AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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Oxidative Potential and Cytotoxicity of Ambient Fine Particulate Matter During Winter at Beijing, China and Gwangju, Korea
Ma. Cristine Faye Denna, Lucille Joanna Borlaza, Hangyul Song, Enrique Cosep, ILHWA SEO, Hyunok Maeng, Minhan Park, Min-Suk Bae, Kihong Park, Gwangju Institute of Science and Technology
Abstract Number: 416 Working Group: Health-Related Aerosols
Abstract Ambient fine particulate matter less than 2.5µm (PM2.5) has gained concern due to its harmful health effects, especially in East Asian countries. In this study, simultaneous measurement of ambient PM2.5 in Beijing, China and Gwangju, Korea was conducted during winter (01.03.2018 – 02.01.2018). Samples were characterized by their chemical properties (ions, elements, and organic and elemental carbon) and their toxicity was assessed by measuring oxidative potential and cytotoxicity. Oxidative potential, the capability of PM2.5 to produce reactive oxygen species which can damage the cells, was measured using dithiothreitol (DTT) assay. Cytotoxicity was analyzed with neutral red uptake (NRU) assay using epithelial lung cells that were exposed to PM2.5 extracts. Average PM2.5 mass concentration in Beijing was higher than Gwangju with values of 62.45 µg/m3 and 26.77 µg/m3, respectively. The contribution of chemical composition for the two sites was also distinct: Beijing (elements (35.9%) > carbonaceous species (OC/EC) (27.9%) > ions (21.7%)) and Gwangju (ions (49.6%) > carbonaceous species (OC/EC) (20.4%) > elements (10.9%)). The average values for the mass- and volume-normalized OP activity (OP-DTTm and OP-DTTv, respectively) were found to be larger in Beijing than Gwangju (OP-DTTm:53.38 pmol/min/µg vs. 44.27 pmol/min/µg and OP-DTTv: 2.48 nmol/min/m3 vs. 1.13 nmol/min/m3, respectively). The difference in OP-DTTm for both sites was not as high compared to the difference in the PM2.5 mass concentration. The OP-DTTm values for event cases were almost the same in both sites (Beijing:55.58 pmol/min/µg and Gwangju:57.91 pmol/min/µg) while OP-DTTv values increased by a factor of 2.5 and 3 for Beijing and Gwangju, respectively, in event days compared to the average values. Cytotoxicity was also determined for the samples from Gwangju where the lowest cell viability was observed with the highest PM2.5 mass concentration. Similar trends were observed for cytotoxicity and OP-DTT in event days but this was not observed for non-event cases. Comprehensive measurement of aerosol effects can be obtained using cytotoxicity analysis, and comparing it with a chemical assay would support the identification of ROS production mechanism and PM components causing aerosol health effects. To further characterize the different factors affecting the OP activity and cytotoxicity and their relationship, the effect of chemical properties of PM2.5 will also be investigated.