Toxicity of Complex Aerosols emitted from Woody Biomass Combustion assessed using a novel In Vitro technology

Abstract:

Wildfire emissions consist of particulate matter (PM), various volatile organic compounds, and other gases that are harmful to human health. Epidemiological and toxicological studies, however, have focused separately on the adverse health effects of exposures either to gas-phase pollutants or PM. Much less is known about the combined effects of PM and gases and their interaction with other pollutants. In addition, most studies use freshly generated particles that have not been photochemically aged. Because the components of PM constantly change due to photochemically-mediated transformations, the overall toxicity of the mixture is also likely to change. Due to the difficulty in producing these types of mixtures, the toxicity of dynamic and complex gas/PM exposures is currently understudied. We hypothesize that fresh and photochemically aged biomass emissions have different biological impacts. Through this work we have generated and chemically characterized fresh and photochemically aged emissions from a hardwood source in an indoor smog chamber and generated real time in vitro exposures of lung epithelial cells to emitted gas/PM mixtures at an air-liquid interface (ALI). This was accomplished using the CelTox Sampler; a novel instrument providing a more sensitive and realistic ALI in vitro exposure that enables studying biological and chemical impacts without the artifacts associated with conventional resuspension methods. The exposed cells were then analyzed for gene expression changes and cytotoxicity levels in an effort to correlate biological data with chemical characterization data. These analyses will provide new insights on the scientific drivers of the health impacts of exposure allowing for improved monitoring, modeling, and forecasting.