@Robert Engleheart,
Cant answer to the UV deterioration of Permethrin.
You have to dry the Permethrin completely, after spraying onto gear and fabric. For a time, maybe 1 or 2 washings, there is a smell but it is not unpleasant to me. Permethrin infused clothing is said to last 10 wash cycles. That is what I have found too.
Sawyer Spray on Permethrin is available at Walmart. You can also buy it at the feed store and mix it yourself which is what I do. Sawyer supplies our armed forces with the spray.
Dont treat your clothes around Cats or Dogs. Until it dries, Permethrin is deadly to them, if ingested.
I am sure that if you get your treated gear wet in a lake or river, it is toxic to fish, so keep that in mind. Wet wading in treated shorts for instance would be where that would come into play. Falling in with a treated shirt would be another scenario.
As mentioned before, since I started using the stuff, ( 10 plus years ), I have not had a Tick embed in me. Sleeping in my Treated Hammock, without using a bug net, I have not been bothered by Mosquitos.
Have a good Holiday all.
Bob