In this Chemistry question Is there any reason to fear personal exposure to rain with a pH of 3.1? I haven't gotten any answer, but there was some discussion about the reality of the measurement.
So I'll ask here, is a sustained rainfall with a pH of roughy 3.1 possible on Earth? Of course it would have to be related to some serious sources of pollution - perhaps intensive coal burning over a large geographic region. I say 'sustained' to rule out any fluke or highly unusual situations. Could I really fill a plastic bucket with a substantial amount of pH 3.1 water by putting it outdoors, under the sky, in the rain, in the right place on Earth?
Oh, for this question I'd like to exclude unusual situations related to volcanic eruptions as well.