Identifying The Ozone Weekend Effect In The Air Quality Of The Northern Andean Region Of Ecuador
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169 - 180
R. Parra, E. Franco
The Weekend Effect (WE) is a phenomenon that occurs in some urban areas, characterized by increased concentrations of O3 and decreased emissions of its precursors (NOx and VOC) during weekend days, in comparison to weekdays. The study of the WE is relevant for understanding the behavior of pollutants; and hence, for air quality control. We analyzed the hourly records of the period 2005–2012, from 8 stations of the air quality network from the Distrito Metropolitano de Quito (northern Andean region of Ecuador). Both for each station and year, 3 mean-daily profiles were obtained for CO, NO2, PM2.5 and O3, corresponding to weekdays, Saturdays and Sundays. The CO, NO2 and PM2.5 profiles from Centro (historic center of Quito) and Belisario (center-north) stations, declined on Sundays. However the O3 profiles were higher on Saturdays and Sundays. The O3 8-h mean concentrations of Sundays were higher in Belisario (19.7–31.1%) and Centro (11.7–18.4%), in comparison to weekdays. These results indicate the presence of the WE around these 2 stations, which probably are located in a VOC-limited region for photochemical O3 production.
Distrito Metropolitano de Quito, VOC-Limited Regime, NOx-Limited Regime