Located in a high Andean valley, Ecuador's capital city suffers from severe air pollution, emitted by manufacturing plants as well as motor vehicles. Improving air quality would result in diminished respiratory illness, which currently costs Quito's residents several millions of dollars annually in lost earnings and medical expenditures. Technology transfer has succeeded in reducing industrial emissions at a modest cost. But diesel-fueled trucks and buses, which are a major source of various pollutants, have been the primary focus of the local government's strategy for air quality improvement. To date, that strategy has met with some success, although future initiatives will involve higher abatement expenses and therefore will test the commitment of municipal authorities and the citizens they represent to pollution control.