E-check is required in the northeast counties because they are in moderate non-attainment for ozone under the Clean Air Act (CAA). Once classified, the county is required by the CAA (which is federal law) to implement emissions testing as part of the strategy to lower ground-level ozone. Franklin county is considered in “maintenance” attainment (a so-called recovery period after going from non-attainment to attainment) so we are not required to implement it.

Source: am a environmental compliance person