This study addresses the synergies of mitigation measures to control urban air pollutant and greenhouse gas (GHG) emissions, in developing integrated "co-control" strategies for Mexico City. First, existing studies of emissions reduction measuressPROAIRE (the air quality plan for Mexico City) and separate GHG studiessare used to construct a harmonized database of options. Second, linear programming (LP) is developed and applied as a decisionsupport tool to analyze least-cost strategies for meeting cocontrol targets for multiple pollutants. We estimate that implementing PROAIRE measures as planned will reduce 3.1% of the 2010 metropolitan CO 2 emissions, in addition to substantial local air pollutant reductions. Applying the LP, PROAIRE emissions reductions can be met at a 20% lower cost, using only the PROAIRE measures, by adjusting investments toward the more cost-effective measures; lower net costs are possible by including cost-saving GHG mitigation measures, but with increased investment. When CO 2 emission reduction targets are added to PROAIRE targets, the most cost-effective solutions use PROAIRE measures for the majority of local pollutant reductions, and GHG measures for additional CO 2 control. Because of synergies, the integrated planning of urban-global cocontrol can be beneficial, but we estimate that for Mexico City these benefits are often small.

Complex sociopolitical, economic, and geographical realities cause the 20 million residents of Mexico City to suffer from some of the worst air pollution conditions in the world. Greenhouse gas emissions from the city are also substantial, and opportunities for joint local-global air pollution control are being sought. Although a plethora of measures to improve local air quality and reduce greenhouse gas emissions have been proposed for Mexico City, resources are not available for implementation of all proposed controls and thus prioritization must occur. Yet policy makers often do not conduct comprehensive quantitative analyses to inform these decisions. We reanalyze a subset of currently proposed control measures, and derive cost and health benefit estimates that are directly comparable. This study illustrates that improved quantitative analysis can change implementation prioritization for air pollution and greenhouse gas control measures in Mexico City.