Wet Deposition Fluxes and Related Atmospheric Chemistry at Three Sites in Mexico (original) (raw)
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Spatiotemporal Variations in Chemical Composition of Wet Atmospheric Deposition in Mexico City
Aerosol and Air Quality Research
A comprehensive analysis of the chemical composition of wet atmospheric deposition was performed on 7048 samples collected between 2003 and 2021 over Mexico City. The descending ion abundance trend was NH4 + > SO4 2-> NO3-> Ca 2+ > Cl-> H + > Mg 2+ > Na + 18 > K + , probably associated with industrial activity, heavy traffic and agricultural activities. Although main precursors have decreased importantly, ion composition did not show a clear trend throughout the years. Maximum concentrations of major ions were found in the northern and central part of the megacity, due to the impact of the Tula industrial corridor
Air Pollution: monitoring, quantification and removal of gases and particles [Working Title]
The objective of this study was to assess the spatial and temporal variability of N and S atmospheric deposition and its relation with criteria air pollutants (CAPs) and meteorological conditions (MCs) in the metropolitan area of Monterrey (MAM). Atmospheric deposition was collected in 10 sampling sites during 3 climatic periods by using passive samplers based on ionic exchange resins (IERs); simultaneously, CAP and MC were monitored. Ions were extracted from IER to determine nitrate, ammonium, and sulfate levels, and deposition fluxes were estimated. On the other hand, from CAP and MC, wind and concentration roses were built to identify the exceedances of the current regulations, and relationships between CAP and meteorological conditions. It was found that only S deposition fluxes exceeded critical load values proposed in Europe, suggesting that S deposition could be a serious threat in MAM. It was found that CO in Juárez sampling site and O 3 and PM 10 in all sampling sites showed exceedances of the current regulatory limits, showing seasonal and spatial patterns similar to N and S deposition fluxes. Deposition fluxes were mapped to identify critical zones or periods in which these fluxes could be higher as a result of the prevailing meteorological conditions.
Chemical composition of rainwater collected at a southwest site of Mexico City, Mexico
Atmospheric Research, 2007
Measurements of the trace metals Cd, Cr, Mn, Ni, Pb, V and Al in soluble and insoluble rain fractions and SO 4 − 2 , NO 3 − , Cl − , HCO 3 − , Ca 2+ , Mg 2+ , Na + , K + , NH 4 + and H + in soluble fractions were performed in rainwater collected at a southwest site of Mexico City during the rainy seasons of 2001 and 2002. Aluminum presented the highest volume-weighted mean concentration (VWMC) in both insoluble and soluble fractions. In the insoluble fractions, the VWM of the other trace metals decreased in the order Mn, Pb, Ni, V, Cr and Cd, and in the soluble fractions in the order Mn, V, Ni, Pb, Cd and Cr. Ammonium presented the higher VWMC, followed by SO 4 2− , NO 3 − , HCO 3 − , Ca 2+ , Cl − , H + , Na + , Mg 2+ and K + . Air mass back trajectories were associated to the concentrations of trace metals and of SO 4 2− , Ca 2+ , Mg 2+ , NH 4 + and H + observed during each rainy day. Trace metal concentrations were not clearly related to wind direction. Enrichment factors related to the relative abundance of elements in crustal material were calculated using Mg as reference. The high enrichment factors (EF c ) suggested that, in general, trace metals and major ions had an anthropogenic origin. Aluminum, K + , and Ca 2+ were the only elements that had a significant crustal source. Factor analysis (Principal Component Analysis) with Varimax normalized rotation grouping the elements analyzed into three factors. Factor 1 indicated a crustal contribution for Ca 2+ , K + , Mg 2+ and anthropogenic sources for SO 4 2− , NH 4 + and V. Factor 2 indicated a high loading for Al, Ni and Mn, that indicate possible contribution of anthropogenic sources but with a significant crustal contribution for Al. Factor 3 indicated an anthropogenic origin for H + and NO 3 − . Pearson's correlations show that Al correlated with all the metals, including Ca 2+ and Mg 2+ .
Atmosfera, 2021
Bulk deposition was studied along an urbanization gradient in the state of Nuevo Leon, Mexico. During a yearlong period seven sites within the Metropolitan Area of Monterrey (MAM) and two rural sites (Allende and Linares) were monitored, with the purpose of characterizing deposition and identifying possible patterns between sites. A total of 32 rainfall events were collected. An average pH of 7.15 ± 0.02 was found, which indicates the presence of neutralizing substances in rainwater, as well as an average Electrical Conductivity of 153.96 ± 6.83 μS/cm. The annual accumulated deposition follows the descending order Ca> K> Mg> Zn> Fe> Mn> Cu> Cd> Ni and does not show significant differences between urban and rural areas, with the exception of Ca (p = 0.017). The Principal Component Analysis shows that metals (Cu, Zn, Ni, Mn, and Cd) represent an important pathway in the deposition phenomena and this behavior is maintained through the urbanization gradient, whic...
