Fig 1.
Major components of the Altus Hero I (Hero) mask.
The Hero mask is a battery-powered reusable mask. It consists of a transparent front face panel surrounded by a silicone seal to prevent the leakage of non-disinfected air. It utilizes solid-state Ultraviolet-C emitters to inactivate viral and bacterial pathogens in the unimpeded airflow both entering and exiting the mask through disinfection capsules on the two sides of the front panel. There are Velcro adjustable straps over the head and ears to fasten the mask to the face. There is a light-emitting diode indicator located on the battery compartment that will indicate the system mode and battery status with different colors.
Fig 2.
Mask preferences of subjects for a variety of indicators of comfort and functionality.
Table 1.
Average scores indicating the preference between Hero and N95 from all, female, and male subjects, respectively.
Fig 3.
Examples of thermal images used for facial ratio measurements.
Thermal images of: (A) Subject #7 with a facial ratio of 1.30 which was characterized as short face (ratio < 1.6), (B) Subject #4 with a facial ratio of 1.64 which was characterized as normal face (ratio range 1.6 to 1.699), and (C) Subject #6 with a facial ratio of 1.95 which was characterized as long face (ratio > 1.699). The facial ratio was calculated as vertical direction measurement (total facial height) obtained in pixels over horizontal direction measurement (bizygomatic width).
Fig 4.
Example thermal images when wearing (A) Hero and (B) N95.
Top rows in (A) and (B) are the images for Subject #6, and the bottom rows are the images for Subject #17.
Fig 5.
The mean temperature at each time point while wearing Hero and N95.
Fig 6.
Thermal image analysis for heat intensity and distribution.
(A) Selected (squared) ImageJ region of interest (ROI) of the mask-wearing region on the thermal image of Subject #6 immediately after the exercise when wearing Hero, (B) Color histograms of the ROI in Fig A, (C) Selected ROI of the mask-wearing region on the thermal image of Subject #6 immediately after the exercise when wearing N95, and (D) Color histograms of the ROI in Fig C. The horizontal axis of the histograms represents the intensity, while the vertical axis represents the number of pixels. On the panel below the histograms, the “Mean” shows average intensity values of the “r” (red), “g” (green), and “b” (blue) colors in the ROI. The “SD” is the standard deviation of the intensity of each color. The largest “Mode” value indicates the most frequently occurring color in the ROI.
Table 2.
Temperature comparison based on different facial ratios.
Table 3.
Temperature comparison based on gender.
Fig 7.
The mean blood oxygen levels (oxygen saturation) during the use of Hero and N95 at different time points.