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(0) In this line of messages re carbon <<monoxide>>, PLEASE note: CO2 = carbon <<di>>oxide, CO = carbon <<mon>>oxide. As with the line of messages that kept on being headed "Restrictions on scuba diving" some time after the topic had drifted away from that, haven't emailers nowadays got a facility for people replying to messages to alter the Subject: line of the message from a carbon copy of the Subject: line of the message being replied to????? This not updating the Subject: lines is likely to be a nuisance for people going through Techdiver's archive some time later trying to sort out all the messages on topic X by looking thru the Subject: lines in the Techdiver index. John Rooney <jrooney@in*.so*.ha*.ed*> wrote on Fri 22 Jul 1994 11:53:45 -1000 (Subject: intro/CO2):- (1) Herewith reformatted his self-introduction, as it had many lines well over 78 chars long and so liable to be displayed truncated by emailers: > Aloha, I've been reading the techdiver mail for a month now, but haven't gottenaround to introducing myself, so here goes...My name is John Rooney. I'm fortunate enough to live in Hawaii, on Oahu, where I've done the majority of my about 1250 dives. I'm a PADI Master Scuba Diver Trainer, but quit instructing full time to go to the U. of Hawaii, where I'm working on an MS in Oceanography. I've always wanted to get into the tech diving scene & was frustrated by PADI's reluctance to support these types of diving, and the general lack of information available. So I'm pretty stoked to have taken a Nitrox course & be taking Advanced Deep Air from Epic Dives, as well as to be learning from techdiver. Am looking forward to mixed gas & rebreathers, which I'll be able to get into in support of a research project at UH thats designed to date submerged shorelines on Oahu. (2) He wrote also:- > Since carbon monoxide binds about 200 times more readily to hemoblobin than oxygen, the partial pressure of the carbon monoxide may be irrelevant, because it is already having its maximum toxic effect at the surface. Is that it John? John R (NB: CO = carbon monoxide, O2 = oxygen, Hb = haemoglobin) If so, who isn't everybody on the surface dead from slow gassing by the inevitable small proportion of CO in modern urban air? No. Even if Hb-CO is bound far stronger than Hb-O2, yet there is an equilibrium concentration ratio of [Hb-CO] / [Hb-O2] / [unbound Hb] which varies according to the ppCO and ppO2. As ddoolette@me*.ad*.ed*.au* (David Doolette) wrote on Mon 25 Jul 1994 09:39:22 +0930 (Subject: Re: Risks of CO2 PP when air diving?), "... carboxyhaemoglobin [= Hb-CO] half-life in air is about 5.5 hours", i.e. far less than the life of a red corpuscle. And pressurizing the air to n bars increases its ppCO n times and so pushes the [Hb-CO] / [Hb-others] ratio a long way over. And with increase of depth pressure, the amount of oxygen carried dissolved in the blood plasma gradually increases so CO poisoning may show on surfacing rather than at depth, until e.g. mice in a high-pressure chamber may live on 20% O2, 80% CO (I read something to that effect once). That does not stop the CO from also perhaps acting as a narcotic at depth like N2 or N2O does. And, talking about `carbon mo`NOx'ious phew!!mes', whether from the air compressor's motor or from elsewhere, what is the effect of NO2 (nitrogen dioxide) in diving air, when compressed?
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