The challenge derives from the fact that an individual commuter in metro Atlanta is capable of eliminating a full ton of atmospheric pollutants simply by using an alternative commuting method once per week. The average round-trip commute distance in Atlanta is 40 miles.
The challenge stems from the fact that a person commuting in Atlanta can reduce one ton of air pollution by choosing a different method for their weekly commute.  The typical round-trip commute in Atlanta is 40 miles long.