Danger of spending time inside a running, not moving car

[fog37]

TL;DR Summary

health danger of being inside a running car for a prolonged time while it is not moving

Hello Forum,

I am not sure this question really belongs here but I was not sure where else to post...it is about science and health after all. I started thinking about this question seeing so many people have sadly become homeless and living in their cars because of the pandemic and job crisis.

When a car is not moving and either the heating system (very cold outside) or the cooling system (very hot outside) is used while occupants are in the vehicle's cabin for long durations of time, CO poisoning from the exhaust fumes entering the car is a real danger and possibility with both new and old cars. Many people go camping, do road trips and often sleep in their cars. Truck drivers sleep in their trucks all the time.
But my understanding is that running the AC or the heat while being in the car is extremely dangerous and should never be done.

Cooling and heating can work in two modes:

a) Recirculating air mode: the air that is already inside your vehicle's cabin is continuously used. This mode seems to prevent the exhaust fumes and CO to enter the cabin. However, if we stay in the car for hours, the air we breath is depleted of oxygen, rich in CO2 and moisture and suffocation becomes a risk.

b) Fresh air mode: air is pulled from the outside and either warmed by the heating core or cooler by the evaporator. If the car is running and not moving, exhaust fumes are certainly pulled into the cabin and dangerous. This is not a problem when we wait at a traffic light for a few minutes but sleeping in the car for many hours is surely dangerous.

How about talking in the car (being awake) for a few hours running either the AC or the heat? It seems equally dangerous but being awake can surely prevent death.

Is my understanding correct? In summary, spending time in a running vehicle while it is not moving is very dangerous. I guess one option could be a battery operated electric heater to warm up with the car off when it is cold...

Thanks!

 

[hutchphd]

The air intake for cabin air is typically in front of the windshield. This should at least minimize the infiltration. I think a more important factor is likely rust holes in the exhaust system, cabin floor. and lower panels. It is a serious issue.
Being awake is no guarantee of safety because sleep is likely. The electric heater would require very large batteries: probably an impractical solution. A good sleeping bag is probably a better idea.
Of course the real question is: how can we as sentient beings allow this to happen to our fellows? There are no immutable laws that demand it .

 

[fog37]

hutchphd,

Thanks for confirming the danger of both running AC and heat while the car is not moving. Before reflecting on this, I think I may have sat in my car conversing with someone for longer than I needed. Many commuting students waiting to go to class take naps in the car, review class material, etc.

How to prevent these deadly situations? I feel like many people are either completely unaware of the issue while others think that it is only a problem with heating and not with using the AC for cooling. So there is lack of knowledge.

I don't think the driving license test mentions this possible issue. Maybe it should Car makers could maybe inform car buyers about this dangerous possibility? No sure...

 

[berkeman]

If you are concerned and have the freedom to pick which way you point your car when parking it, face into the wind. Also, consider getting a battery powered CO detector to put in your car's cabin. That will at least alert you if there starts to be a build up.

https://www.amazon.com/dp/B004Y6V6K4/?tag=pfamazon01-20

 

[pbuk]

But my understanding is that running the AC or the heat while being in the car is extremely dangerous and should never be done.

Do you have any authoritative reference for this?

 

[fog37]

Do you have any authoritative reference for this?

I don't have specific references at the moment.

I have been reading online about accidents that happened that way and I am looking at some statistics and more solid articles on the topic...

 

[pbuk]

If you are concerned and have the freedom to pick which way you point your car when parking it, face into the wind. Also, consider getting a battery powered CO detector to put in your car's cabin. That will at least alert you if there starts to be a build up.

Yeah, you'll be fine, its just the rest of the world that will have to suffer from your pollution

Emergencies including homelessness is one thing, but these aside there is no excuse for running a car engine while stationary to make it comfortable to sit in.

 

[fog37]

Yeah, you'll be fine, its just the rest of the world that will have to suffer from your pollution

Emergencies including homelessness is one thing, but these aside there is no excuse for running a car engine while stationary to make it comfortable to sit in.

Agree on the pollution factor.

So, pbuk, you don't feel like there is much of a safety issue otherwise to be in the stationary car running the AC or heat.

Thanks!

 

[berkeman]

Emergencies including homelessness is one thing, but these aside there is no excuse for running a car engine while stationary to make it comfortable to sit in.

Well, speaking from personal experience when "posting", our employers often require that we keep the vehicle engine running when posting in the field waiting for a call (ambulance, police vehicles, etc.).

 

[russ_watters]

hutchphd,

Thanks for confirming the danger of both running AC and heat while the car is not moving...

How to prevent these deadly situations?

I'm pretty sure @hutchphd did not confirm there was a serious risk, but rather was arguing that there isn't. I'll add my vote to that.

I have been reading online about accidents that happened that way and I am looking at some statistics and more solid articles on the topic...

