horizontal line at unit relative risk, also see the error bars in Table 2 where the confidence interval does not include one.

Finally, there is no assumption that the dose response is linear, the paper actually tests that hypothesis. They write, "Models with no effect up to a 'treshold' dose and then a linear effect did not fit significantly better than a linear effect with no threshold; in such models the upper 95% confidence limit for a possible threshold was 150 Bq/m³ measured radon." This suggests that this is not just a tacet acceptance of the LNT model, but they actually tested a more complex model, rejected it based on its increased complexity and inability to provide substantially more explanatory power, but noted that even if one did not want to apply this heavily used and well regarded statistial criterion, the upper bound on a threshold that the data supports would be as low as 150 Bq/m³.

I hope we can now agree, (1) this paper has strong conclusions and disagrees with the current article's text. (2) this article is not regarded as a quack article, but its use has been endorsed by at least one review body. As such, it belongs on this Wikipedia page. PDBailey (talk) 03:24, 30 June 2009 (UTC)

The Darby article is given here. Read it seriously, with a critical eye. Look at table 3 : nearly all studies are compatible with "no effect" in the 95%CI, and the pooled results barely make a 1.01 above the 1.00 "no effect". Have a look at figure 4 : all the data shown are inconclusive...

The other Darby article collaborative analysis of individual data from 13 European case-control studies pretends that the data is compatible with a linear relationship? sure enough, but it would be compatible with any other kind of relationship, it hasn't proven anything. Have a close look at figure 1, you will see that the data actually falls into three groups : in the 0-100 Bq/m3 no effect is detected ; in the 100-400 Bq/m3 the relative risk is around 0.5 ; and at 700 Bq/m3 it climbs at 2. Doesn't that suggest a threshold to you, especially when radiobiological studies have concluded that the effect cannot be linear? The linear model does not fit very properly in the first place, then "Models with no effect up to a “threshold” dose and then a linear effect did not fit significantly better", sure enough, but both the data and the radiobiology suggest a threshold and a plateau effect, which was not tested - quacks, really, that ignore facts and relevant studies from other fields.

And remember, these are case-control studies, where the real effect can be widely outside the error bars. How conclusive does that seem? Your user page states you are a mathematician and a statistician, you should know better than that.

The papers may have been published in a review, but is still very polemical and disputable. Actually, the French Academy of Sciences 2005 report was (explicitly) written in response to another article by the same author (Berrington dG, Darby S. Risk of cancer from diagnostic X-rays: estimates for the UK and 14 other countries. Lancet 2004;363:345-51.), precisely to denounce it as a quack, because enough is enough (this LNT lobbying has been denounced as the biggest fraud in modern science, in other publications)... A national academy of sciences, against a polemical searcher? Open your eyes, now, its's the same author and the same method - an activist with unreliable results twisted to gain some fuzz around his name. Twisted by knaves to make a trap for fools...

If your only aim is to quote that article because "NPOV requires that this not be suppressed", then be happy, it was already quoted. But with such an argument, why do you insist on suppressing the Thomson article, which "showed substantial cancer rate reduction between 50 and 123 Bq per cubic meter relative to a group at zero to 25 Bq per cubic meter" - just because it does not fit your views ?

Be honest and stop that now. Biem (talk) 07:00, 30 June 2009 (UTC)

First, I was including a reference to the wrong 2005 Darby article, thanks for pointing that out. You are right that I wanted to reference the latter 13 countries one. However, having fixed that, I will point out that you did not respond to my above quotes at all. Instead you attacked the paper and the authors of the paper, this is a problem, especially because a leading health body embraces them showing that it is in the mainstream of medical wisdom. Please do not undo or otherwise remove this article again. Thompson is in the article and this should be in the article as well. If you still insist, lets ask for a third party to comment. PDBailey (talk) 13:34, 30 June 2009 (UTC)

The debate about the effect of low level exposures to radiation goes right back to 1900. Pierre Curie's father was a homeopathic doctor and the theoretical model for the original use of radiation from radon and radium in curietherapie was that a small dose of something that is fatal in large doses might be therapeutic. (Pierre experimented on small rodents). Still in the 1980s there were physicists with radiodermatitis on their hands who thought that their low exposure to radiation might have had a therapeutic effect.

