[mgh]

Cop found dead inside car in Greater Noida - The Times of India
Above story today prompts the question.
especially, I quote from the story

Kumar put the AC on and fell asleep in the car. As all the windows were closed, he was choked to death inside the car by the gas emanating from the AC, said a police officer.

Obviously, if the AC was on, the windows would be closed. If we were to believe the police officer, many of us would have choked to death long ago.

[Warwithwheels]

I think this topic has been discussed extensively in the following threads:

http://www.team-bhp.com/forum/techni...-monoxide.html

http://www.team-bhp.com/forum/shifti...death-car.html

http://www.team-bhp.com/forum/street...-accident.html

http://www.team-bhp.com/forum/indian...nside-car.html

[GTO]

My first guess was that the drunk cop choked on his own vomit. Nope, it's not as rare a cause of death as you think : Rockstars who choked on their own vomit

Thank you for posting those links, Warwithwheels! I have to admit to sleeping in the car sometimes, with the air-con on, and didn't have the slightest clue of potential danger. NEVER ever again. Check this post by Navingulia:

Originally Posted by navingulia

I have done pretty amount of research on this. Navin Gulia - Discover the infinity in you……

Carbon monoxide(CO) is formed by combustion in limited supply of oxygen/air. CO is tasteless and odourless. Haeting coils in car engines can generate CO once they get rusty and old. Carbon monoxide when inhaled and absorbed into the blood forms carboxy haemoglobin with the haemoglobin thus disabling th ability of hameoglobin in blood to carry oxygen. Blood circulates but doesnt carry oxygen to tissues. The tissues suffocate and die.
in sleep one dies silently but if one is awake one will feel exhaustion and nausea and would get restless and would open the door/window but in sleep one would die silent.

prevention
1. never sleep with car heater/ac on.
2. keep the fan vent open. dont recirculate the air.
3. carbon monoxide is lighter than air. if at all due to extreme weather you have to keep AC/heater on while sleeping in car, do roll down all windows by one inch so that the lighter CO can escape out of the car.
4. when on expeditions to mountains, high altitude areas or otherwise. The whole group shouldnt sleep same time in the car. keep an alarm and sleep in shifts. one person should be awake at all times and his duty should be to shake other occupants every half hour to check back on them.
It is always better to be safe.
Point number one stated above is best.

[SmartCat]

Recirculation should be used only within the city, where the drives are short anyway. On the highways, whether sleeping in the car or cruising on the roads, switching to external circulation is the right thing to do. Even if your AC doesn't spew out CO, the passengers in the car spew out CO2 when they breathe out - and both the gases make you feel sleepy and tired.

[pganapathy]

I guess he died of carbon monoxide/dioxide poisoning if the story the police state is to be believed.

The own vomit theory makes a lot of sense too.

At the end of the day, ensure you have fresh air coming into the vehicle and a way for the stale air inside the vehicle to get out.

[Warwithwheels]

Originally Posted by GTO

.....I have to admit to sleeping in the car sometimes, with the air-con on, and didn't have the slightest clue of potential danger. NEVER ever again. Check this post by Navingulia:

Am sure that atleast 90% of the readers out here, including me have done it some day or the other. Just that the duration of the sleep inside the car would vary on a case to case basis. And going by the incidents reported, not all of them seem to have been resting in the car for unreasonably long hours. That's a real shocker

Just wondering if this reasoning can be extended to Long distances AC buses or any other mode of transport where a large chunk of people are forced into a confined AC cabin for extended period of time (Read:Overnight). Or do they come equipped with the appropriate re-circulation mechanism?

[ByDesign]

Choking on one's own vomit isn't far fetched at all.

When you regurgitate in your sleep, it can be very very dangerous. You do NOT want that to happen, trust me. Just putting it out there, that if you ever find yourself way too wasted, and find yourself bringing up stuff in a horizontal position, try leaning either way and let it go over the side. It's a life or death situation in most cases.

I saw GTO's post, and immediately thought of putting a quick tip out there. Always better to be prepared in any situation.

Regarding the cop's story, a simple autopsy would prove the cause of death. But I'm sure they wouldn't want to throw that out in the media's face. I mean imagine "Drunk constable died on own vomit". That wouldn't really help the reputation of an already tainted force.

[mayankjha1806]

Will this happen only when the AC is set in recirculation mode or can it also happen when the AC is on fresh intake air mode? The best solution suggested is to keep a small slit open in windows so as CO flow out of the cabin, or alternatively do not sleep in the car with AC on.

Although not specifically in this case, could this also happen by Benzene released by dashboard especially in the Sun?

[rajeev k]

So making a practice to put the flow in recirculation mode if one wants to sleep inside the car and occasional mode switching while cruising on highways appears to be the to be followed norm.
Another doubt; what about room ACs?

[zaks]

He could also have been asphyxiated by lack of oxygen with all windows closed, who knows even the aircon might have leaked some refrigerant into the cabin during his sleep.

[ghodlur]

Thats some news to me. I have seen many a times drivers in our office car parking basement sleeping inside the cars with air con on. I need to immediately raise an hazard alert to bring it to the notice of mgmnt so that the issue can be collectively addressed to all drivers.

Is there a link where the actual issue is highlighted?in detail? Not the BHP links, cant show it to the mgmt guys.

[mgh]

Window ACs used to have an adjustable fresh air inlet. With the modern preference for split air-conditioners, that is not available.
Central air-conditioning systems have adjustable fresh air inlets. However, more the fresh air, more is the power needed, when the outside is hot. Stand-alone movie theatres tend to keep the fresh air intake low. So you tend to yawn when you come out at the end of the movie. Offices and malls use enough fresh air for obvious reasons.
In a home situation, fresh air enters whenever you open the door. The usual opening and closing of doors is enough to let in sufficient fresh air. Also, please remember that doors and windows in homes are not usually air tight.
In a car, unless there is leakage of exhaust gases into the cabin, there should not be a problem. Unless, someone revels in long non-stop runs on the highway, the carbon dioxide one exhales, cannot be an issue.

[Catalyst_delhi]

When the car is stationary , the fresh air recirc will not work as expected.
The fresh air recirc for most cars is in the place where the wiper and motor mechanism is. This is beside the bonnet. When the car is stationary the blowby gasses and small exhaust which leaks in the engine bay will get sucked in the fresh air recirc. It would be good if the engineers put the fresh air recirc near the mid of the car chassis... Back engined cars are lucky.

[amtak]

Can someone post some pictures to explain the same in a better manner? So, should we or should we not re-circulate air?

[MAS]

The risks of CO emulating from a Car's A/C is an eye opener. But i feel that, unless the exhaust fumes somehow get into the car, this will be difficult.

How does it work in long distance buses air-conditioned buses, example a VOLVO.