Talk:Carbon dioxide

Conversion of v/v to m/m
I have corrected the conversion of ppm by volume to ppm by mass. The original note claims that this conversion could be performed by multiplying by the ratio of the molecular masses of CO2 and Air. The correct equation multiplies by the ratio of the densities of CO2 and Air. The difference between the density of moist air and the density of dry air is a non-trivial factor, and so volume can not be disregarded. A quick dimensional analysis will confirm that this is the correct method:

(m/m)=(v/v)(m/v)(v/m)

Or to be more explicit: mCO2/mAir = (vCO2/vAir) (vAir/mAir) (mCO2/vCO2)

Taking this approach usually gets you a ppm-m that is about 1.9 times greater than the ppm-v.

https://www.lenntech.com/calculators/ppm/converter-parts-per-million.htm — Preceding unsigned comment added by 172.97.206.190 (talk • contribs) 00:12, 8 November 2020 (UTC)

general concentration table
I came to this page trying to figure out an answer to the question "hey, my sensor is saying i have 1500ppm in the office, is that good or bad? what's the impact?" I eventually found the "below 1%" section buried in the article, and even there it's one long paragraph with lots of data.

I figured I would build a shorter summary of the data in a table. I picked some new sources for the data which might not be the best, but it's all sourced. One source might be a little dubious because it's from a sensor manufacturer which may have incentives to describe co2 levels are more alarming than the research actually says they are, but I figured this was still worthwhile, especially considering Canada (and other countries!) restrictions above 1000 ppm.

HTH! TheAnarcat (talk) 15:45, 10 August 2023 (UTC)


 * The table makes sense to me but at the same time I think you should not put any data into it that’s not well sourced. The sensor manufacturer’s website is not a primary source. Qflib, aka KeeYou Flib (talk) 23:42, 10 August 2023 (UTC)

unclear properties values in brackets
Some values have (15) or (30) added - that needs explaining or correction eg. Vapor pressure 5.7292(30) MPa, 56.54(30) or Critical point (T, P) 304.128(15) K (30.978(15) °C), 7.3773(30) MPa (72.808(30) atm) 2A01:C22:CD7C:E00:7983:CA1C:9736:D1BC (talk) 08:44, 24 August 2023 (UTC)


 * It’s not unclear. This is a widely used notation to indicate how much uncertainty is expected in a measured quantity. See the Wikipedia article on uncertainty for more information. Qflib, aka KeeYou Flib (talk) 14:28, 24 August 2023 (UTC)
 * Hm, I guess the repeating numbers 15 and 30 does bear closer examination. Maybe they are old citations? Qflib, aka KeeYou Flib (talk) 15:37, 24 August 2023 (UTC)
 * First it would be easier to understand if ± was used however if these were uncertainties then
 * 5.7292(30) MPa, 56.54(30) atm would translate to 5.7292 ± 0.0030 for MPa and 56.54 ± 0.30 atm but those are the same measurement just with different units. So the uncertainty can't be the same as 5.7262 MPa (-0.003) are 56.5132 atm and not 56.24 - so i conclude these are not uncertainties. (other 7.3743MPa is 72.77868 atm would work (72.778atm) as here the atm value is given with 3 decimals but even if we use 56.54(3)atm it seem to work but 56.542(30) would be 56.512 not 56.5132 as the certainty wouldn't have ⅒ but ¹/₉.₈₆₉₂₃₃ as a factor - So it is very unlikely that the MPa and atm values were from two different measurements with different uncertainties that accidentally have the same numerical value - while just a typo moved a decimal place. 2A01:C22:CD04:2B00:98A2:90A1:EB26:C385 (talk) 09:04, 25 August 2023 (UTC)
 * I completely agree. I think that we should therefore remove the numbers within the parentheses, and then try to find better sources. Qflib, aka KeeYou Flib (talk) 22:01, 25 August 2023 (UTC)

Ambiguous units of measurement like "ppm" and "%" across this article
There are many data with ambiguous units of measurement like "ppm" and "%" across this article (and many other articles across Wikipedia), without a clear explanation what those units stand for. Without a clear explanation, those units can stand for mass per volume, volume per volume, mole per mole or who knows what else. Can someone clarify what those units stand for, despite that is not clarified in the sources? The data about the concentrations of carbon dioxide (and other suffocating and toxic gases and substances) in the air, water, food, drinks, products, etcetera, is a very important information for readers, especially non-expert ones, so, editors should be notified about the very existence of the ambiguous "ppm", "%" and similar ambiguous units across Wikipedia. Let's discuss. I am opening a debate. What do you think? Do you agree or disagree with me, and explain why. Thanks in advance for your opinion. Bernardirfan (talk) 18:08, 30 August 2023 (UTC)


 * WP:JUSTFIXIT with a WP:SCIRS source. Zefr (talk) 19:06, 30 August 2023 (UTC)
 * I think another editor has now fixed the problem. Thanks for pointing it out. Not everything needs a debate, as Zefr rightly points out. Qflib, aka KeeYou Flib (talk) 14:09, 6 September 2023 (UTC)


 * Thank you Qlib and Zefr for resolving my clarify tags. Bernardirfan (talk) 09:41, 16 October 2023 (UTC)

Semi-protected edit request on 31 August 2023
2.49.118.238 (talk) 14:49, 31 August 2023 (UTC) But if he das he Eed yt account then I don’t see why not just follow the link to the tweet he is posting and
 * Red question icon with gradient background.svg Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate.  — Paper9oll  (🔔 • 📝)  14:55, 31 August 2023 (UTC)