National Telecommuting and Air Quality Act - Directs the Secretary of Transportation to make a grant to a nonprofit private entity (specifically, the National Environmental Policy Institute, if it applies) for the purpose of developing a design for a proposed ozone precursor credit-trading pilot program in which: (1) methods would be evaluated and developed for calculating reductions in emissions of ozone precursors (air pollutants) that can be achieved as a result of reduced vehicle-miles-traveled (VMTs) by telecommuting employees; (2) regulated entities would present emission credits to the Federal Government or to the State (as applicable under the Clean Air Act) and the amounts of reductions in emissions of air pollutants represented by such credits would be for purposes of compliance with the Clean Air Act; and (3) the Federal Government would explore means to facilitate the transfer of emission credits between participating employers and regulated and other entities. Sets forth recommended sites for the operation of such pilot program, including: (1) the greater metropolitan region of the District of Columbia (including areas in Maryland and Virginia); (2) the greater metropolitan region of Los Angeles, California; and (3) three additional areas to be selected by the Secretary.

Directs the Secretary to require the grantee to study and report to Congress and to the Secretary on the potential significance of the proposed pilot program as an incentive for expanding telecommuting and reducing VMTs in the geographic areas, and the extent to which it would have positive effects on national, State, and local air quality and energy conservation and consumption. Authorizes appropriations.