Premature Mortality and Costs Attributable to Imported Primary PM2.5 from a Densely Urbanized Metropolis

Cross-state air pollution can degrade air quality in regions surrounding urban areas. However, assessing health impacts and economic costs requires quantifying annual pollutant transport. This type of annual assessment poses significant technical challenges, including the need to differentiate between external and local pollution, which have different spatial distributions; the large number of required air quality simulations; and the extensive post-processing of results. The Mexico City Metropolitan Area is located within the most polluted airshed in the country and exports large quantities of atmospheric pollutants to neighboring airsheds; however, until now, the annual magnitude of the impact on the population and its associated costs had not been quantified. This paper presents the estimation of potentially avoidable premature mortality and the annual economic cost associated with importing PM2.5 from the Mexico City Metropolitan Area into the metropolitan areas of Toluca and Cuernavaca. These estimates are based on 8640 simulations of air quality using the Hysplit 5.3.0 model, corresponding to each hour of 360 days in one year. Geoprocessing tools specifically designed in ArcGIS 10.4 were used to automate the calculations of PM2.5 mass exchange, and the premature mortality and health costs were calculated using the BenMap-CE 1.5.0.4 program. Results indicate that the export of PM2.5 from the Mexico City Metropolitan Area in 2018 may have resulted in 19,473 potentially avoidable premature deaths in the two recipient metropolitan areas. This impact could represent an annual economic cost of $12,197 million for the Toluca Valley Metropolitan Area and $4140 million for the Cuernavaca Metropolitan Area.