Toxicological Impact of Secondary Organic Aerosol Compounds in Air-Liquid-Interface Exposed Lung Cell Models

Svenja Offer, Elena Hartner, Thomas Gröger, Yinon Rudich, Michal Prado, Astrid Kiendler-Scharr, Thorsten Hohaus, Andreas Paul, Sebastiano di Bucchianico, Martin Sklorz, Hendryk Czech, RALF ZIMMERMANN, Helmholtz Zentrum München and University of Rostock

     Abstract Number: 250
     Working Group: Aerosol Exposure

Abstract
In the framework of the aeroHEALTH Helmholtz International Lab, the impact of atmospheric aging on health effects is elucidated. We investigated differences in toxicological effects of Secondary Organic Aerosols (SOA) generated by photochemically aging of a biogenic (β-pinene) or an anthropogenic (naphthalene) organic precursor with combustion-derived soot particles (SP) as seed in two different lung cell models exposed at the air-liquid interface (ALI). Lung epithelial cell monocultures (A549) and a co-culture model (A549 and EA.hy926-endothelial cells) were exposed at the ALI for 4 h to different aerosol concentrations of pure SP (CAST), β-pinene-SOA on SP (SOA_βPIN-SP) or naphthalene-SOA (SOA_NAP-SP) on SP. The aerosols were comprehensively characterized (physical/chemical properties) and toxicity tests were conducted to determine cytotoxicity, intracellular oxidative stress, genotoxicity, inflammatory effects etc. in the models (Offer et al, EHP 2022). Both investigated SOA-types caused significant toxicological effects. The toxicological assays furthermore indicated greater adverse effects of SOA_NAP-SP compared with SOA_βPIN-SP in both cell models. At functional level SOA_NAP-SP augments the secretion of e.g. malondialdehyde and interleukin-8, inducing an activation of endothelial cells (co-culture), confirmed e.g. by comet assay suggesting secondary genotoxicity. Chemical characterization of PM revealed distinct differences in the composition of the two secondary aerosol types. It is shown that SOA-compounds can increase the toxicity of primary SP, which are ubiquitous in inhabited and wildfire influenced areas. Aromatic precursors, such as naphthalene caused the formation more oxidized, more aromatic SOA of higher oxidation potential with higher toxicity compared to an aliphatic precursors, such as β-pinene. The influence of atmospheric chemistry on the chemical PM composition play a crucial role for the adverse health-outcomes of emissions. Further comparable experiments have been conducted with CAST soot aerosols (ultrafine particles) with different chemical composition (high/low content of polycyclic aromatic hydrocarbons) and with real emissions (e.g. fresh and photochemical aged car emissions).