Complex Geometries for Extended Wear Respirators Towards Regenerable Particulate Matter Protection

Objective: Develop a rugged, 3D printable PFAS-free particulate filtration impactor system that readily attaches to a respirator/mask and is suitable for extended wear in military operational environments with high particulate matter levels during aerobic activity. Description: Warfighters can be deployed in operational environments with high airborne particulate matter (PM) levels; these events lead to a significant risk of developing cardiovascular and pulmonary disease. Adverse health effects, including cardiovascular and pulmonary disease, are well-documented consequences of exposure to high levels of PM with aerodynamic diameters of less than 10 μm (PM10) and especially less than 2.5 μm (PM2.5). In many deployment environments as well as in training facilities (e.g., indoor firing ranges and shoot houses), military personnel are continually exposed to levels of PM that exceed the military exposure guidelines (MEG).1 These levels can be greatly exaggerated by anthropogenic activity when exposed to lead residue, burn pits, or dust storms. Unfortunately, current particulate filtration technologies are not idealized for extended wear during military operations. A high burden is associated with utilizing current protective gear while participating in high levels of aerobic activity. The primary complaint that limits use of masks and respirators is discomfort caused by breathing resistance. Due to the extreme levels of PM in some deployed settings, there is the recurring issue of clogging, which further increases breathing resistance and wearer burden. Current filtering equipment is single use, which adds an additional logistics burden when masks/filters need to be continually replaced. Furthermore, many current technologies that provide inhalation protection from particulates utilize HEPA/HESPA media, which can contain PFAS materials. With the environmental and long-term health concerns and regulations facing industries, many manufacturers have announced they are moving away from producing PFAS containing materials – this shift could result in a breakdown in the supply chain of particulate matter protection without the development of suitable alternatives. The objective of this effort is to develop a rugged, novel particulate impactor system that can readily be manufactured at the point of need and attached to current respirators, such as the M50 respirator, commercial half-masks, P100-style masks, and/or balaclava masks and be regenerated after use. This particulate impactor system should be able to trap aerosols upon inhalation. After use, filter media should be capable of regeneration via the removal of any captured PM, allowing the filter to be used again. Here, regeneration refers to the removal of trapped particles after use such that all channels are cleared, and regeneration may be achieved by a secondary step such as reversed air flow through the media from compressed air. Additionally, the ideal system should be able to allow high flow volumes with minimal breathing resistance and should be suitable for wear during aerobic activity. It must also be resistant to clogging and not rely on PFAS-containing media. Technologies utilizing the complex geometries that are enabled by additive manufacturing offer a promising solution towards this mission space due to complex geometries such as lattice structures offering filtration mechanisms such as impaction.2 Additionally, additive manufacturing of this technology enables this novel particulate-focused filtration solution to be manufactured in a forward deployed environment. Technologies that meet the performance criteria will be considered; however, priority shall be given to innovative or novel designs with minimal size and weight, adaptable to respirator/filter design, able to be manufactured under contested logistics, fully self-contained, able to regenerate after use, and have minimal to no power requirements. Keywords: Respirator, Particulates, Aerosol, Individual Protection, Advanced Manufacturing, Forward Deployed