AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Isoprene-derived Secondary Organic Aerosol and Epoxide Intermediates Induce Altered Expression of Inflammation-associated Genes in Lung Cells
YING-HSUAN LIN, Maiko Arashiro, Zhenfa Zhang, Avram Gold, Ilona Jaspers, Rebecca Fry, Jason Surratt, University of North Carolina at Chapel Hill
Abstract Number: 55 Working Group: Linking Aerosols with Public Health in a Changing World
Abstract Secondary organic aerosol (SOA) derived from OH-initiated oxidation of isoprene (2-methyl-1,3-butadiene) has been recognized as a substantial source contributing to the total ambient PM2.5 mass in isoprene-rich environments. Whether SOA derived from this source contribute to adverse health effects induced by exposure to ambient PM2.5 is unknown. To evaluate the toxicological potency of isoprene-derived epoxide intermediates and the resultant SOA constituents, cytotoxicity and proinflammatory cellular responses were examined using an in vitro model of human airway epithelial cells (BEAS-2B). Here, the release of lactate dehydrogenase (LDH), XTT-based cell proliferation assays, and inflammation-associated gene expression were assessed to study potential biological effects on lung cells. Isoprene-derived epoxides, including isoprene epoxydiols (IEPOX) and methacrylic acid epoxide (MAE), were synthesized, and the SOA constituents were generated from heterogeneous reactive uptake of IEPOX and MAE onto preexisting sulfate seed aerosols in a series of controlled smog chamber experiments under conditions simulating urban and downwind urban atmospheres impacted by isoprene emissions. SOA constituents were collected on Teflon membrane filters and extracted for subsequent cell exposure. Aliquots of the filter extracts were chemically characterized at the molecular level and quantified using ultra performance liquid chromatography interfaced to quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-Q-TOFMS) equipped with electrospray ionization (ESI), and electron impact gas chromatography-mass spectrometry (GC/EI-MS) following trimethylsilyl derivatization. Associations between identified SOA chemical compositions and biological/toxicological effects will be presented to discuss potential health risk induced by isoprene-derived SOA exposure.