LordXenophon commented on spa's file in Gameplay Mods
In the real world, pollution from traffic is good for crops, at least ever since we got the lead out of our gas. All the air polution that's bad for crops comes from industry and garbage.
Orchards grow especially well next to highways, due to the densly packed trees competing for CO2.
What this mod should really do would be to make traffic desirable for farm land, but make water pollution, radiation and industrial polution a bad thing. You might also want to find a way to make crops reduce air polution, especially if the crops are orchards.