Ionic species associated with PM2.5 in the City of Guadalajara, México during 2007

Abstract

Atmospheric aerosol particles were collected from January to December 2007 at two sites in the City of Guadalajara. The first site (Centro) is located in the downtown, which is characterized by high vehicular traffic, and the second site (Miravalle) is in the southern part of the city, characterized by emissions from high industrial and vehicular activity. Sulfates, nitrates, and ammonium were the most abundant ions at both sites. Similar concentrations of sulfates, nitrates, and ammonium were observed throughout the year at Centro while only sulfates and nitrates were similar at Miravalle. From the balance of anions and cations at the two sites, Centro was determined to have acidic particles, while at Miravalle, the particles were alkaline. Based on the analysis of the ammonium/sulfate molar ratios, it was determined that in Centro, there was not enough ammonium to neutralize the sulfate, while at Miravalle, ammonium practically neutralized all sulfate.

Potential Sources of Trace Metals and Ionic Species in PM2.5 in Guadalajara, Mexico: A Case Study during Dry Season

“…Thus, those atmospheric particles had acidic properties during this sampling period. These results are consistent with those previously reported [28] for the Centro site in 2007, taking into account the same ionic species, while in Miravalle a slope of about 1.0 (1.08) was obtained, indicating neutralization processes, which is different than that observed during a previous study [28]. Thus, there were enough cations to neutralize the sulfate and nitrate present in the Miravalle environment, which likely originated either by contribution of additional cations from resuspended particles (Ca 2+ , Mg 2+ ) or from being buffered by the higher average concentrations of NH 4 + found in Miravalle [58], which were almost two-fold of that measured in Centro (Table 4).…”

“…The environmental levels of inorganic species are of the same order of magnitude as those already reported in an earlier study [28]. The statistical analysis, via the Mann-Whitney U test, showed that the higher median concentration of NO 3´w as in Miravalle.…”

“…The details of the samples' chemical analysis are described in Saldarriaga et al [27] and Hernández et al [28]. Briefly, for the analysis of metals, the PTFE filters were extracted in an ultrasonic bath for 3 h at about 60˝C-70˝C, using 50 mL of HNO 3 -HCl (2.6:0.9 M).…”

“…In addition, this can contribute to a better understanding of their formation mechanism in urban areas. So far, the earliest studies undertaken to identify sources suggest that PM 2.5 in Guadalajara results from a mixture of anthropogenic and biogenic sources [25][26][27][28]. However, analysis of information on how particles are specifically emitted and how they respond to variations in their environment during the warm dry season is scarce.…”

Modelado De Partículas Pm10 Y PM2.5 Mediante Redes Neuronales Artificiales Sobre Clima Tropical De San Francisco De Campeche, México

“…Tales son los casos de zonas metropolitanas como el Valle de México, Guadalajara y Monterrey. [11][12][13][14] Sin embargo, en la mayoría de las zonas provinciales de la República Mexicana, existe poca información al respecto, tal es el caso de la Ciudad de San Francisco de Campeche, capital del Estado de Campeche, la cual presenta un clima tropical húmedo 15 convirtiéndola en una locación idónea para la realización de estudios de evaluación temprana de calidad del aire. Así mismo, la ciudad es considera Patrimonio Cultural de la Humanidad por la UNESCO desde 1999, por lo que se pretende realizar un estudio sobre contaminantes atmosféricos y su relación con variables meteorológicas en la ciudad y evaluar los efectos de los aerosoles atmosféricos sobre la población y materiales de interés histórico-artístico.…”