It’s a great question.
If you’ve ever been into the house of someone who smoked for thirty years you’ll have an idea where it goes!
The co2 dissipates into the room, the water vapour does water stuff and the particulate matter settles onto surfaces and is absorbed by it.
For smoking this is a problem and it’s called “third hand smoke”. All the carcinogens sit on the material. They might slowly release back into the air when disturbed. They transfer to your hands which can transfer to your mouth.
I once knew a family who had a small house fire. Their toaster set alight. They didnt have a fire extinguisher and had to call the fire brigade. They took ten minutes.
In that time the toasters plastic started to melt and thick black smoke filled the house. Thankfully nothing else caught on fire and it was extinguished. But – a lot of their stuff was destroyed and needed replacing. The smoke contained all sorts of nasty weird plastic things that settled onto litterally everything. When it cools its next to impossible to clean. The inside of their TV was soot filled for example and they just had to replace it.
Another fun fact – this goes for everything you burn. You are just converting matter into particulate matter that goes into the atmosphere. That’s what air pollution is basically.
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