Could you please post something you've found. I've never heard of anyone *ever* dying from CO poisoning while in a car, outside. I'm not saying it is completely impossible, but I am saying I think it is extraordinarily unlikely.

Also, while an unhealthy high level of CO2 is possible in re-circulation mode, death from CO2 poisoning in a car is essentially impossible.

 

[pbuk]

Well, speaking from personal experience when "posting", our employers often require that we keep the vehicle engine running when posting in the field waiting for a call (ambulance, police vehicles, etc.).

I don't think the reason they require that is so that it is comfortable to sit in though!

 

[fog37]

Ok, I will try to provide some references. I run into several news articles on this issue. Here the ones I just found:

https://gulfnews.com/uae/health/sleeping-in-the-cool-comfort-of-your-car-can-kill-you-1.1065303

https://theaseanpost.com/article/sleeping-cars-can-kill-you

 

[berkeman]

I don't think the reason they require that is so that it is comfortable to sit in though!

True, but it's a side effect. We try to park in the shade on hot days, and in the sun on cold days, but we still usually will run the AC or heater as needed to stay comfortable. I know that the police tend to need the AC more because of the hot uniforms that they are in (including the ballistic vest).

 

[256bits]

Ok, I will try to provide some references. I run into several news articles on this issue. Here the ones I just found:

https://gulfnews.com/uae/health/sleeping-in-the-cool-comfort-of-your-car-can-kill-you-1.1065303

https://theaseanpost.com/article/sleeping-cars-can-kill-you

No mention of an article of how many people die from the same issue in a running non-moving or slow-moving car in a traffic jam, which by the way can sometimes last for hours. It would seem that would provide better statistics of vehicle afflictions, including deaths, from non-moving running cars than those instances specifically picked for an article.

 

[fog37]

All fair points. Thank you.

I found this article on Google Scholar: https://ajph.aphapublications.org/doi/pdf/10.2105/AJPH.62.11.1463

Again, I am trying to create a false problem but just want to learn what is the right thing to do to be safer.

 

[tech99]

I believe modern vehicles do not emit CO, NOx and particulate as they have catalytic converters and also Diesel Particulate Filters. I read that a Volvo in California leaves the air cleaner when it came out than when it went in.

 

[pbuk]

So, pbuk, you don't feel like there is much of a safety issue otherwise to be in the stationary car running the AC or heat.

Please do not put words into my mouth.

I found this article on Google Scholar: https://ajph.aphapublications.org/doi/pdf/10.2105/AJPH.62.11.1463

That article is based on data that is 50 years old. From the conclusion to that article:

The deaths in this study can be divided into two main groups: 27 occurring in vehicles that were indoors and 51 in vehicles out of doors. The latter group is considered to be related to faulty vehicles, partly because lethal concentrations of CO could not otherwise be explained and partly because abnormalities were found in each vehicle that was examined.

I ... just want to learn what is the right thing to do to be safer.

I am not an expert on vehicle safety but I would suggest:

1. Ensure your vehicle is well maintained and frequently inspected.
2. Do not operate a vehicle if it is faulty or damaged.
3. Do not run the engine in an enclosed space or when air flow may be obstructed e.g. due to deep snow, or drive with the tailgate or boot/trunk lid open e.g. to accommodate an abnormal load.
4. Follow any local guidance from government agencies or reputable motoring organisations.

 

[berkeman]

I believe modern vehicles do not emit CO, NOx and particulate as they have catalytic converters and also Diesel Particulate Filters. I read that a Volvo in California leaves the air cleaner when it came out than when it went in.

I see that catalytic converters reduce CO and other problematic components of the exhaust, but I don't think they eliminate them, do they? Can you provide a link?

https://letstalkscience.ca/educational-resources/stem-in-context/catalytic-converters

 

[fog37]

Please do not put words into my mouth.That article is based on data that is 50 years old. From the conclusion to that article:
I am not an expert on vehicle safety but I would suggest:

1. Ensure your vehicle is well maintained and frequently inspected.
2. Do not operate a vehicle if it is faulty or damaged.
3. Do not run the engine in an enclosed space or when air flow may be obstructed e.g. due to deep snow, or drive with the tailgate or boot/trunk lid open e.g. to accommodate an abnormal load.
4. Follow any local guidance from government agencies or reputable motoring organisations.

Agreed. Sorry, didn't mean to extrapolate and put words in your mouth.

It may be more of an issue with older and defective cars indeed. Sometimes it can be hard to know if the car is truly in perfect conditions or not. I guess the accidents are not that many. I was looking around on the web and found this unfortunate story:

https://says.com/my/news/vacation-in-penang-found-3-dead-after-sleeping-in-car

 

[berkeman]

I see that catalytic converters reduce CO and other problematic components of the exhaust, but I don't think they eliminate them, do they? Can you provide a link?