Wet and dry deposition of trace elements in two sites in Carmen Island, Campeche, Mexico
Wet and dry deposition samples were collected in two sampling sites (urban and mangrove forest) in Carmen Island, Campeche, Mexico from February to November, 2013. Samples were collected with an automatic wet/dry deposition sampler, using a device called DAS (Dry deposition on aqueous surfaces) that uses water as collection surface in the case of dry deposition. Wet deposition samples were collected daily, whereas dry deposition was collected on a weekly basis. In both cases, samples were analyzed for pH, conductivity, Na + , K + , Ca 2+ , Mg 2+ , NH 4 + , NO 3-, SO 4 2-and Cl −. Calcium and nitrate were the most abundant ions, contributing in a great proportion to the total ionic mass. In both sampling sites, it was completely evident the influence of local sources, and in the case of the urban site, a local source (building activities) contributed to extremely high values of calcium. N deposition fluxes in both sampling sites exceeded the critical loads and the hemispheric background concentrations proposed for sensitive ecosystems and marine remote sites. Nitrogen total deposition at Carmen Island is already above of the upper extreme of the threshold value reported for sensitive ecosystems. Since only local sources drove the chemistry of the total deposition in both sampling sites, sulfate levels remained below of the background hemispheric values, suggesting that the contribution of regional sources of this ion was not significant. However, it is necessary to take local regulatory measures to avoid that total N deposition be a threat for the ecosystems in Carmen Island.
Agrociencia, 2018
espanolEl deposito atmosferico de sustancias acidificantes altera - doras del equilibrio de los sistemas montanosos tropicales altamente sensibles al deposito de compuestos de N y S se ha estudiado poco en Mexico. El objetivo del estudio fue evaluar la distribucion espacial y temporal del deposito de N y S, durante un ano, en el Valle de Orizaba, y estimar el efecto del transporte a gran escala de emisiones regionales de SO 2 sobre el deposito atmosferico de S en la region. La hipotesis fue que los depositos de N y S en el Valle de Orizaba provienen de fuentes locales y regionales, respectivamente. Los depositos de N y S se midieron en recolectores pasivos con resinas de intercambio ionico (RII) en 10 sitios, a lo largo del Valle de Orizaba, Veracruz, Mexico, en 2015. Los iones retenidos ( NO 3 , NH 4 y SO 4 2 ) en la columna RII se extrajeron con KCl 2 N y analizaron por el metodo colori - metrico del indofenol azul y turbidimetria. Las cantidades medias anuales de N y S depo...
Química de la precipitación pluvial en dos bosques de la cuenca de la Ciudad de México
Agrociencia, 2006
En este estudio se analizó la alteración química del agua de lluvia en dos bosques templados con alto (Desierto de los Leones; DL) y bajo depósito de contaminantes atmosféricos (Zoquiapan; ZQ) en la cuenca de la Ciudad de México. Durante la temporada de lluvia (agosto-octubre, 2003) se midió la concentración de los principales iones de origen antropogénico ( SO 4 2− , NO 3 − , NH 4 + y H + ) en la precipitación pluvial, su variabilidad y la influencia de la cantidad de lluvia en la concentración iónica. Para ello se recolectó el depósito atmosférico total semanalmente, colocando recolectores en claros del bosque. La precipitación pluvial total recolectada fue 758 mm en DL y 329 mm en ZQ. La concentración iónica del agua de lluvia también fue mayor en DL con 43.3, 33.2 y 49.0 μeq L −1 de SO 4 2− , NO 3 − y NH 4 + , mientras en ZQ las concentraciones fueron 28.8, 16.3 y 34.6 μeq L −1 . También se encontró una correlación negativa significativa (p≤0.0001) entre el volumen total de lluvia y la concentración iónica. Lo anterior evidencia la influencia de la contaminación atmosférica de la zona metropolitana de la ciudad de México en los ecosistemas forestales del DL y en la calidad del agua captada. Palabras clave: Contaminación atmosférica, depósito ácido, depósito húmedo, ecosistemas forestales. ABSTRACT In this study chemical changes in rainfall water were evaluated in two temperate forests: (Desierto de los Leones: DL; high atmospheric deposition) and (Zoquiapan: ZQ; low deposition) in the basin of México City. During the rainy season (August-October, 2003), concentrations of the major ions of anthropogenic origin ( SO 4 2− , NO 3 − , NH 4 + and H + ) in rainfall, its variability and the effect of precipitation quantity on ionic concentrations were studied. Total atmospheric deposition were collected on a weekly basis by placing rainfall collectors in forest clearings. At DL the total amount of rain collected was 758 mm and 329 mm at ZQ. Ionic concentrations in rain water were also greater at DL, with 43.3, 33.2 and 49 μeq L −1 of SO 4 2− , NO 3 − and NH 4 + , respectively, compared to 28.8, 16.3 y 34.6 μeq L −1 at ZQ. A significant negative correlation (p≤0.0001) was also found between total rain volume and ionic concentration. These findings provide evidence of the influence of atmospheric pollution from the metropolitan zone of México City on forest ecosystems at DL and on water quality from these forested watersheds.
