Autores: Andrea Patricia Cuesta-Mosquera, MatthewWahl, Jansen GabrielAcosta-López, José Agustín García-Reynoso*, Beatriz Helena Aristizábal-Zuluaga

* Ciencias Ambientales | Fisicoquímica de la Atmósfera

Abstract

istinct times of sulfur dioxide concentration (SO₂) were observed in the main square of a tropical Andean city, revealing strong meteorological control of SO₂. Concentrations were measured by UV fluorescence at 5-minute intervals, and compared to local meteorological forcing. A consistent morning peak of SO₂ (4.32 μg∙m⁻³ at 7:40 AM) was concurrent with peak traffic, and occurred 10 minutes into an 80-minute period of calm (wind velocities ˂ 0.3 m s⁻1). Instead of accumulating, SO₂ decreased 54%, due an expanding mixing layer. Peak evening SO₂ (5.2 μg∙m⁻³ at 8:15 PM) was observed 2:15 hours after flow reversal, and consistent with travel-times of an air parcel descending from industrial facilities. The consistent anthropogenic emissions formed a pattern of daily SO₂ concentration that aided in identifying more random volcanic SO₂. Manizales (pop. 400000) is located on the western slope of the Cordillera Central in proximity to the Nevado del Ruiz volcano. The complex trajectory necessary for volcanic SO₂ to arrive in the main square was simulated for the highest observed concentration (114 μg•m⁻³), using Hysplit and Aura-OMI information. This type of analysis can be applied to urban planning – from locating industrial zones to managing transportation – particularly in tropical montane cities.