It just needs flair. Here's a positive pressure suit that's sure to put a smile on your face, just add a HEPA filter.

https://smile.amazon.com/Rubies-Adult-Jurassic-Inflatable-Co...

Why would it be illegal?

Some places it is illegal to cover your face. (Banks, Government Buildings, etc...) I would probably put a "Hi my name is BLANK" sticker on my shirt to kinda offset that.

Inciting a panic, perhaps.

I fear for the overton window sometimes.

I'm not trying to get anything banned, but it's obvious that what you wear has an impact on the people around you. If you walk into a gas station with a ski mask and a pistol I'm pretty sure everyone around you is going to calculate what your next move is. Similarly if I see a group of people put on gas masks at the CVS, I'm going to be pretty scared. If I saw a dude in a full hazmat suit just casually walking around, I'd be terrified!

Why? Because hazmat suits are for, well, hazardous situations. Hazmat suits invoke thoughts of radiation, of deadly gas, of immense pain and long term disability. In short: they're scary, and wearing one could scare people. Thus, I figured they might already be banned in some areas.