I wanted to post a warning that I fear there is confusion underlying the paragraph on Radon in Radiography. That paragraph has no reference given, when I reseached my PhD on the history of the radiotherapy of cancer I came across no reference to it.

It is undoubtedly the case that in many countries radon gas was generated from radium salts in solution, stored in glass or gold 'beads' and used in the treatment of cancer, both surgically implated and placed in a mould on the skin in a way intended to focus radiation on the lesion. The sourcing for that is there in the article and could be massively extended. There is however no reference for radon in radiography in the modern meaning of generating images using (non-light) radiation. Before the first World War when anti-German feeling meant that Roentgenology changed its name to radiology curiethapie was used to describe the use of radon and radium therapy of cancer, lupus, TB of the skin etc.

Of course, people also tried inhalation therapies as well and the drinking of radon solution for the treatment of arthritis. All of the first 4 technicians at the London Radium CLinic where such treatments were given died as a result of changes to their blood cells. In Manchester, Rutherford (before he moved to Cambridge), had to clean up the spilt radium solution that was being used for the generation of radon beads. Soddy, before he worked with Rutherford was also involved in the production of Radon beads.

It is worrying to read on this site that radon solution therapies are being offered again. Polonium killed Litvinenko and is a breakdown product of radon. The history of spillages , explosions and losses in these therapies is quite worrying, in Britain legislation exists to control who can offer radioactive tretments, are patients in the USA not offered similar protections?. Carolinerutter (talk) 13:13, 17 September 2009 (UTC)

Time to go the extra step?

I belive that we are getting closer to making this article FA material. If you find things that need to be done, please create a list that details what you think should be done. Thanks! Wii Wiki (talk) 21:00, 6 September 2008 (UTC)

Expand the lead to 3-4 paragraphs per WP:LEAD
Why is there one ref all by itself under References? --Cryptic C62 · Talk
Generally speaking the article is too long. I have created an article at Health effects of radon for the huge amount of health information.
The writing could be more cohesive. I see lots of great facts that need to be strung together with prose. :)
Images need to have alt text added. ManfromButtonwillow (talk) 10:46, 23 December 2009 (UTC)

Article length

This article is quite long, and several sections seem to be candidates for a new article (or new articles). In particular, the sections entitled "Health incidence of radon exposition", "Studies on domestic exposures", and "Health policy on radon public exposure" seem too in-depth for a general coverage of radon; they should be summarized, and the details moved to another article (or other articles) specifically addressing these issues.—Tetracube (talk) 18:54, 9 October 2009 (UTC)

I think this is one article, but I agree that it does not belong in this article at the length currently used. I think one to three paragraphs would be nice for this article and another article on the health effects of radon in another article. PDBailey (talk) 15:14, 12 October 2009 (UTC)

Would it be Health effects of radon ? Why not... Biem (talk) 21:16, 15 October 2009 (UTC)

Sounds like a good idea.—Tetracube (talk) 21:18, 15 October 2009 (UTC)

Sounds good to me too. PDBailey (talk) 00:09, 16 October 2009 (UTC)

Okay, I did it. I just copied and pasted those sections, stole this article's lead, and pasted it under Health effects of radon. Is this okay? ManfromButtonwillow (talk) 08:39, 23 December 2009 (UTC)

Now the section in this article needs to be summarized. --mav (please help review urgent FAC and FARs) 18:15, 26 December 2009 (UTC)

Been working on it in a text editor. I'm planning on finishing it today. ManfromButtonwillow (talk) 22:27, 27 December 2009 (UTC)

An important zero

If someone knows about measurement, and is logged in... please you should change the melting point to: Melting point 202.0 K

Done. Materialscientist (talk) 22:15, 6 May 2010 (UTC)

"Radon water"

Why isn't there an article discussing the use of "radon water", a form of quack medicine from the early 20th century? Beyond this use, radon was also used to "heal" wounds in hospitals, long before anyone knew of radiation poisoning or cancer. It was applied to bandages to "speed the healing process" ... this had great short term results (faster tissue healing), but it caused cancer pretty soon after. In fact, doctors initially considered radon to be somewhat of a panacea due to its "healing" effects. It was around forty years later that the dangers of ionizing radiation were finally appreciated. And yet none of this is discussed anywhere! Fuzzform (talk) 08:41, 12 July 2010 (UTC)

Is it really odorless?

