Recognition of the importance of geogenic sources in the content of metals in PM2.5 collected in the Mexico City Metropolitan Area

Abstract

The study of airborne metals in urban areas is relevant due to their toxic effects on human health and organisms. In this study, we analyzed metals including rare earth elements (REE) in particles smaller than 2.5 μm (PM), collected at five sites around the Mexico City Metropolitan Area (MCMA), during three periods in 2011: April (dry-warm season, DW), August (rainy season, R), and November (dry-cold season, DC). Principal component analysis allowed identifying factors related to geogenic sources and factors related to anthropogenic sources. The recognition of the high impact of geogenic sources in PM is in agreement with the REE distribution patterns, which show similar behavior as those shown by igneous rocks, confirming the influence of the regional geogenic material. Metals associated to geogenic sources showed higher concentration (p < 0.05) at NE of the MCMA and a significant correlation with prevalent winds. Geogenic metals show similar seasonal distribution, with the highest concentration during DW (p < 0.05), suggesting a possible metal resuspension effect which affects more significantly at lower relative humidity (RH). The metals associated with anthropogenic sources are in agreement with the urban complexity of the area, showing homogenous distribution throughout MCMA (p > 0.05) and no similar seasonal pattern among them. These unexpected results exposed outstanding information regarding the identification of different geogenic sources as the main contributors of metals in the atmospheric environment in the MCMA and highlighted the importance of meteorology in the spatial and seasonal metal patterns.

PM2.5 Characterization and Source Apportionment Using Positive Matrix Factorization at San Luis Potosi City, Mexico, during the Years 2017–2018

“…Source 4 is considered as vehicular emission-related, containing S, Ni, [46] traced by OC, EC [48,54] and a contribution of other elements (Na, K, Cl, Fe, Cr, and Pb) produced not just by combustion, but also by tires and brakes [22,45,49,[55][56][57]. Also, this source can contain diesel or a fuel combustion mixture due to a nearby car racing circuit in "Parque Tangamanga" and a bus station at the zone.…”

The wild plant Gnaphalium lavandulifolium as a sentinel for biomonitoring the effects of environmental heavy metals in the metropolitan area of México Valley

“…The MAMV has a high population density, industrial zones, and a great vehicle fleet. According to the Automatic Atmospheric Monitoring Network, daily have recorded several heavy metals (HM), particulate matter, gases (Morton-Bermea et al, 2018), and polycyclic aromatic hydrocarbons (Villalobos-Pietrini et al, 2007;Amador-Muñoz et al, 2011. The frequent thermal inversions in this Valley surrounded by mountains cause a temporary stagnation of air masses in the atmosphere, inhibiting dispersion and favoring the accumulation of pollutants (Amador-Muñoz et al, 2011;SEMARNAT, 2015).…”