Air Quality in the Mexico Megacity February 2002 HKS Authors See citation below for complete author information. Arnold Howitt Adjunct Lecturer in Public Policy Citation Howitt, Arnold, and Ralph Gakenheimer. “The Mexico City Metropolitan Area Transportation System: Mobility and Air Pollution.” Air Quality in the Mexico Megacity. Ed. Luisa T. Molina and Mario J. Molina. Kluwer, February 2002.