TITLE:
Ionic Composition in Aqueous Extracts from PM2.5 in Ambient Air at the City of Cuernavaca, México
AUTHORS:
Hugo Saldarriaga-Noreña, Leonel Hernández-Mena, Enrique Sánchez-Salinas, Fernando Ramos-Quintana, Laura Ortíz-Hernández, Rodrigo Morales-Cueto, Vanesa Alarcón-González, Sandra Ramírez-Jiménez
KEYWORDS:
Ionic species, Cuernavaca, Ion Balance
JOURNAL NAME:
Journal of Environmental Protection,
Vol.5 No.13,
October
28,
2014
ABSTRACT: The present study was carried out between May and June 2012 in the city
of Cuernavaca, Mexico. During this time the average ambient temperatures were
about 25°C, suggesting the formation of secondary aerosols, consisting mainly
of ammonium and sulfate. The average PM2.5 concentration was 37 μg·m-3 for the entire
urban area and there were only two days which exceeded the limit established by
the official standards for periods of 24 h. The most abundant ionic species
associated with PM2.5 were sulfates (3634.82 ng·m-3, average) and
ammonium (1709.53 ng·m-3, average). The ratio estimated between total anions and
total cations indicated that the concentration of total anions was 1.94 times
total cations. The contribution percentage of the ionic species associated with
PM2.5 revealed that 76% of the PM2.5 is sulfates and ammonium. The ion balance
made for the urban area of Cuernavaca indicated that during the study
period, the aerosols showed alkaline characteristics; that is to say the
concentration of anions was not sufficient to neutralize the cations,
specifically ammonia (m = 0.060). Finally, wind fields showed that during the
study the winds came in 50% from the south west, followed by 25% from east and
12.5% of the south east, which in part allowed transport of contaminants into
the portion of the city, where the AUSM campus site was located.