The lead states that radon is odorless. This may be a picky point, but I very much doubt anyone has ever taken a breath of pure radon to find what it smells like. (And if they have, they probably didn't live long enough to describe their experience.) So it doesn't seem to me that the article should say anything about the odor. Of course, what it probably means is that radon is odorless at any concentration you are likely to encounter; maybe the wording could be changed to reflect that.Kevin Nelson (talk) 15:13, 6 June 2010 (UTC)

All of the noble gasses are odorless. This property is due to the simple fact that they're inert (i.e. low to no reactivity). These elements can't react/bind with the olfactory receptors in our noses. Trying to smell one of the noble gases would be like trying to smell diamond... maybe there are other odorous contaminants in a mixture of (for example) xenon and other gases, but the pure element itself odorless. Biologically it makes no sense that anything nonreactive would have any sort of scent whatsoever. Fuzzform (talk) 08:53, 12 July 2010 (UTC)

Radon in imaging

As the author of a PhD thesis on the history of the Radiotherapy of Cancer (University of Manchester Institute of Science and Technolgy 1985? it was a lon time ago). I am concerned about the un-referenced paragraph on the use of Radon in radiography. In the early years of the twentieth century the word radiography did not really exist. In the years before the anti german feeling generated by the first world war Roentgenography was commonly used. Radiotherapy was at that time called curietherapie in an analogous manner.

I never came across any reference to the use of radon in the production of medical images: it was undoubtedly used in the glass and gold seeds reffered to in the paragraph headed radiotherapy. Since there is no reference to any source given in the paragraph headed 'radiography' I suggest that the paragraph be deleted until some reliable source is found. It is likely that there may have been an error at some point in the reading/writing/translation/interpretation of the the term 'radiography' which now means exclusively the generation of images using radiation.

If I am wrong and there is a reference - let's include it. Thanks Caroline Rutter

My guess is that radon was used in a sketchy manner, prior to the development of what we know as "modern medicine". Unfortunately, references are far and few between these days, particularly in regards to the history of science/medicine. In any case, Wikipedia policy says that any unreferenced material can be deleted at any time. Fuzzform (talk) 08:59, 12 July 2010 (UTC)

"The actual number of how high these radon levels were measured at is not known."

An IP user has attempted to add a sentence like "The actual number of how high these radon levels were measured at is not known." several times. This still seems like a contentious claim. Somebody did measure how high the radon levels were, how can it not be known? Is there a reliable source that says these levels are definitely not known? Please help me understand what the intent is here. Thanks. Zad68 (talk) 20:03, 3 May 2012 (UTC)

Physical properties

68.188.203.251 (talk) 02:40, 5 September 2012 (UTC)

Please explain how this radon glow from condensation would present itself. Example: would a p trap in a shower drain with only a strainer cover in a small apartment in a high rise senior subsidized tower ever glow blue due to condensed daughter particles from radon gas? Would this glow be the emission of alpha particles? Would a glow sufficient to be seen at night without light be significant? If this glow is seen 4 nights out of 7 for hours at a time be of concern? — Preceding unsigned comment added by 68.188.203.251 (talk) 02:07, 5 September 2012 (UTC)

natural sources of radon

207.75.81.12 (talk) 17:14, 19 October 2012 (UTC) Underestimated amounts of radon off gasses from tree transpiration. Article:http://www.radonleaders.org/sites/default/files/Role%20of%20Vegetation%20in%20Enhancing%20Radon%20Concentration%20and%20Ion%20Production%20in%20the%20Atmosphere.pdf Was not able to find original research on wether or not our human history is an adaptation to significant radon exposure.

Tasting radon

I don't know whether it's been confirmed that radon is tasteless. Anyone who inhaled it either would not be able to discern it at all if the quantity is too small or be killed from the alpha radiation.Jasper Deng (talk) 05:56, 9 February 2012 (UTC)

Now it's been cited. Double sharp (talk) 03:54, 23 November 2012 (UTC)

Conflicting information

In the concentration scale section, the third section of the table says:

"If testing shows levels less than 4 picocuries radon per liter of air (150 Bq/m3), then no action is necessary."

