Evaluating Inflammatory Responses of Naphthalene Secondary Organic Aerosol (SOA)

SEONGBIN JO, Liang-Hsin Chen, Shuichi Takayama, Nga Lee Ng, Georgia Institute of Technology

     Abstract Number: 421
     Working Group: Health-Related Aerosols

Abstract
Naphthalene is one of the polycyclic aromatic hydrocarbons (PAHs) that are commonly found in the environment. Naphthalene from anthropogenic emissions can react with atmospheric oxidants to form secondary organic aerosol (SOA). Naphthalene has been identified as a potent carcinogen and an immunotoxicant by activating aryl hydrocarbon receptors (AhRs). However, the immunotoxicity of SOA derived from naphthalene in a physiologically relevant model has not been studied owing to the complex chemical properties of SOA. Here, we conduct a series of laboratory experiments that involve formation of SOA from naphthalene and investigation of SOA toxicity using the air-blood barrier array (ABBA) module. The ABBA module mimics the human lungs epithelium and endothelium interface, allowing for examination of the cell-cell interactions in the lung barriers to fully investigate the inflammatory responses of naphthalene SOA exposure. First, we generate naphthalene SOA under different NOx conditions in photooxidation experiments. The chemical composition of the naphthalene SOA is characterized by high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and filter inlet for gas and aerosols time-of-flight chemical ionization mass spectrometer (FIGAERO-ToF-CIMS). Then, we use the ABBA module to investigate the naphthalene SOA-induced reactive oxygen species (ROS) and interleukin-8 (IL-8) production at the epithelium and the endothelium interface, which represent the initiation and mediation of inflammatory cascades from naphthalene exposure to the epithelial cells and subsequent responses in the endothelial cells. The measured inflammatory responses can demonstrate the series of immunotoxic responses leading to the degradation of lung barrier function.