Here in the Southern Appalachians we get bad air transported from points SW and NW of us. Atlanta shares their mess with us as do the coal plants in the Tn. and Ohio valleys. When the winds blow consistently from those directions and we don't get regular thunderstorms to scrub it clean we get orange conditions in both ozone and particulates. The high ridges are much worse than the valleys because the lower elevations are mostly local source. I avoid orange days though it is rare to have those conditions everywhere in the area at the same time. I can usually ride either in the valley or up on the mountain in green conditions though it will always be cooler up at higher elevations.