Characterization of gaseous and particulate phase polycyclic aromatic hydrocarbons emitted during pre-harvest burning of sugar cane in different regions of Kwa-Zulu Natal, South Africa.

Biomass burning is a significant anthropogenic source of air pollution, including the pre-harvest burning of sugar cane. These burn events result in atmospheric emissions, including semi-volatile organic compounds, that may have adverse impacts on air quality and human health on a local, regional and even a global scale. Gaseous and particulate polycyclic aromatic hydrocarbon (PAH) emissions from various sugar cane burn events in the province of Kwa-Zulu Natal in South Africa were simultaneously sampled using portable denuder sampling technology, consisting of a quartz fiber filter sandwiched between two polydimethylsiloxane multichannel traps. Total gas and particle phase PAH concentrations ranged from 0.05-9.85 µg m -3 per individual burn event where nine PAHs were quantified. Over 85% of all PAHs were found to exist in the gas phase with smaller two and three ring PAHs, primarily naphthalene, 1-methyl naphthalene and acenaphthylene, being the most dominant and causing the majority of variance between the burn sites. PAH profiles differed between the different burn events at different sites, emphasizing the significant influence that the crop variety, prevailing weather conditions as well as the geographical location has on the type and number of pollutants emitted. The potential carcinogenicity of the PAH exposure was estimated based toxic equivalency factors which showed varying risk potentials per burn event with the highest value of 5.97 ng m -3 . This article is protected by copyright. All rights reserved. Environ Toxicol Chem 2023;00:0-0. © 2023 SETAC.