If you really want to continue to work with this client, I might suggest getting a health mask, something like this:



Face Mask

It may seem a little drastic, but really you can get an allergen face mask at a lot of places. And that's what you are dealing with, basically. It could be awkward, but you can call the client ahead of time and even discuss it with them: you really want to continue to work with them, you are having difficulty with the smoke, but you think this might be a good solution and that way you are able to continue helping them. Making light of it might help too.

Also, if you are able to make their appointments at a time that you would be able to change your clothes or even take a shower afterward it would help.

I would at least give that a shot, if you want to continue working with them. It could possibly make a difference [you can also get them in colors and patterns so it's not so sterile looking]