title: Study of the regional air quality south of Mexico City (Morelos state).
abstract: Results from the first study of the regional air quality in Morelos state (located south of Mexico City) are presented. Criteria pollutants concentrations were measured at several sites within Morelos in February and March of 2007 and 2009; meteorological data was also collected along the state for the same time periods; additionally, a coupled meteorology-chemistry model (Mesoscale Climate Chemistry Model, MCCM) was used to gain understanding on the atmospheric processes occurring in the region. In general, concentrations of almost all the monitored pollutants (O(3), NO(x), CO, SO(2), PM) remained below the Mexican air quality standards during the campaign; however, relatively high concentrations of ozone (8-hour average concentrations above the 60 ppb level several times during the campaigns, i.e. exceeding the World Health Organization and the European Union maximum levels) were observed even at sites with very low reported local emissions. In fact, there is evidence that a large percentage of Morelos vegetation was probably exposed to unhealthy ozone levels (estimated AOT40 levels above the 3 ppm h critical limit). The MCCM qualitatively reproduced ozone daily variations in the sites with an urban component; though it consistently overestimated the ozone concentration in all the sites in Morelos. This is probably because the lack of an updated and detailed emission inventory for the state. The main wind patterns in the region corresponded to the mountain-valley system (downslope flows at night and during the first hours of the day, and upslope flows in the afternoon). At times, Morelos was affected by emissions from surrounding states (Distrito Federal or Puebla). The results are indicative of an efficient transport of ozone and its precursors at a regional level. They also suggest that the state is divided in two atmospheric basins by the Sierras de Tepoztlán, Texcal and Monte Negro.
authors.affiliation: Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Av Universidad 1001, Col Chamilpa, 62209 Cuernavaca, Mexico. dara.salcedo@ciencias.unam.mx
authors.forename: D
authors.initials: D
authors.lastname: Salcedo
authors.forename: T
authors.initials: T
authors.lastname: Castro
authors.forename: L G
authors.initials: LG
authors.lastname: Ruiz-Suárez
authors.forename: A
authors.initials: A
authors.lastname: García-Reynoso
authors.forename: R
authors.initials: R
authors.lastname: Torres-Jardón
authors.forename: A
authors.initials: A
authors.lastname: Torres-Jaramillo
authors.forename: B E
authors.initials: BE
authors.lastname: Mar-Morales
authors.forename: A
authors.initials: A
authors.lastname: Salcido
authors.forename: A T
authors.initials: AT
authors.lastname: Celada
authors.forename: S
authors.initials: S
authors.lastname: Carreón-Sierra
authors.forename: A P
authors.initials: AP
authors.lastname: Martínez
authors.forename: O A
authors.initials: OA
authors.lastname: Fentanes-Arriaga
authors.forename: E
authors.initials: E
authors.lastname: Deustúa
authors.forename: R
authors.initials: R
authors.lastname: Ramos-Villegas
authors.forename: A
authors.initials: A
authors.lastname: Retama-Hernández
authors.forename: M I
authors.initials: MI
authors.lastname: Saavedra
authors.forename: M
authors.initials: M
authors.lastname: Suárez-Lastra
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis*; D002947:Cities; D004784:Environmental Monitoring / Q000706:statistics & numerical data*; D005843:Geography; D008800:Mexico; D008956:Models, Chemical; D010126:Ozone / Q000032:analysis* / Q000737:chemistry; D052638:Particulate Matter / Q000032:analysis; D014887:Weather; D014919:Wind
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D010126:Ozone