Feasibility of biodegradable material polylactic acid as a substitute for polypropylene for disposable medical masks production verified by life cycle assessment

The Corona Virus disease 2019 (COVID-19) outbreak has changed the lifestyles of billions of people. Face masks, as a daily protective tool, have become a must-have item. The number of masks discarded has soared, making environmental and hygiene problems impossible to ignore. The rapid development of biodegradable materials may be one of the solutions to this issue. In this study, life cycle assessment (LCA) was used as a method to quantitatively analyze the environmental impacts of two disposable medical masks, biodegradable polylactic acid (PLA) and fossil-based polypropylene (PP). The results show that human toxicity (63.93%), acidification (39.93%), global warming potential (36.29%), and abiotic depletion (83.55%) of disposable medical masks mainly made of PLA were significantly lower than those of PP. While the photochemical oxidation (4.89%) for PLA masks was slightly higher. The manufacturing cost per unit hour was 0.060 yuan (PP) and 0.0675 yuan (PLA). It was estimated that the replacement could reduce global carbon emissions by 321,392,700 tons and 466,400 tons for China. Furthermore, the process improvements in the raw material acquisition stage could maximize the benefits of carbon reduction.