different brands of pla do seem to have different 'smells'.
I was using one the other day that really did smell like maple syrup.
Mostly I don't detect any noticeable odour.

So if you're reacting or allergic to one brand of pla - try others.

You don't actually need or want an airtight enclosure.
A basic box with holes at the bottom and a fan exhaust to tumble dryer ducting that goes out the window is what you need.

That ways you are maintaining airflow over the machine and the print - keeping it from overheating, but also removing any fumes from your workshop.

So some cheap plywood/maf/fibreboard - 3-5mm would be fine. Some 100mm ducting, couple printed adaptors and one of these: https://www.amazon.co.uk/calimaero-I...3840175&sr=8-6

It's all about maintaining negative air pressure around the printer - so that the airflow is into the print volume and out of the room.