In the next section of the table it says:

"If levels are 20 picocuries radon per liter of air (800 Bq/m3) or higher, the home owner should consider some type of procedure to decrease indoor radon levels."

The first suggests that above 4 pCi/L there is a potential problem, while the second says that the home owner "should consider" remediation above 20 pCi/L. It's a long way from 4 to 20 -- where should the line actually be drawn? . . Jim - Jameslwoodward (talk to me • contribs) 14:27, 6 March 2013 (UTC)

Radon water picture

This picture is odd enough that this may be WP:OR, or at least needs a citation. It is described on Wikimedia as "a system for (supposedly) diluting Radon into drinking water," but I'm not convinced that's even right. The French translation matches; I can't confirm the Japanese, but I have a suspicion that the intent might be to reduce radon concentration. Could "dilution" could have been misunderstood in translation? Surely it would not be legal to add radon to water in Japan? From examination, it's conceivable that the stainless vessel in the corner could contain some radium-bearing gravel, and the need for radiation shielding might explain why it looks heftier than your typical drinking water component. The other two containers could be filters to prevent pure radium from getting through. But this could also just be an ordinary home-made 3-stage filtration system that would remove radon's parent and daughter elements naturally found in groundwater. There is no bubbler that could really remove radon, but letting the water rest in that glass jar at the end would help evaporate it out.--Yannick (talk) 18:53, 1 December 2012 (UTC)

You raise some intriguing questions. A full translation of the Japanese might be helpful, perhaps you could ask for assistance at the Help Desk (http://wiki.riteme.site/wiki/Wikipedia:Help_desk)? Reify-tech (talk) 14:40, 6 March 2013 (UTC)

Photograph of actual radon

My opinion is that this greenish photograph should be removed. It is not a photo of radon, but a photo of some kind of needle presumably filled with radon which induces radioluminescence of the phosphor layer on which the needle is resting. Radon is a colourless gas, and if no one manages to find a photograph of actual radon in liquid and/or solid state which glows on its own, it's better not to have any photo at all to avoid confusion. Endimion17 (talk) 14:04, 27 March 2013 (UTC)

You make some good points, but I think that adding an explanatory caption would prevent misleading readers in this regard. A photo does help the reader to remember information, but should be explained carefully to prevent misconceptions. It certainly is difficult to illustrate a colorless gas, but I think it has been possible to refine enough of the element to allow its visualization in some form. It would be even better to find a picture of the concentrated (liquefied) element (as in Oxygen), or perhaps a gas discharge tube (as in Xenon). Radon is alleged to glow red in an gas discharge tube, but I don't have a verified source handy at this moment. A picture of the spectral signature would also be helpful. Reify-tech (talk) 14:51, 27 March 2013 (UTC)

I added a spectrum image. I know it's not in colour, but this one has historical significance (Rutherford 1908). Double sharp (talk) 16:06, 27 March 2013 (UTC)

But I would recommend keeping the greenish picture in the infobox for now: it at least has some radon in it (it's just not visible), while the spectrum picture doesn't (although it describes a property of radon). I do not think a liquid/solid photo of radon has been made yet, but I will check. Double sharp (talk) 16:09, 27 March 2013 (UTC)

I found a picture that claims to be of liquid radon at [31]. Liquid Rn is transparent; the glow is probably from ~~Čerenkov radiation~~ Cherenkov radiation. However this pic just raises more questions:

How on earth did they make this sample?
Why is there no radiation shielding?
Why does the label not say anything related to radon?
Radon boils at −61.85 °C. How is this sample being kept liquid? I don't see anything present that would allow that.
How did this company get the Rn anyway? I don't think they have the facilities for it (all they do is test for and mitigate Rn gas in Virginia.)

