Mailvox: book assistance

AA is searching for a book:

In the 1970s, I read a dystopian novel that I’d like to find again. It was one of the First wave of “Eco-Disaster” novels, I think. The only things I remember are everybody wearing filters on their mouths, so they could avoid breathing in (and possibly killing) gnats and bugs, and a version of the Model T Ford being the only “allowed” form of transport.

The Characters used the Model T to get to and from some “Quasi-Religious” meetings that took place in the forest. Thin info, I know. I remember it as being a depressing, and sad book. That said, I’d really like to find it and read it again.

Do you have any Idea what it might be. Maybe someone in the Dread Ilk might have a Clue?

No clue. I’m sure I never read anything like that. Anyone among the Dread Ilk recognize his description?