So I'm really not a car person, and could use some help here. Yesterday I had a toddler with me. I parked the car, and ~1 minute later we were behind car. I realized exhaust may have been close to the child so I peeked under the car. Sure enough, there was the exhaust (head was still behind car frame, barely, but quite low to see exhaust). I guess I'm wondering if it's bad that ~1 min after car was off, I looked under the back of car. How quickly do fumes dissipate anyway? Thanks!
The fumes dissipate very quickly. What's more, the exhaust of a modern (warmed up) car is far less toxic than it was a few decades ago. If you were driving slowly as you parked the car, the engine may have been off anyhow. Don't worry. - Chris
Thanks Chris. One more thing to add - we were parked for ~5-10 minutes before I turned car off. The AC was on though so there's a chance the engine kicked in at points...
I think you're fine. I have occasionally backed my car into the garage, shut it off and slid under the back on a rolling creeper. And there's nothing wrong with me. Just ask my toaster; she'll tell you.
Hot parts is the main issue as per Rebound. CO monoxide in exhaust is very low and no concern after car is off. You are mostly getting CO2 and water (like when you breath).
The OP wasn't what I was expecting from the question posed by the title. As others have mentioned, your greatest risk of harm is from the hot exhaust system. Any toxic emissions from the tail pipe are in such small quantities that these aren't even significant. You would have to be in a confined space with little air circulation for an extended period of time. The amount of time depends on the vehicle and condition of catalytic converter, but is going to be quite a bit longer than 5 - 10 minutes. Here's a link for more info: CDC - Immediately Dangerous to Life or Health Concentrations (IDLH): Carbon monoxide - NIOSH Publications and Products You can note that the one publication for humans shows 4,000 ppm for 30 minutes --- that's way more than a Prius is going to pump out in a garage.
