it's important for us to have intercomparison. in fact, some of the measurements during the campaign were designed exactly for that purpose. narrator: long-term, milagro will lead to better models of how emissions are transported and transformed, helping countries manage and improve air quality. preliminary data show that the aerosol plume from mexico city travels outside the city and rises high into the troposphere. here, the prevailing high-altitude winds can potentially transport the pollutants long distances, even across continents. but it will be many years before molina and her team have definitive results. molina: milagro -- right now we only finish the first phase one, the measurement, the observation stage. and then the next phase is now we are in the process of doing the data analysis so we have all of this tons and tons of data. then all this information are now fit into models. then we are going to present the results to the mexican government. narrator: while the mexican government has recently made strides in reducin