Disposable medical protective masks have become a necessity in people's daily lives. According to estimates by the World Health Organization, in 2020, at least 129 billion masks were produced globally, most of which were disposable medical protective masks. If not properly disposed of, these masks will pose a serious threat to the ecological environment.
Waste disposable masks pose a threat to the environment
Disposable medical protective masks are generally composed of three parts: mask, mask strap and nose clip.
The mask part of the mask is generally divided into three layers, the outermost layer, the innermost layer are non-woven fabrics, the middle layer is meltblown cloth. Although these three layers have different names, the main raw material is polypropylene (PP), which is a non-degradable plastic. The main material of the mask strap is polypropylene non-woven fabric, and the nose clip is made of polyethylene (PE) to wrap the fine wire, which also belongs to non-biodegradable plastics. If such masks are thrown into the natural environment, the degradation time may take decades to centuries.
The harm to the ecosystem caused by discarded masks is not only visible to the naked eye. The fibers of meltblown and non-woven fabrics are extremely fine in diameter compared to other materials, and the use of masks intensifies the mechanical wear and tear between the fibers, resulting in the formation of more microplastics. Studies have shown that the average release of microplastics from unused masks is 71-308 microplastics per mask; for used masks, the average release of microplastics increases to 682-1918 microplastics per mask. In the ocean, these microplastics are easily ingested by fish, shrimp and other organisms, thus entering the food chain and eventually the human body.
Therefore, the use of biodegradable materials to make masks can effectively alleviate the pressure of discarded masks on the ecological environment. By replacing polypropylene with the bio-based biodegradable material PLA, masks made from this material can decompose into water and carbon dioxide in the natural environment without adding to the ecological burden. At normal temperatures and humidity, PLA and its products are quite stable. However, in natural environments with certain temperatures and humidity, such as in sand, silt and seawater, PLA can be completely degraded by microorganisms in nature and finally decompose into water and carbon dioxide.
