A new long-term plan to clean up the air in the Valley of Mexico calls for strategies that would cut emissions in part by reorganizing the way the city is structured and how people go about their daily business. Called Proaire, the nine-year plan is the latest installment in an effort stretching back two decades to improve air quality in the Mexico City metropolitan area, where almost 20 million people live. In that time, a mix of measures has succeeded in bringing some key pollutants—lead, carbon monoxide, sulfur dioxide and nitrogen dioxide—in line with Mexican emissions standards. But ground-level ozone and particulate concentrations have not eased fast enough and still exceed the standards for much of the year. At the... [Log in to read more]