WSEAS Transactions on Systems
Print ISSN: 1109-2777, E-ISSN: 2224-2678
Volume 12, 2013
Measurements of Atmospheric Pollutants (Aromatic Hydrocarbons, O3, NOx, NO, NO2, CO, and SO2) in Ambient Air of a Site Located at the Northeast of Mexico during Summer 2011
Authors: , , , , ,
Abstract: Volatile organic compounds (aromatic hydrocarbons: benzene, ethyl benzene and p-xylene), O3, NO2, NO, NOX, CO, SO2 and meteorological parameters were measured in ambient air of a site located in the Metropolitan Area of Monterrey, Mexico. A total of 69 samples were collected for aromatic hydrocarbons and analyzed by Gas Chromatography with Flame Ionization Detection (GC-FID). Criteria pollutants concentrations were determined by automatic analyzers and meterological parameters were measured by a portable meteorological station. A marked diurnal variation was found for the three measured aromatic hydrocarbons. The highest concentrations occured during the morning sampling period (from 09:00 to 10:30 h) followed by the midday sampling period (from 12:00 to 13:30 h) and showing the lowest concentrations during the afternoon sampling period (from 15:00 to 16:30 h). Mean concentrations for benzene, ethyl benzene and pxylene were: 0.9, 1.06 and 1.63 μg m-3, respectively. Aromatic hydrocarbons abundance showed the following order: p-xylene > ethyl benzene > benzene. All criteria pollutants showed concentration values lower than the maximum permissible values requested by the air quality Mexican standards, only ozone showed levels approaching to the standard value. A relation among criteria pollutants, meteorological parameters and aromatic hydrocarbons was found using a Principal Compound Analysis (PCA), identifying some associations among the pollutants originated in common sources. Air pollutants maximum concentrations were found when winds blowed from NE. Important industrial sources and avenues with high vehicular traffic are located in this direction. These sources could contribute to the levels measured in the studied site. This site did not show a clear pattern of VOC’s/NOX sensitiviness to ozone formation during the study period.
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Keywords: Volatile organic compounds, Aromatic hydrocarbons, Air pollutants, Monterrey, Mexico, Principal Compound Analysis, Ozone