Abstract View
Discovery of Atmospheric Microplastics in Urban Emissions
ANA MORALES, Jay Tomlin, Yoorae Noh, Andrew Whelton, Alexander Laskin, Purdue University
Abstract Number: 332
Working Group: Urban Aerosols
Abstract
Micrometer and nanometer plastics (MNP) have become substantial environmental pollutants because of increased production and poor disposal management of various plastic products degrading in the environment. MNP particles were also recently deemed an emergent component of air pollution due to their ability to become airborne and undergo long-range atmospheric transport. Here, we reveal a substantial, yet unreported, source of atmospheric MNP in an urban area. The MNP were discovered in samples of steam water emitted at urban sewer repair sites, where the technique called plastic cured-in-place-pipes (CIPP) was employed. The CIPP installation procedure involves the chemical manufacture of a new plastic pipe inside an existing damaged pipe by blowing steam through the pipe, resulting in the release of MNP and other chemicals into the air. Optical imaging of MNP particles suspended in the steam water using a nano FlowCamTM showed a bimodal particle size distribution with the characteristic mean diameters of 300 nm and 3 μm, where particles of smaller mode exhibited high circularity and particles of larger mode showed substantial fractal dimensions. Electron microscopy analysis of the dry aerosol particles generated from the steam water showed abundant presence of even smaller MNP particles in the size range of 100-200 nm size, where smaller particles showed a higher degree of oxygenation. We investigated the chemical composition of MNP emitted during CIPP operations by employing multi-modal chemical imaging using SEM, Raman, and soft X-ray spectro-microscopy. This work provides a detailed description on the chemical composition of individual MNP particles related to CIPP manufacture, which is important in evaluating their contributions to urban environment.