# Carbon Monoxide **URL:** \ **Category:** Factual Questions\ **Created:** [June 26, 2016, 8:48pm UTC](https://boards.straightdope.com/t/carbon-monoxide/758443 "2016-06-26T20:48:31Z")\ **Posts on this page:** 4\ **Page:** 2
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [June 29, 2016, 5:54pm UTC](https://boards.straightdope.com/t/carbon-monoxide/758443/21 "2016-06-29T17:54:29Z")
> [@ftg](#): > > The good news: It takes an atom from 02 to form CO2. The bad news is the spare O joins with O2 to form O3: ozone. CO is a significant cause of ozone pollution in urban areas. Can’t be very good happening in the bloodstream either I’d imagine … ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [June 29, 2016, 6:31pm UTC](https://boards.straightdope.com/t/carbon-monoxide/758443/22 "2016-06-29T18:31:23Z")
> [@Machine\_Elf](#): > > The difference is that a high concentration of CO2 produces very unpleasant sensations and compels you to seek fresh air; try holding your breath for a while and you’ll feel what I mean. This is why suicide-by-plastic-bag-over-head generally also requires a strong sedative i.e. to ensure that the victim does not try to remove the bag. I had never really thought this through before, but if someone tries this with a modern car that doesn’t make as much CO, will the compulsion to seek fresh air cause him to end the attempt before the little bit of CO does much damage? ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [June 29, 2016, 6:31pm UTC](https://boards.straightdope.com/t/carbon-monoxide/758443/23 "2016-06-29T18:31:25Z")
> [@Isilder](#): > > What will happen is that O2 decreases in the air, the incorrect burning will occur, and the CO is produced. Late-model cars can idle just fine with rather limited O2 intake. At the top of Pikes Peak, for example (14,000+ feet above sea level), the air density about 60% that of sea level. The electronically controlled throttle will open further as necessary to assure enough oxygen is admitted to burn the amount of fuel required to maintain idle RPM. CO2 will build up to problematic levels before the O2 level drops far enough to compromise combustion. Ultimately the CO2 will compel you to seek fresh air (see my post just a few above this one). > [@Isilder](#): > > Anyway the engine is turned to run when driving and at idle it may run very poorly and ungreen. especially its not keeping the Cat convertor hot enough to work ? Cold-start emissions can be high, but the cat warms up pretty quickly. The light-off temp for a 3-way cat is about 250C, and idle exhaust temperature is generally around 350C, so tailpipe CO emissions should go low (and stay there) once the engine is warmed up, even if idling for extended periods. TL,DR: for a late-model car, CO2 buildup in the garage is likely to compel you to leave before the CO kills you. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [June 29, 2016, 10:32pm UTC](https://boards.straightdope.com/t/carbon-monoxide/758443/24 "2016-06-29T22:32:48Z")
> [@zwede](#): > > So what is the issue in a closed garage? The reaction is not quick enough allowing too much CO to build up? Or does the reaction require sunlight? The latter I understand; ozone is one of [several](https://en.wikipedia.org/wiki/Smog#Photochemical_smog) components of smog created by pollutants interacting with the ultraviolet in sunlight. [Previous page](https://boards.straightdope.com/t/carbon-monoxide/758443.md?page=1)