| Title: | Role of semi-volatile particulate matter in gas-particle partitioning leading to change in oxidative potential |
| Author(s): | Gali NK; Stevanovic S; Brown RA; Ristovski Z; Ning Z; |
| Address: | "Division of Environment and Sustainability, Hong Kong University of Science and Technology, Hong Kong. School of Engineering, Faculty of Science and Build Environment, Deakin University, Victoria, Australia. International Laboratory of Air Quality and Health, Queensland University of Technology, Queensland, 4001, Australia. Division of Environment and Sustainability, Hong Kong University of Science and Technology, Hong Kong; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Hong Kong. Electronic address: zhining@ust.hk" |
| DOI: | 10.1016/j.envpol.2020.116061 |
| ISSN/ISBN: | 1873-6424 (Electronic) 0269-7491 (Linking) |
| Abstract: | "Atmospheric semi-volatile organic compounds (SVOCs) are complex in their chemical and toxicological characteristics with sources from both primary combustion emissions and secondary oxygenated aerosol formation processes. In this study, thermal desorption of PM(2.5) in association with online measurement of reactive oxygen species (ROS) was carried out to study the role of SVOCs in its gas-particle partitioning. The mass concentrations of PM(2.5), black carbon (BC) and p-PAHs downstream of a thermodenuder were measured online at different temperature settings (25, 50, 100, and 200 degrees C) to characterize PM physico-chemical properties. While the mass concentrations of PM(2.5) and p-PAHs reduced to approximately 34% at 200 degrees C compared to that in ambient temperature, BC mass concentration has decreased by 30% at the highest temperature. Furthermore, the submicron particle size distribution showed reduced particle number concentration in Aitken mode at 200 degrees C heating. The ROS, measured by Particle-into-Nitroxide-Quencher, also showed reduction and followed a similar trend with PM measurements, where the total ROS decreased by 12%, 31%, and 53% at 50 degrees C, 100 degrees C, and 200 degrees C, respectively, compared to the ambient sample. When a HEPA filter was included in the upstream of samples, 39% of gas phase ROS reduction was observed at 200 degrees C. This provided a good estimate of the contribution of SVOCs in ROS production in PM(2.5), where decreased SVOCs concentration at 200 degrees C increased the percentage of particle surface area. This concludes that the surface chemistry of these organic coatings on the particles is important for assessing the health impacts of PM" |
| Keywords: | Aerosols *Air Pollutants/analysis Environmental Monitoring Oxidative Stress Particle Size Particulate Matter/analysis *Volatile Organic Compounds/analysis Oxidative potential Particle-into-Nitroxide-Quencher Particulate matter Thermodenuder; |
| Notes: | "MedlineGali, Nirmal Kumar Stevanovic, Svetlana Brown, Reece Alexander Ristovski, Zoran Ning, Zhi eng England 2020/11/22 Environ Pollut. 2021 Feb 1; 270:116061. doi: 10.1016/j.envpol.2020.116061. Epub 2020 Nov 11" |
