It's not necessary to clean the tubing - just keep it dry. Unlike Rosalynn, I would consider it a miracle if my nebulizer lasted 6 months - 6 weeks is usually my best - and new tubing comes with the neb, so I just replace it then.
As for mask-wearing, ever since diagnosed, well before Covid, I have worn one in dusty/windy conditions, whenever doing yard & garden work, and during bad-air or high allergy conditions. It never seemed odd to me as my brother (who is also my winter neighbor) wears one too. So does one of my MN neighbors - we have noticed more & more of the landscape guys around here doing it too.
I continue to use N-95 masks in the garden, but just wear my 3-layer cloth ones now for everyday use. I just came in from raking the winter leaf cover off the gardens, and will put on the N-95 before I begin loading the leaves into compostable bags.
Sue