In general yes. Lichen are certainly a positive sign in general for the health of local ecosystems.

Having said that, this particular genus seems highly resistant to pollutants - which is to say, it's presence wouldn't be a bad sign for the cleanliness of a local environment, but neither would it be definitively indicative of low pollution levels.

I heard Xanthoria species grow on rocks less readily overall, and perhaps with a preference to rocks regularly bathed in bird poop. Just a funny anecdote.