Overall, I am suspicious of this picture. It is probably just a generic photo of ~~Čerenkov~~ Cherenkov radiation, and not liquid Rn. (It's not like we have anything better, but I would rather not risk putting such an uncertain image into the infobox.) Double sharp (talk) 12:38, 28 March 2013 (UTC)

BTW, this picture is an admitted photomontage, so should not be used. Double sharp (talk) 12:40, 28 March 2013 (UTC)

You raise some of the same questions that occurred to me immediately. An attention-getting picture, but not necessarily what it is claimed to be. Hopefully something better will turn up. Also, I agree that the Rutherford spectrum image is of historical interest, and is well-placed in the article. Reify-tech (talk) 14:34, 28 March 2013 (UTC)

Also, R8R Gtrs has gently admonished me to not use the diacritics. Remedied! Double sharp (talk) 02:37, 31 March 2013 (UTC)

Conflicting discovery dates

The history and etymology section of this article says that radon was discovered in 1900. But the box at the beginning says 1898. Is it just rounded, or altogether incorrect? -- ^(T)Numbermaniac_(C) 08:50, 7 June 2013 (UTC)

GA Reassessment

This discussion is transcluded from Talk:Radon/GA3. The edit link for this section can be used to add comments to the reassessment.

This article contains a lot of unaddressed citation needed tags (most of them years old), thus failing criterion 1b, which requires citations for statistics and challenged material. I will wait a week before closing this reassessment so editors can have the opportunity to fix these issues.--FutureTrillionaire (talk) 01:05, 17 July 2013 (UTC)

I've handled all but two of them. DMacks (talk) 05:23, 18 July 2013 (UTC)

...which User:King jakob c 2 and I cleared. DMacks (talk) 08:39, 24 July 2013 (UTC)

@DMacks: Hold on, the article contains at least 5 one-sentence paragraphs (mostly in the Application and Health risks sections). MOS:PARAGRAPHS (which is part of MOS:LAYOUT, whose guidelines need to be met to satisfy criterion 1b) says: "The number of single-sentence paragraphs should be minimized." --FutureTrillionaire (talk) 13:55, 24 July 2013 (UTC)

All done (I think?) except for the "industrial radiography" in Radon#Scientific. DMacks (talk) 15:37, 24 July 2013 (UTC)

Done that one now also. DMacks (talk) 21:55, 24 July 2013 (UTC)

Nice job. All the issues I've found have been fixed.--FutureTrillionaire (talk) 22:27, 24 July 2013 (UTC)

Result: Kept.--FutureTrillionaire (talk) 22:27, 24 July 2013 (UTC)

If this article mentions a study that found only an increased risk when exposed to passive smoking, should that not be mentioned in the domestic-level exposure section? Sounds important enough, it means that most people don't have to worry about radon! Ssscienccce (talk) 08:40, 7 October 2013 (UTC)

Bq/m3 or kBq/m3 ?

"The World Health Organization issued as guidelines (1988) that remedial action should be considered when the radon activity exceeded 100 kBq/m³ in a building, and remedial action should be considered without long delay if exceeding 400 kBq/m³."

This figure is taken from reference 1 (Toxological profile for radon), but is probably erroneous : living at 100 kBq/m3 would lead to 8 Sv/year, and no WHO official in its right mind would ever recommend that level! I suppose the "kBq" should be "Bq", more in line with the 10 mSv/year limit. Can somebody check that figure? Thanks in advance. Biem (talk) 07:19, 22 June 2009 (UTC)

We have indeed : "Concerning drinking water, the 2004 WHO Guidelines for Drinking Water Quality and the European Commission recommend that controls - for example repeat measurements - should be implemented if radon in public drinking-water supplies exceeds 100 Bq/l. The United States has proposed a Maximum Contaminant Level for radon of 150 Bq/l for private water supplies. For public or commercial water supplies, the European Commission recommends that remedial action be taken if the radon level exceeds 1000 Bq/l. A tap water radon concentration of 1000 Bq/l contributes 100 to 200 Bq/m3 to indoor air and thus corresponds to the indoor air radon Action Levels discussed above." .[32]

...and 100 Bq/l=100 kBq/m³ of course ; but that's for drinking water, not breathing air. Biem (talk) 18:46, 25 June 2009 (UTC)

Looking back at the linked to article, you are absolutely right. However, they have an interesting contribution to LNT debate. Guessing that if I added you (or another) would just RV me, lets try to figure out what the text might say here. I propose,

The World Health Organization concludes based on a meta analysis of home studies that exposure is linear with no apparent threshold and finds a non-linear but monotonic increase from 0 to 100 Bq/cubic meter (2.7 pCi/L).[33]

