Tell them that their smokeless breath when they exhale bothers you and hurts your feelings. Take photos of them breathing and wasting oxygen, which is what these people do in the world.
Where I live there's a mushroom plant, and mushrooms grow on manure, and then an animal rendering plant. Smelling tobacco smoke would be a nice change. Then when the farmers burn their fields, even though it's miles away it gives a very unpleasant haze that burns your eyes and smells like crap. I just take it as a fact of life.
Tell them that their smokeless breath when they exhale bothers you and hurts your feelings. Take photos of them breathing and wasting oxygen, which is what these people do in the world.
Those folks truly suck, and sorry for your predicament. However, it ain't persecution! Annoying, unreasonable, shitty, lots of more colorful words, but I don't think you can accurately say you're being persecuted. Well, I sure hope not!
The devil's advocate view: While I don't like the idea of not having somewhere to smoke, it sounds more like a property owner enforcing what type of activity is happening on private property. I'd be upset if my right to regulate activity on my private property were infringed on...