This year has been one loooong fire season in Montana and a lot of Western states. Brutal.
I'd made up some refrigerator tea with mullein leaves, chamomile, mint, and rose hips to be a mild, soothing tonic and probably need to make up some more.
Today, thanks to a friend, I ran across this article, which is a huge list of herbal resources in this regard. I highly recommend it. Way down in the comments, another herbalist chimes in that he thinks plantain is good for stressed lungs, too.
Prevention of and Herbal Therapeutics for Wildfire Related Smoke Inhalation
What is your favorite herbal tonic for respiratory distress?