Wet Deposition Fluxes and Related Atmospheric Chemistry at Three Sites in Mexico

Abstract

Wet deposition was collected in Mexico City (MC), Metropolitan Area of Monterrey (MAM) and El Chico National Park (ECNP), during 2009 and 2010. pH, conductivity, Cl − , 2 4 SO − 3 NO − , 4 NH + , Na + , K + , Ca 2+ and Mg 2+ were determined. In MC, sulphate levels were greater than nitrate levels, and NH4 had mixed sources (vehicular emissions and agriculture activities). MAM had markedly alkaline atmospheric deposition, Na + and Cl − levels were unexpectedly high, especially during hurricane "Alex". Low pH values were found in ECNP and nitrate concentrations were high, suggesting the influence of a local source (forest fires). Deposition fluxes (Kg•ha −1 •yr −1) for N-NO 3 , N-NH 4 and S-SO 4 were 1.36, 2.74 and 4.84 for MAM; 7.27, 0.57 and 4.32 for ECNP; and 5.97, 4.96 and 6.78 for MC, respectively. Nitrogen deposition fluxes in ECNP were high considering that this site is a natural reserve.

Study of Trace Ions in Wet Deposition of an Industrial Site in Monterrey’s Metropolitan Area, Mexico

“…High levels of calcium suggest a significant contribution from crustal sources; this was expected because calcisols are the dominant soil type in Monterrey Area [10] [24]. High levels of chloride and sodium were found during spring season (March-May) and during the norths season (October) when winds blew from ENE (from the Gulf of Mexico) bringing maritime air enriched with these ions.…”

Atmospheric N and S Deposition Fluxes in the Metropolitan Area of Monterrey, Mexico and Its Relation with Criteria Air Pollutants and Meteorological Conditions

“…However, since in the case of atmospheric deposition, it is not a criterion contaminant, that is, there is not a standard or reference value that regulates it, it is necessary to carry out monitoring studies at a medium or long term to establish a baseline that allows to perform an environmental diagnosis of the area and infer its possible effects. Notwithstanding, in the MAM, some authors [4][5][6][7] have measured wet and dry atmospheric deposition; these studies have been carried out at a short term and systematic measurements that allow a proper diagnosis considering the seasonal and spatial components are not available. Therefore, the present work focuses on the mapping and study of the seasonal and spatial variability of N and S atmospheric deposition in the metropolitan area of Monterrey (MAM), Nuevo Leon, during three climatic seasons (dry, rainy, and cold fronts) using passive samplers based on ionic exchange resin at ten points distributed throughout nine municipalities of MAM.…”