Other posters have given good advice for using the plug-in nebulizer.
I also recommend getting a portable battery-powered nebulizer.
The one I use (and have for over a dozen years; I am on my second and now have the newer model) is an Omron MicroAir. Not cheap, but it fits in one's hand and runs off of 2 AA batteries. It can also be plugged in if one wishes. The catch is that it is an ultrasonic nebulizer and some meds (esp some CF meds) can't be used in it. However, Ventolin/salbutamol is fine in it. Over the years I have used it on city buses, airplanes, in the car, at work, and while out and about in all kinds of places. it is nearly silent, so the noise doesn't bother other people.
Another good portable model, cheaper but a bit bulker than the Omron, is made by Pari. It is a compressor, so it uses the traditional nebulizer cup (but Pari makes some excellent ones under their own brand that are much more efficient and faster treatment times than the cheaper ones that come with many low price traditional nebulizers). Note for this one that it is often sold with the battery as an optional extra, so if one does purchase it, making sure one actually is buying the battery with it is important.
One of the advantages of a portable nebulizer is that you can carry it with you which means you can use it just about wherever you are when you need it.
That said, during my first adult trip to WDW in 1998, I had the older version of the Omron and I needed to use it at Epcot. I used my inhaler and then took myself to the First Aid station where I sat in the quiet AC to use the nebulizer.
Even the bulky plug-in kinds they have now are SOOOOO much better than the
13 pound very bulky compressor I had to carry to and from school for almost all of high school.
-SW