UV-induced release and characterization of dissolved organic matter from disposable face mask layers and polypropylene.

The global use of disposable facemasks (FMs), particularly during the COVID-19 pandemic, has raised environmental concerns. However, there is limited understanding of the weathering products and chemical characteristics of dissolved organic matter (DOM) released from disposable FMs, including surgical (SFM), KN95, and N95. This study presents the first ply-specific investigation into the yields and chemical properties of DOM from these facemasks, alongside reference polypropylene (PP) microplastics, under UV-irradiation. All mask layers and PP microbeads showed significant continuous DOM release, with SFM and certain N95 layers (notably N95-1 and N95-2) exhibiting higher DOM yields. The yields and chemical properties of DOM are related to material composition of fibers and manufacturing procedures. In addition, UV-exposure generally led to decreased molecular weight and aromaticity of released-DOM, indicating concurrent production and degradation processes. The released-DOM had a size ranging from 200 to 1800 nm and was predominantly negatively charged. Surface morphological changes, observed via SEM, revealed fragmentation after UV-irradiation. EEM-FARAFAC analysis identified two protein-like and one humic-like fluorescent components, with mask-specific variations. This study enhances understanding of the photochemical behavior and degradation products and their chemical properties of different mask layers, offering insights into the fate and environmental impact of disposable masks in aquatic ecosystems.