AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
What Is the Toxicity of the Photooxidation Products of Atmospherically Relevant Volatile Organic Compounds?
HUANHUAN JIANG, Myoseon Jang, Sarah Robinson, Tara Sabo-Attwood, University of Florida
Abstract Number: 452 Working Group: Health Related Aerosols
Abstract Secondary organic aerosols (SOAs) comprise a major fraction of atmospheric organic aerosol and can influence the pulmonary system due to their small size in diameter. However, the pulmonary health effects of SOA are still relatively unknown. One of possible mechanisms of SOA toxicity is the reaction of SOA products with thiol groups in cell materials producing reactive oxygen species (ROS), which trigger inflammation in cells. In this study, various SOAs were produced via the photooxidation of four different VOCs [toluene, 1,3,5-trimethylbenzene (TMB), isoprene and alpha-pinene] in the presence of NO$_x using a large outdoor photochemical smog chamber (UF-APHOR). The resulting SOAs were efficiently collected using a Particle Into Liquid Sampler (PILS). In order to investigate oxidative potential in cells due to SOAs, dithiothreitol (DTT), a model thiol compound, was reacted with PILS samples and the depletion rate of DTT was observed. The depletion rate of DTT is proportional to the concentration of the catalytic redox-active species in the aerosol sample. Toluene SOA and isoprene SOA showed 2-7 times higher DTT response compared to TMB SOA or α-pinene SOA. Quinones in toluene SOA is believed to cause the depletion of DTT. However, the high DDT response in the isoprene SOA that contains no quinone, suggests that there is other mechanisms that can affect oxidative potential. Both toluene SOA and TMB SOA were applied to studies of biological responses using in vitro human airway epithelial cells (small air epithelial cells, SAEC). Toluene SOA also showed the higher inflammation response (IL-8) using in vitro SAEC than TMB SOA. The dose-response relationship between inflammation response and dose-mass of SOA will be measured. The mechanism behind the toxicity of SOA will also be further investigated in the future.