AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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Implications of Photochemical Ageing for Toxicity and Source Apportionment of Wood Combustion Aerosols: A Combined Biological and Chemical Study
Hendryk Czech, Toni Miersch, Anni Hartikainen, Mika Ihalainen, Sebastiano di Bucchianico, Jürgen Orasche, Sebastian Oeder, Jarkko Tissari, Thorsten Streibel, Jürgen Schnelle-Kreis, Pasi Javala, Maija-Riitta Hirvonen, Olli Sippula, Jorma Jokiniemi, RALF ZIMMERMANN, HICE Consortium, University of Rostock and Helmholtz Zentrum Munich, Germany
Abstract Number: 535 Working Group: Biomass Combustion: Emissions, Chemistry, Air Quality, Climate, and Human Health
Abstract Wood combustion in residential stoves is a substantial contributor to air pollution and releases high levels of particle-bound polycyclic aromatic hydrocarbons (PAH) and oxygenated PAH (OPAH). In the atmosphere those compounds undergo chemical transformation along with SOA formation from gaseous compounds, which is changing the toxicity of the wood combustion emissions. In this study, we aged spruce-logwood combustion-aerosol by a recently described high-flow oxidation flow-tube reactor (Ihalainen et al., AS&T, 2019) and investigated the effect of ageing on PAH and OPAH emissions, PAH diagnostic ratios for emission source identification and the carcinogenicity (based on PAH toxicity equivalent approach (PAH-TEQ). The cytotoxicity and genotoxicity of primary and aged emissions were assessed in 4 h in vitro air-liquid-interface (ALI) exposures of human lung cell lines (A549, BEAS2B). Furthermore, transcriptome and proteome analysis of the exposed cells and controls were performed (multi-omics approach, Oeder et al., PLoS one, 2015). The combustion of spruce logwood released 404µg/330µg MJ-1 of analysed OPAH, most of which are known or potential mutagens/carcinogens. Photochemical flow-tube processing substantially degraded particle-bound PAH (PAH-TEQ declines by 45-80% per equivalent day of photochemical-ageing). Compared to PAH, OPAH were less affected, while hydroxylated-PAH increased by secondary formation. Genotoxicity is increased significantly from clean air control to both, primary and aged aerosol (comet assay), but without quantitative differences between primary and aged spruce aerosol, despite the drastically reduced genotoxic PAH-concentrations. This study also showed an increased cytotoxicity of wood combustion emission by photochemical atmospheric transformation. The in-depth transcriptome analysis revealed different genotoxic mechanisms and induced DNA damage. Some diagnostic PAH ratios to identify wood combustion emissions in ambient air remain stable during photochemical ageing while other ratios allow monitoring of the photochemical age.