So, being a Medic (part time as my EE job allows), I did a search on whether the introduction of catalytic converters on cars significantly cut the ability of folks to use cars in garages to commit suicide. I expected to find something where attempted suicides were thwarted by the new technology, but that's not what I found with my search.

I'll enclose the search results in spoiler tags, since they may be disturbing in addition to being surprising.

Spoiler

https://www.mja.com.au/journal/1998...converters-motor-vehicle-exhaust-gas-suicides

Conclusion: Catalytic converters and the associated lower CO emission limits of 9.3 g/km had not, by 1995, resulted in a reduction in numbers, rates or percentages of exhaust gas suicides in Australia.

 

[Tom.G]

Way back when I was a teenager, a friend signed-up for the Navy. I was between cars at the time and he loaned me his while away.

One night a mutual friend and I were on a long drive in the country. I was getting sleepy and stayed awake by closely following a large truck that was on the road. Eventually the truck turned off to a side road. My friend had crawled into the back seat to take a nap. I decided to wake him up to help keep me alert. No dice, he wouldn't awaken.

I realized there was something wrong, probably Carbon Monoxide. I opened the front windows. I started feeling better and the guy in the back seat woke up.

After the car owner returned from military service I returned the car to him with a warning about CO2 and a probable exhaust leak. A few weeks later the car was totaled but the owner was OK. He had run into a barricade on the interstate highway.

He wouldn't admit to anything.

Pay attention out there folks, it really does happen... and with the reduced Oxygen to the brain, you very well may not even realize there is a problem, at least the first time.

Cheers,
Tom

 

[256bits]

All fair points. Thank you.

I found this article on Google Scholar: https://ajph.aphapublications.org/doi/pdf/10.2105/AJPH.62.11.1463

Again, I am trying to create a false problem but just want to learn what is the right thing to do to be safer.

A false problem it is not.
You have mentioned some occurrences already.

I mentioned obtaining some statistics on cars, which could be available wholesale in the field immobilized in traffic jams.
That would tell if all cars - old, new, make, model, ... - have a tendency to increase the CO content within the cabin when not moving and running, and by how much.
A problem though, as that would entail people recognizing symptoms and reporting , which they probably would not do - they would probably attribute sleepiness with something such as boredom. Or, CO monitors placed within the cabin could record the ppm, but people would have to sign up. That might be difficult for a researcher to organize.
It's certainly not something that is sought out, nor provided, when purchasing a vehicle, either old or new.
Perhaps it should be.

CO, and with most cars exhaust being close to the ground at the rear, any entrance into the cabin, near or around the exhaust, or from faults from the engine compartment to the exhaust exit, could find its way inside.
Large trucks have the exhaust pipe exit above the cabin, so any wind would in most cases blow the gases away, rather than circulate them around the vehicle.

 

[fog37]

Thank you, good discussion. Very helpful.

I will continue to investigate and share recent relevant information as I find it...

 

[russ_watters]

I believe modern vehicles do not emit CO, NOx and particulate as they have catalytic converters and also Diesel Particulate Filters. I read that a Volvo in California leaves the air cleaner when it came out than when it went in.

That last bit is probably an exaggeration, but at my last job I did have access to a combustion gas analyzer, so for the heck of it I stuck it up the tailpipe of my car. My recollection is that the reading was single digits for CO. Yes, a properly functioning, modern car should produce almost no CO because that's a sign of incomplete combustion.

So, being a Medic (part time as my EE job allows), I did a search on whether the introduction of catalytic converters on cars significantly cut the ability of folks to use cars in garages to commit suicide. I expected to find something where attempted suicides were thwarted by the new technology, but that's not what I found with my search.

Are autopsies usually done on people who die this way? Do we know for sure they are dying from CO and not CO2? Also, is a car's computer smart enough to deal with the car being suffocated? Maybe after it has sucked much of the oxygen out of the room, it starts producing more CO?

 

[Lnewqban]

Thank you, good discussion. Very helpful.

I will continue to investigate and share recent relevant information as I find it...

https://www.lifewire.com/avoid-carbon-monoxide-poisoning-in-car-4134877

https://www.abe.iastate.edu/extension-and-outreach/carbon-monoxide-poisoning-vehicles-aen-208/

https://hoganandsonsinc.com/blog/view/concerned-about-carbon-monoxide-in-your-car-here-s-what-to-do

https://www.cdc.gov/co/faqs.htm

 

[BigDon]

Last September my stepfather's next door neighbor "Tom" unfortunately contracted Covid and passed rather rapidly. When Pops went down the street and informed Tom's sister and brother-in-law, they were so afraid of leaving one or the other alone they did this.

And this really bothers me. I knew these people more than 45 years.

And the saddest part? Tom's widow is now truly all alone, with no living relatives.

 

[dlgoff]

I think a more important factor is likely rust holes in the exhaust system, cabin floor. and lower panels. It is a serious issue.

I agree. About got me one time.