Air is generally better in the country because there is less traffic and other emissions. Unless you are close to a power plant or farm spraying operation. Atlanta has an air quality index and warnings are issued when the AQI veers from good/moderate to unhealthy and very unhealthy. Because we have lots of traffic, air quality becomes a problem particularly in the warmer months when smog forms.
I can see the difference in air quality when I walk outdoors – just look at the lichens. Lichen is a combination of fungus and algae, usually forms on trees or downed branches and trunks and is very sensitive to air quality. For my purposes there are three basic types – a) the crusty version (crustose) which can tolerate poor air quality; b) the leafy type with lobes (foliose) which can tolerate moderate air quality; and c) the one with the little bushes (fruticose) which only survives where the air quality is good.
No surprise that in Atlanta I only see the crustose version, even when I go north to the Kennesaw Mountain National Battlefield Park where there are excellent running trails.
But head further north to the foothills of Appalachia to my little place, and there it is.
Wouldn’t it be nice to have good air quality where we live and exercise.