Oops forgot to sign PDBailey (talk) 16:14, 26 June 2009 (UTC)

I'd say, no. The problem with these analysis is that which is described in the section radon#Epidemiology studies of domestic expositions : First of all, these are but case-control studies (or ecological studies), which are a priori prone to numerous bias - so they shouldn't be taken too literally (just indications that there might perhaps be something like that...). Secondly, all these studies suffer the same problem at low doses: in these areas, the effect is vanishing (predicted and observed), and the data becomes inconclusive. The error bars are compatible with a linear effect, or with a threshold effect, or with any kind of bizarre dose-effect law, simply because the error bars are much too large for anything to be said conclusively. In this context of epidemiological approaches, to say that "The XYZ study has obtained results compatible with a linear law, and no threshold has been observed" is a truism - it would be true of any study, whatever the real dose-effect law is. You may add any number of studies that say so, and add any number of people that believe that the LNT holds, this will not amount to a scientific proof.

On the other hand, see the section radon#Dose-effect model retained : "In the radiobiology and carcinogenesis studies, progress has been made in understanding the first steps of cancer development, but not to the point of validating a reference dose-effect model. The only certainty gained is that the process is very complex, the resulting dose-effect response being complex, and most probably not a linear one." That is hard fact, it is scientifically known that the LNT cannot be correct - but nobody knows what the correct model is.

But given that, saying that so-and-so believes that the LNT may be true is just that - a belief. You may say that a lot of people think that way, it is still a belief. Add a thousand references, it won't turn it into a factual knowledge about reality, just knowledge about what people think? so what?... An encyclopedia deals with knowledge. The knowledge that can be stated has been stated above : "the process is very complex, the resulting dose-effect response being complex, and most probably not a linear one" - and that's that...

Regards, Biem (talk) 17:08, 27 June 2009 (UTC)

Biem, my essential question is this: how should we incorporate this article. Your answer appears to be, the study is valueless because you have an alternative theory that is also consistent with the data, and you reject statistical tests designed to differentiate LNT from other models out of hand arguing there can be no evidence provided that will falsify your alternative model. is that right? I have two problems with this, but lets start on if I understand the thrust of what you are saying. PDBailey (talk) 23:40, 27 June 2009 (UTC)

OK, to be precise :

(1) The article has no strong interest, because in the first place, it is not the result of the WHO cross-study, but a comment on this result ; the paper presenting the study itself would be better ; but still it would just be another case of "the data shows no evidence against LNT", which is a trivial conclusion - so what?

(2) The "alternative theory" is not mine, it is the theory presented by the French Academy of Sciences, for instance, and many other sources ; actually there is no known dose-response law (so, no "alternate theory"), but there is evidence enough that it cannot be linear.

(3) There can be no evidence from epidemiological studies that will falsify anything, be it LNT or an alternative model, this is essentially correct (and any statistician would confirm that) ; this is why it is rather pointless to add articles on that subject.

Anyway, this article deals with Radon, not LNT. If you feel this reference has to do with LNT, you should discuss it there. Sincerely, Biem (talk) 16:04, 28 June 2009 (UTC)

Apologies if I'm posting in the wrong pace here but I've spotted a really major issue out there on the web- there seems to be some confusion between Bequerels per metre cubed (Bq m3), which is claimed by the main article to be the standard measure or radon activity by volume of air, and Bequerels per metre TO THE POWER OF MINUS 3 (Bq m–3), or per Litre, which makes a difference of a thousand- fold! The document below uses the latter units: http://www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1243838496865 . — Preceding unsigned comment added by Elementperson (talk • contribs) 18:31, 15 September 2013 (UTC)

Radioactivity and smoking

Lung cancer from smoking tobacco products is higher from US tobacco products that from investigations of lung cancer vs smoking in other countries with higher per capita cigarette consumption e.g. mainland China. (This has been attributed to fertilization of US Tobacco crops from phosphate mines that once were mined for Thorium. Also note: "An additive rather than a multiplicative model has been gaining support to illustrate the connection between smoking and radon daughter induced lung cancer" [Harely N et al; Environmental Health Perspectives]. Shjacks45 (talk) 08:56, 9 January 2014 (UTC)

Testing

(2011) Journal of Environmental Radioactivity, 102 (10), pp. 901-905 Shjacks45 (talk) 09:22, 9 January 2014 (UTC)

(lighter, heavyer, lighter, heavyer)? than air

Radon is the heaviest known gas, nine times heavier than air.

