Catalytic converters vs. the danger of inhaling exhaust fumes?

“An oxidizing reaction converts carbon monoxide (CO) and unburned hydrocarbons (HC), and a reduction reaction converts oxides of nitrogen (NOx) to produce carbon dioxide (CO2), nitrogen (N2), and water (H2O)”

What is the net effect that catalytic converters have on the danger of inhaling car exhaust fumes?
I assume you can still die if you lock yourself in a garage with your post-1974 car running.

So, what about the statement above?
Does the CC simply REDUCE the amount of CO, but there is still a lethal amount that comes out?
Or does the CC eliminate all CO emissions making the whole car garage suicide a thing of the pre-1974 past?

A correctly-running modern car will kill you with CO2, not CO. Or maybe by lack of O2.

I am no chemist, but the way I understand it, catalytic converters, and unleaded gasoline, reduced pollutants that were getting into our water supply at an alarming rate before 1974.

The purpose of the catalytic converter is to reduce carbon monoxide and unburned hydrocarbons. Nothing can eliminate them completely except shutting off the car. I know this because my oxygen sensors tell me so.

So if you want to kill yourself quickly, use a pre-1974 car. A new car will still kill you, but it might take a couple minutes longer. In either case, you’ll be asleep before you kick the bucket, so it doesn’t really matter.

Motor car exhaust may have contained up to 25% carbon monoxide. However, catalytic converters found on all modern automobiles eliminate over 99% of carbon monoxide produced.

I have never heard of suicide via CO2. I do not think it is possible.

There is one site on a hemoglobin chain that can absorb an O2 molecule in the lungs and release the O2 in the body where the O2 concentration is low. Hemoglobin has a much greater affinity for CO than for O2 at the site; that is, a CO molecule can strongly bind to that site and prevent the site to pick up O2. In other words, one CO molecule means a loss of one hemoglobin molecule.

CO2, on the other hand, is basically inert and does not react with a hemoglobin molecule. If the CO2 completely replaces O2, then of course, the body will succumb due to the lack of O2. But CO poisoning is much more effective than CO2/O2 replacement.

There are better methods - consult your PCP.

The continued introduction of CO2, therefore the reduction, expelation, and continually reducing ratio of O2 , is how CO2 kills you.
The LACK of O2 as a result.
The resulting high ratio of CO2.

This is ‘‘crib death’’ too.
The baby is sleeping in such a trapped position so as to continually re-breathe their own CO2 exhalation to the point of saturation as there is no introduction of new O2 or too little too late :frowning:


Some other guys and myself were working on putting a cellar or basement if you will under an existing house-we were using an old Case Uniloader,gasoline powered and the choke was about half stuck shut and the motor was running rich.In just a little while we were sick and drowsy,ended up with a terrible headache-CO is nothing to trifle with,CO will burn its not completly oxidised(thats what the the old gasogen motors burned) thank God for catalytic converters,of course the new Diesel engines for the most part use Urea(diesel fluid to breakdown the NOX) This may be a stupid question but what does the nitrous oxide hurt?-Kevin

The reason I asked this question in the first place?

When riding a bicycle alongside traffic, is this dangerous to inhale?
What about people who live on the ground floor next to a busy street?

Is breathing safe when there is plenty of ventilation?

It’s safe (much safer than the danger from getting hit by a car, that’s for sure). Except in very polluted (typically 3rd world) places.

In the early 1970’s, CO levels in many U.S. cities was reaching the danger point…There were days in Los Angeles when driving bans had to be put into effect to avoid lethal air quality…Denver was in a similar situation…Something had to be done…Preventing garage suicides was not the issue but as it turns out, that method of pulling the plug is seldom used any more because it simply is not effective…

But lets face it, air is simply not the same after it has been pumped through a piston engine or turbine. Busy streets are not the place to find pristine air quality…

Right, but you’re not going to pass out from riding a bike in traffic, correct?

I’d wager that in some cities the car exhaust is probably cleaner than the air going into the car.

The amount of carbon monoxide that comes out of the tailpipe in modern cars has been dramatically reduced from the cars of yesteryear, but it has not been completely eliminated. And carbon dioxide will sufficate you too. That is exactly what kills you if you place a plastic bag over your head…the carbon dioxide replaces the oxygen.

The dissipation rate is so great that there’s no breathing problem in those scenarios.

In the open, it would be very hard to get enough CO to give you more than a headache, unless you put your face near the tailpipe. You will still kill yourself just as dead as you would in the '70s if you run your car in a closed garage. It may take a little longer than with cars of yesteryear, but the CO will still get you. And as the exhaust fumes build up, the car will run less and less efficiently and produce more and more CO and other toxic waste products. Any combustion except for the combustion of pure hydrogen will produce some carbon monoxide as a waste product. The more carefully controlled, the less, but we haven’t gotten to the point where we can burn anything with complete efficiency. As others have said, combustion uses up the oxygen in the air in an enclosed space. So whether you suffocate from lack of oxygen or CO poisoning, it will still kill you.

Certainly catalytic converters and modern computer controls do an amazing job of cleaning up tailpipe emissions. You can really tell the difference just with your nose being behind a modern car and a car from the 1970s or earlier. I can smell unburned hydrocarbons if I’m behind any gasoline-powered vehicle that doesn’t have a catalytic converter or isn’t running right.

People of my grandarents’ generation had a serious distrust of natural gas. They remembered the dangers of coal gas and didn’t trust having any gas in the house. Coal gas is high in CO and many people died of exposure. Nothing to do with cars, but those stories gave me a respect for the lethal potential of carbon monoxide.