Comparative aerosol studies of Pacific rim cities—Santiago, Chile (1987); Mexico City, Mexico (1987–1990); and Los Angeles, U.S.A. (1973 and 1987)

The UC Davis Air Quality Group has performed studies on urban air quality since 1973. Recently, with the active collaboration of scientists in Mexico and Chile, these studies have been extended to other Pacific Rim cities of similar climate. From such comparisons, the successes (and failures) of control strategies can be inferred and compared to Los Angelesʹ progress, 1973 through 1987. An early and rather surprising result is the rough equivalence between Los Angeles, Mexico City, and Santiago in terms of several classes of fine (Dp < 2.5 μm) particles. However, coarser particles are far more prevalent in Mexico City and Santiago than Los Angeles. Finally, in many ways, Los Angeles of 1973 was worse than Mexico City and Santiago today. Thus, the progress of Los Angeles gives hope for similar improvement given suitable policies.