Micro- and Nanoplastic Particles from an Atmospheric Perspective
YUE ZHANG, Arthur W. H. Chan, Andrew Ault, Jonathan Slade, Sining Niu, Sahir Gagan, Zezhen Cheng, Alana Dodero, Ruizhe Liu, Qian Zhao, Qi Ying, Xingmao Ma, Swarup China, Manjula Canagaratna, Texas A&M University
Abstract Number: 540
Working Group: Chemicals of Emerging Concern in Aerosol: Sources, Transformations, and Impacts
Abstract
The prevalence of the micro- and nanoplastics detected in the ecosystem is an emerging problem worldwide. Comparing with micro- and nanoplastics particles (MNPPs) in other environmental systems, atmospheric MNPPs can significantly facilitate the long range transportation of environmental plastics while contributing to climate forcing.
Despite their increasing importance, the sources, concentrations, processing, and impacts of atmospheric MNPPs are still not well understood. Herein, this presentation will first provide an overview of MNPPs, followed by how atmospheric tools can be used to address unique scientific questions that need urgent answers to improve understanding of the source, processes, and impacts of atmospheric MNPPs.
The presentation will then introduce the first study to quantify real-time nanoplastics concentrations in the atmosphere and its potential applications. A high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is employed to detect several most abundant types of submicron plastic particles. The results are validated by prolysis gas chromatopgraphy mass spectrometry (Py-GC-MS). Ambient particles are also collected and analyzed by a constrained PMF (multilinear engine, ME-2) method to determine the temporal distribution of nanoplastic particles. A distinct factor highly correlated to the pure (polystryene) PS profile is separated, with the mass concentration of PS nanoplastic particles is estimated to be 10-50 ng/m3 during the ambient sampling period.
The presentation will then move onto the atmospheric processing of MNPP, including the aging and lifetime of PS particles through reacting with common atmospheric oxidants such as hydroxyl radicals (OH·), ozone, and UV light. The pseudo first order rate constant of PS particles against OH· radicals, kPS, is quantified to be, 1.374×10-13 cm3 molecule-1 s-1 while the ozonolysis and photolysis rates were negligible. Additionally, the atmospheric lifetime of MNPPs is determined to be much shorter compared with the lifetime of MNPPs in other media. The hygroscopcity of MNPPs will also be shown to creases as a function of aging, suggesting oxidized functional groups forming on the surface of the MNPPs.
To sum up, recent advancements in atmospheric MNPPs further suggest that characterizing their concentration and processes may bridge important gaps in understanding their long range transportation abilities, environmental persistence, health implications, and potential contribution to climate forcing.