Acidic Gases and Nitrate and Sulfate Particles in the Atmosphere in the City of Guadalajara, México
Bulletin of Environmental Contamination and Toxicology, 2012
Atmospheric concentrations of nitrous acid, nitric acid, nitrate and sulfate particles were obtained in this study from April to June 2008 in the center of the city of Guadalajara, while concentrations of ozone, sulfur dioxide, nitrogen dioxide and meteorological parameters (temperature and relative humidity), were acquired by the Secretaría del Medio Ambiente para el Desarrollo Sustentable del Estado de Jalisco (SEMADES). The results showed that nitric acid (2.7 lg m-3) was 2.7 times higher than nitrous acid (1.0 lg m-3). The sulfur dioxide (SO 2) concentration indicated an opposite trend to sulfate (SO 4 2-), with the average concentration of SO 2 (6.9 lg m-3) higher in almost the entire period of study. The sulfur conversion ratio (Fs, 24.9%) and nitrogen conversion ratio (Fn, 6.2%), were revealed to be similar to that reported in other urban areas during warm seasons. It is also noted that ozone is not the main oxidizer of nitrogen dioxide and sulfur dioxide. This determination was made by taking into account the slightly positively correlation determined for Fn (r 2 = 0.084) and Fs (r 2 = 0.092) with ozone that perhaps suggests there are other oxidizing species such as the radical OH, which are playing an important role in the processes of atmospheric oxidation in this area.
Journal of Environmental Protection, 2013
Two hundred and seven rain events from April to October 2012 were collected in Carmen Island, Campeche, Mexico, and the concentration of 8 major ions with the pH of the rainwater was analyzed. Chemical composition variations as a result of seasonal patterns, meteorological conditions, and mixed local and regional sources contribution were assessed. In spite of the fact that nitrate and sulfate levels were higher than background hemispheric values, the average pH values were almost neutral. Carmen Island was under the influence of both, local and long-range transported emissions. Chemical composition showed a dilution effect as a result of the monthly rainfall amount. Ca 2+ and Na + were the most abundant ions, and these ions acted as acid neutralizers and buffered the acidity of the rain, suggesting that marine and crustal aerosols played an important role in the acid-base interactions. Wet deposition fluxes obtained were compared with reference values proposed as critical loads, fluxes obtained in this study did not exceed the critical values reported for sensitive ecosystems in Europe, indicating that this site has yet enough capacity to support acidity, nitrogen and sulfur deposition. However, it is necessary to obtain reference values characteristics for tropical regions.
WSEAS Transactions on Environment and Development
In this study, throughfall deposition of N and S was measured in two regions at the center and at the southeast of Mexico. In the region 1, sampling was carried out from June 6, 2014 to January 6, 2015 at Xicalango-Atasta region. In the region 2, throughfall deposition was collected from November 29, 2014 to February 7, 2015 at Córdoba-Orizaba region. Passive throughfall collectors were used to collect samples in 23 sampling points distributed along these two regions in a multiple transects design. Ions retained (NO3- , NH4+, and SO4=) by the resin column were extracted with 2N KCl, and analyzed by colorimetry and turbidimetry. Mean throughfall deposition fluxes for N (NO3- + NH4+) and S (SO4=) were 0.8 and 9.22 Kg /(ha* yr), respectively in region 1. N deposition flux in Xicalango-Atasta region did not exceed the critical load proposed; however, throughfall deposition flux for S was 3 times higher than those proposed for sensitive areas, suggesting that S deposition could be a thre...