This urgent need, as we point out in the manuscript title, stems from the fact that a regulatory gap widely exists in current quality standards and regulations on masks and respirators. By surveying the relevant ASTM, NOISH, EU, China, and ISO standards, as listed in the manuscript, we found no regulation or recommendation pertinent to this type of respirable hazard. Non-medical substitutes, such as face coverings, are also subject to such risks if made with improper household materials.
There are numerous studies on assessing the filtration efficiency of masks, respirators, and recently, cloth face coverings (ACS Nano, 2020, 14, 6339; Nano Lett, 2020, 10.1021/acs.nanolett.0c02211). This particular issue, however, has been widely neglected by the scientific community. Studies on masks and respirators as a source of respirable debris were found to be anecdotal (Ann. Occup. Hyg. 1986, 20, 131−133). Recent discussions on disposable masks and respirators focused on their widespread use during the current pandemic and disposal into the environment (Sci Total Environ 2020, 737:140279; Waste Manage 2020, 108, 202-205).
By putting several top-selling medical face masks and N95 respirators under microscopes, we found plenty of micro(nano)plastic debris on their inner facings, with some appearing to be loosely attached while others still connected to their structural fibers. The two types of debris often appear in the same cluster with similar morphology and texture. Figure 1 in the manuscript shows examples of these, and we have submitted a file containing additional images with methods and QA/QC as further evidence.
the novel coronavirus still looming in our communities, there is a strong ongoing
demand for personal respiratory protection devices. Supported by the latest guidance from WHO, many regulatory
bodies have made these a compulsory requirement for the public when using
public transport, or in certain settings where it is difficult to maintain adequate
physical distancing. Respirable hazards such as micro(nano)plastics in
these, if pervasively exist, may pose a public health concern. Children, the elderly,
and individuals having chronic respiratory diseases may be particularly
sensitive to this type of inhalable contaminants. With a growing body of
evidence on their adverse effects, micro(nano)plastics is an active research
domain with a quickly expanding scope. Researchers studying their inhalation, via
atmospheric or other anthropogenic sources, are now facing the reality that
there is a piece of plastic garment on top of the mouth and nose of millions of
people every day. With these becoming a necessity for many in their daily life
and work, questions must be raised over this apparent regulatory gap concerning
their long-term use safety. The current pandemic, if anything, should bring this
particular issue under scrutiny.