Recent advances in facemask devices for in vivo sampling of human exhaled breath aerosols and inhalable environmental exposures

Abstract

Since the COVID-19 pandemic, the unprecedented use of facemasks has been requiring for wearing in daily life. By wearing facemask, human exhaled breath aerosols and inhaled environmental exposures can be efficiently filtered and thus various filtration residues can be deposited in facemask. Therefore, facemask could be a simple, wearable, in vivo, onsite and noninvasive sampler for collecting exhaled and inhalable compositions, and gain new insights into human health and environmental exposure. In this review, the recent advances in developments and applications of in vivo facemask sampling of human exhaled bacteria, viruses, proteins, and metabolites, and inhalable facemask contaminants and air pollutants, are reviewed. New features of facemask sampling are highlighted. The perspectives and challenges on further development and potential applications of facemask devices are also discussed.

Keywords: Breath analysis; Breath sampling; COVID-19; Environmental exposures; Exhaled breath; Facemask; In vivo sampling; Inhalable exposures; Inhaled air; SARS-CoV-2.

Graphical abstract

Fig. 1

Number of Publications per year on facemask for nearly a century. Number of publications obtained on Science Citation Index (Web of Science) with the following query: “face mask” or “facemask” from 1920 to 2021 (access on Mar 1, 2022).

Fig. 2

Relative size chart of human exhaled aerosols and inhalable contaminants and the pore size of typical facemasks (diagrams not to scale).

Fig. 3

Workflow of analytical procedures of human exhaled and inhalable substances with facemask sampling. Solid lines show the conventional processes for chemical and biological analysis, and dotted lines show an optional process for direct sampling (e.g., extracting analyte with adsorbent materials that was fixed in the facemask) and direct sample analysis (e.g., direct MS and sensors).

Fig. 4

Representative facemask devices for in vivo sampling of human exhaled breath aerosol: a) FFP3 facemask with a filter, reproduced from Ref. [28] with permission, b) FFP1 facemask with gelatin filter, reproduced from Ref. [32] with permission; c) surgical facemask with dog-bone specimen, reproduced from Ref. [33] with permission; d) Duckbill face mask fitted with PVA matrices, reproduced from Ref. [49] with permission; e) A filter held by a CPAP-type face mask, reproduced from Ref. [51] with permission, f) Wearable collector with facemask, reproduced from Ref. [53] with permission. g) Paper facemask, reproduced from Ref. [60] with permission h) hard-surface plastic facemask, reproduced from Ref. [60] with permission; i) SPME fibers in KN95 facemask, reproduced from Ref. [46] with permission; j) paper strips in KN95 facemask, reproduced from Ref. [62] with permission.

Fig. 5

Representative facemask devices for in vivo sampling of human inhalable aerosols: a) Inhalation experiments in indoors with facemasks M7 and M10, reproduce from Ref. [86] with permission, b) inhalation experiments at outdoors with facemasks M12 and M18, reproduced from Ref. [86] with permission; c) a miniature sampler in a FFP3 facemask, reproduced from Ref. [99] with permission; d) two miniature samplers in FFP3 facemask, reproduced from Ref. [100] with permission; e) facemask expose to airborne polycyclic aromatic hydrocarbons, reproduced from Ref. [101] with permission; f) facemask expose to tobacco smoke, reproduced from Ref. [102] with permission; g) paper strip outside in facemask to expose ambient air, reproduced from Ref. [77] with permission.