Identifying the Ozone Weekend Effect in the air quality of the northern Andean region of Ecuador

Researchers identified the Ozone Weekend Effect (WE) in Quito, Ecuador, where ozone (O₃) levels peak on weekends while emissions of its precursors (NOₓ and VOCs) decline. Analyzing hourly air quality data from 2005 to 2012 at two urban stations—Centro (historic center) and Belisario (center-north)—the study found that Sunday O₃ concentrations were significantly higher, by 19.7–31.1% in Belisario and 11.7–18.4% in Centro, compared to weekdays. This suggests Quito operates under VOC-limited conditions for photochemical O₃ production, a critical insight for air quality management in the northern Andean region.

Parra, R., & Franco, E. (2016). Identifying the Ozone Weekend Effect in the air quality of the northern Andean region of Ecuador. Air Pollution XXIV, 1, 169–180. https://doi.org/10.2495/air160161