Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: paul.fr on 08/04/2007 01:22:05
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Just noticed that my brand of cigarettes contain 8g carbon monoxide. Assuming this is released in to the air from the smoke/burning, if i was locked in an air tight room. How many cigarettes would i have to smoke before i suffered CO poisoning? Or would a different chemical get me first?
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Geesh Paul kick those things to the curb!! That sounds scary!
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Geesh Paul kick those things to the curb!! That sounds scary!
yes it does sound scary, but is it? I think it gets in to the blood, but have no idea about the airbourne effects.
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I don't know my mom died from lung cancer she was a chain smoker. I was around it my whole life My grandmother too. we used to roll her cigarettes for her with the little hand crank roller! Yucky stuff! Both of them with lung disease!
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CO is a product of incomplete burning or organic matter.
I would guess that the 8g (sounds an awful lot - how much does a cigarette weigh in total - are you sure it is not 8mg?) is caused by insufficient air being drawn through the compacted cigarette that causes incomplete burning.
If you are in a seeled room, you will start to use up the oxygen in the room as you burn the cigarette (it would be the same if you burn a candle in a seeled room), so you will have a combination of ever less oxygen to breath, and as you have less oxygen for yourself so too you will have ever less oxygen to feed the flame, and so ever more incomplete burning, and ever more CO being produced where you previously had CO2.
You should never burn anything in a seeled room that contains you within that room, no matter whether it be a cigarette, or anything else.
The same thing happens if you have a poorly ventilated gas fire - lots of carbon monoxide produced because there is not enough oxygen available for complete combustion to produce carbon dioxide (which, ofcourse, requires twice as much oxygen as carbon monoxide).
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CO is a product of incomplete burning or organic matter.
I would guess that the 8g (sounds an awful lot - how much does a cigarette weigh in total - are you sure it is not 8mg?)
you are correct, George. 8mg not 8g...i blame my key pad [;)]
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Wow I guess that is a good reason to have a carbon monoxide detector in place! (which I do as I have Wood heat and also love candles) I keep batteries fresh and have never had to hear the thing sound off although I know it works as I test it regularly.
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Well, obviously the cigarette does not "contain" the 8 mg of CO while in the package, so this begs the question, what is meant here by "contains 8 mg of carbon monoxide"?
Several possible interpretations are immediately obvious (in order of increasing harm):
1) 8 mg of CO are released to the atmosphere per cigarette
2) 8 mg of CO are inhaled per cigarette
3) 8 mg of CO are actually absorbed by the body per cigarette
Note that #2 and #3 are not identical, since most of the CO inhaled would be lost with the next inhalation. In my opinion, #2 is the most likely interpretation.
To go with the first interpretation (your question), start a threshold value for CO toxicity. The LC50 (the concentration at which 50% of rats die within an hour) is 3760 ppm, while permissible exposure levels are 25-50 ppm.
You didn't say what size room, but I went ahead and used a 3m x 3m x 3m room (about 10' x 10' x 10') to get a volume of 27,000 liters. Using the ideal gas law, I calculated an approximate mass of air of 32.4 kg of air (about 71 pounds).
Using the LC50 of 3760 ppm, you would have a 50% chance of dying when there was 12.2 g of CO present (~15000 cigarettes).
Using an occupational lower limit of 25 ppm, that's 795 mg of CO (~100 cigarettes).
For case #2 above, the calculation becomes more difficult, since the CO is produced over the lifetime of the cigarette, and some of the CO that gets inhaled in one breath gets exhaled in the next breath. The more breaths per cigarette, the less CO stays in your lungs. Also, holding your breath (or less frequent breaths) allows more time for the CO to be absorbed into the blood, where it will stay for quite a while.
However, with a lung capacity of about 6 liters (less for a smoker), and assuming that 3/4 of the CO gets into and stays in the lungs during the lifetime of the cigarette (pretty arbritrary on my part), gives 6 mg of CO in 6.8 g of air, which is almost 900 ppm. Take that 6 mg number with a large grain of salt, since there are many unknowns here. The average person apparently cycles about 8% of the lung capacity per breath, but the exhaled breath is probably richer in CO than the air remaining in the lungs. What is certain is that the CO level would peak at the end of the cigarette and decline fairly rapidly after that, unless you light up another cigarette (as with chain smokers).
Dick
references:
1) The lung volume and exchange volume information were pulled from Wikipedia.
2) The CO toxicity information were taken from an online MSDS from Scott Gases.