Maricopa County, Arizona is a non-attainment area with respect to the NAAQS for carbon monoxide and particulates. The Governor's Air Quality Strategies Task Force established the Maricopa County Non-attainment Area Fuels Subcommittee, charged with recommending options for modifying the formulation of Winter gasoline and diesel fuel (year-round) consumed in Maricopa County so as to reduce CO formation in the County in the Winter season and particulates formation year-round.

The Arizona Department of Environmental Quality (ADEQ) selected MathPro Inc. as prime contractor on a team providing analytical support to the Subcommittee. In particular, MathPro Inc. conducted a detailed technical and economic analysis of gasoline and diesel supply to Maricopa County. The analysis encompassed (i) identifying candidate gasoline and diesel fuel formulations; (ii) estimating the effects of each formulation on vehicle emissions; (iii) assessing the effects of each formulation on the gasoline and diesel distribution system serving Maricopa County, on vehicle performance, and on related factors; (iv) analyzing the technical and economic implications of producing each gasoline and diesel formulation in the refining centers that supply Maricopa County; and (v) analyzing the prospective implications of each diesel fuel formulations on the supply of non-taxed diesel fuel in Arizona’s mining regions. Results of the analysis informed the recommendations that the Subcommittee issued.