Corinne, welcomes. I think Rob has something there, bringing a vehicle close to the hives would be great, but I am too lazy for that. I bit that bullet and purchased a small 12 volt car battery. I think it was $60 or something, but I figured that I would be using it for many years so it would pay for itself with peace of mind that I KNOW my bees have help anytime I need to vapourize.
My wonderful Husband made me some very long leads that I attach to the battery out of wire that he got from a car parts place, 14 guage wire, to be exact, used for car stereos, but other wire can also be used. I can pretty much leave the battery in one spot or move it slightly, I think the leads are about 15 feet long.
The thing with vapourizing is: (others also vapourize with acetic acid (vinegar) with good results I have heard, but I don't know about that, there is talk on our forum of this in other threads) -- it is not like many other applications.
Oxalic acid when it is made into a sugar syrup trickle MUST only be done when there is no brood present in the colony. I.e., wintertime, because it can kill brood. Vapourizing can be done any time there is a necessity, it does not kill bees nor brood. But, I would not do it during the honey flow regardless, only before, in the spring or in the fall. The vapourizing in the spring should keep the mites in good check until the fall treatment. There will be mites in the summer I would imagine, but not bad enough to affect them deeply, until their fall treatment.
There are other methods that work well too. That powdered sugar dusting, but I am too lazy for that, and the regression to small cell. I have no intention of this either. That is me. I hope this has been explained a little deeper and better for you. Beautiful and most wonderful day, lovin' this life we live, enjoy your day like there was no tomorrow. Cindi