Abstract View
Concentrations of Atmospheric VOCs Emitted from Fireworks in Southwest Mexico City Measured by a Real-time Vocus PTR-TOF-MS
MARGARITA PALACIOS-ARREOLA, Maribel Hernández-Camarillo, Jessica Ortiz-Gutiérrez, Pawel K. Misztal, Omar Amador-Muñoz, Universidad Nacional Autónoma de México
Abstract Number: 657
Working Group: Urban Aerosols
Abstract
Fireworks and bonfires are intensively used in New Year celebrations and various cultural and religious festivals, producing pollution plumes concentrated over short spatiotemporal scales. It is currently unknown what impact these sources have on air quality and health.
A Vocus proton transfer reaction time of flight mass spectrometer (Vocus PTR-TOF-MS) is a novel analytical technique allowing for continuous real-time measurements of volatile organic compounds (VOCs) with an ultralow detection limit (sub-ppt). Outdoor ambient air measurements were carried out at the southwest region of Mexico City, from December 7th to 14th, 2020 using a high resolution Vocus 2R PTR-TOF-MS (Tofwerk, Switzerland) operated in a positive ionization mode with H3O+ as a primary ion.
During December 12th festival (in celebrations of the Virgin of Guadalupe Day), intensive fireworks and bonfires were associated with large enhancements of numerous hydrocarbons and oxygenated VOCs. Aromatics were among the prominent compounds. Benzene reached 1,500 times higher concentration during the times of fireworks, than in the other days. Toluene and C10 aromatics rose up to 300- and 250-times higher baseline concentration, respectively. Those compounds are associated with industrial and vehicle emissions. Regarding oxygenated VOCs, the most enhanced compound was acetic acid, which increased approx. 200 times, while butanal/butanone exhibited an 80 times higher than typical concentration. In contrast, monoterpenes and sesquiterpenes retained a typical circadian behavior during the week, with a moderate spike, possibly associated to pine wood burning in bonfires, commonly burnt during this event. This is supported by the finding of increases in biomass burning tracers, such as furfural (10 times higher) and acetonitrile (3 times higher).
The VOC enhancements seem attributable to the festival based on an agreement between the time of the event, observed VOCs and also the higher concentrations of both PM10 and PM2.5 measured at the air quality monitoring station nearest to the event location.
This work aims to contribute with chemical fingerprinting of firework and bonfire plumes and discusses potential impacts of these episodic sources on urban air quality.
Authors acknowledge the financial support to CONACyT-Infrastructure 300618.