  -radonseal.com/radon-indoor.htm

Lighter than air, it rises through cracks and fissures in the ground and can enter a home through cracks, joints and openings in a concrete slab, or move easily through floor, wall and ceiling framing assemblies.

  -ezriderhomeinspections.blogspot.com/2008/07/little-information-about-radon.html

Radon is the heaviest of all gases.

  -free-radon-test-kits.com/radon-gas.htm
   (guess these guys know for a fact that its the heavyest gass since chuck norris and any other gass we might discover in the future)

RADON GAS IS PRODUCED FROM THE NATURAL BREAKDOWN OF URANIUM IN SOIL , ROCK AND WATER, IT IS LIGHTER THAN AIR AND MOVES UP INTO THE HOME THROUGH CRACKS AND HOLES IN THE FOUNDATION

   -thishomeinspector.com/Radon

I could go on, if you do a search trough google and read the different articles on radon, including the wiki one, one gets realy confused over if its heavyer or lighter than air?(hot cold indoor outdoor or in open space, below ground and so on).

It get sucked in from vacum then supposedly it floats upwards because its lighter and thus travels into ventilation in roof?... Yet its heavyer than air in some articles likes to say it fills the basement pref trough cracks. then some articles says cold basements force the radon out, yet warm basements whit some fire based heaters sucks it inn, yet electric heaters just pushes it down (so the radon is realy close to the floor so getting that into your lungs i suppose would be hard unless you crawl on the floor i suppose?.

Confusion mess§ —Preceding unsigned comment added by 217.8.130.17 (talk) 07:22, 11 October 2010 (UTC)

I know this is over three years since this was asked, but radon is most certainly heavier than air by virtue of its density. That does not mean, however, that it won't diffuse to mix with normal air - remember that the gases are close to being ideal gases and that the identity of the molecule or particle has limited influence.--Jasper Deng (talk) 10:06, 7 March 2014 (UTC)

Is radon really the heaviest gase at the room temperature? Some people say that the heaviest gase at the temperature of room is not radon, but uranium hexafluoride. Radon has molar mass of 222 g/mol and UF6 has 352.02 g/mol. — Preceding unsigned comment added by 89.149.96.128 (talk) 20:34, 7 March 2014 (UTC)

Our uranium hexafluoride artucle says this compound has:

Melting point  64.052 °C (triple point at 151 kPa[1])
Boiling point  56.5 °C (sublimes)

If we're talking about chemicals that are solids at standard conditions but happen to be volatile enough to get the gas, plutonium hexafluoride has a higher molecular weight than the uranium analog. DMacks (talk) 22:12, 7 March 2014 (UTC)

Thank you, D'Macks! Yes, I've read that the compound UF6 has melting point at 64 and it boils at 56 degrees. But can it be a gaseous substance at 18° if we reduce the pressure?.. About PuF6 – it is completely new for me. Thanks for info. — Preceding unsigned comment added by 89.149.96.128 (talk) 14:38, 22 March 2014 (UTC)

Even if we're staying with chemicals that are indisputably gaseous at standard conditions, radon is not the heaviest gas. That honour goes to tungsten hexafluoride (WF₆) with a molar mass of 297.830 g⋅mol⁻¹. Double sharp (talk) 10:28, 23 March 2014 (UTC)

Also, standard conditions require a pressure of one atmosphere (about), so you can't cheat by reducing the pressure (as far as I know, zero pressure means anything becomes a gas).--Jasper Deng (talk) 09:11, 4 April 2014 (UTC)

Second most frequent cause of lung cancer

Wouldn't it be more accurate to say "second greatest contributing factor to..." or similar, given that cancer doesn't have a "cause" per se, but rather a chance of happening that's increased by exposure to risk factors (radiation, carcinogenic chemicals etc.). A bit anal, yes, but it makes the article less misleading in my opinion. 78.151.181.86 (talk) 20:57, 7 September 2008 (UTC)

I agree. This should still be fixed. Dsethlewis (talk) 19:27, 30 June 2014 (UTC)