Carbonaceous aerosol from the thermal degradation of plastics through atmospheric oxidation: Airborne particle method development

Nanoplastics, known but not well studied pollutants, can be aerosolized and have the potential to spread widely in the atmosphere with residence times on the order of weeks. The bleaching of nanoplastics is of interest due to the main climate contributions of aerosol particles’ relation to light absorption and scattering. An experiment was designed to study the bleaching of Red PETG 3-D printing filament by oxidation (ozone exposure). To that end, an experimental apparatus comprised of mixing volumes, desiccants, filters, a tube furnace, ozone generator, smog chamber, ozone analyzer, Photoacoustic Extinctiometer (PAX), and Scanning Mobility Particle Sizer (SMPS), among other tubing and connection hardware was developed. Aerosolized plastics nanoparticles of the dyed PETG filament after thermal degradation were injected to the smog chamber for study during their residence time in the smog chamber gas volume. Results are inconclusive for oxidation experiments, due to difficulty with the magnitude of bleaching due to ozone when compared to noise introduced by size distribution evolution. Next steps for the developed experimental apparatus, injection methods, and data collection procedures include trying alternative (more robust) aging mechanisms. Aging by introduction of hydroxyl radical injection from photolysis of hydrogen peroxide is one specifically promising alternative.