Craniofacial Dimensions as Determinants of the Fitted Performance of Common Face Masks (FACEFIT 2.0)

This study examines the role of craniofacial dimensions and self-evaluation thereof in the protection afforded by masks commonly worn by the public as protection against aerosol contaminants. The effectiveness of instructions for self-evaluation of craniofacial dimensions will be tested against standard digital and manual craniometric methods.

Approximately 500 (18-70 year old) subjects.

After consenting to participate in the study, subjects will use a short self-assessment questionnaire to measure their craniofacial dimensions, and have their face measured using standard anthropological techniques and a 3D camera. They will then enter a chamber containing an atmosphere of aerosolized salt particles where the fitted filtering efficiency of 2 types of face masks will be measured briefly. Participation time is approximately 60 minutes.

Wearing a face mask is a primary protection strategy against airborne infectious agents as well as toxic aerosols such as wildfire smoke. Despite the ubiquitous presence of masks in public life in recent years, the average person has a poor understanding of factors that influence the fitted performance of the face coverings that they wear. This problem is exacerbated by the lack of mask fit testing available to the public outside of occupational settings subject to regulation. As a result, the vast majority of the population currently wears masks with limited knowledge of their efficacy or the means to acquire it. A simple, validated method to quantitatively self-assess individual craniofacial dimensions relative to that of the general population will permit members of the public to make informed decisions about the types of mask that they wear in specific risk situations, and whether to use fit enhancements to optimize their fitted performance. In addition to limiting the morbidity associated with exposure to poor air quality, an individualized improvement in the efficacy of mask will have a multiplicative effect in the prevention of the transmission of infectious vectors.

Subjects who are not excluded from the initial screening will be scheduled for consenting at the EPA Human Studies Facility (HSF). At the start of the visit, the study protocol will be outlined, and informed consent obtained to initiate enrollment into the study. There will be one session in this study. Consenting subjects will proceed immediately to the participation phase.

Consenting: There will be one (1) study consent form (form FF2 1). This consent form must be signed by the participant and the study team member obtaining informed consent. The subjects may ask any questions they have regarding their participation in the study at any time prior to or during their participation. Persons with child-bearing potential will be required to self-administer a pregnancy test in a private bathroom. Those who self-administer a pregnancy test will have to confirm the results on the consent form in order to proceed to the study phase.

Behavioral questionnaire: Subjects will complete a short questionnaire (Form FF2.0 2) that asks about their predisposition to wear a face mask under a variety of scenarios. This information will be used to guide public health communications during air quality emergencies.

Assessment of self-evaluation instructions for craniofacial measurements: Subjects will use instructions presented in a self-evaluation form (Form FF2 3) to measure their own craniofacial dimensions using the rulers provided and a mirror. Subjects will receive no assistance with completing the self-assessment form. At intervals of approximately, 10-40 subjects, measurements obtained in the self-evaluation will be compared to the craniofacial measurements obtained by a study team member. The results of the comparison will be used to guide revisions of the instruction in the self-evaluation form in an iterative manner. The protocol will be amended accordingly to update changes to the self-evaluation instructions.

Craniofacial measurements: A 3 D scan of the subjects' face and head will be obtained by aligning the head inside of an oval shown on a tablet screen. The image takes about 3 seconds to generate and subjects will be asked to move their head slightly. In addition, manual measurement of 4-8 craniofacial dimensions will be taken by a study team member using calipers and a tape measure.

Lung Function Test. Participants will complete a breathing test (peak flow meter) before and after the facemask testing. Study personnel will coach the participant to take a full breath in and then blow it out as hard and fast as they can. They may be asked to do this up to five times. This test measures the volume of air they can blow out (exhale) quickly after taking a very deep breath. This is a method to measure lung function before and after the testing procedure for safety purposes. The investigators will stop the study and not complete the mask fit testing if the participant's peak expiratory flow (as measured with the peak flow meter) is not ≥ 80.0% of their predicted value based on their age, height, and weight.

Assessment of filtering face piece (FFP) use: The range of variability that exists in the subject population while wearing two different types of face coverings will be assessed. Masks will consist of a KN95 mask and a surgical/procedure mask. The fitted filtration efficiency of each mask will be measured using aerosolized sodium chloride particles (mean aerodynamic diameter 0.040 microns) emitted by a particle generator. During the fit testing, the concentration of aerosolized saline particles emitted by a TSI Particle Generator will be approximately 5000-30000 particles/cc of air. The temperature in the chamber will vary between 20 and 30 oC, the relative humidity will be maintained at approximately 50 %.

The subject will remain seated in the chamber and complete a modified version the Occupational Safety and Health Administration Quantitative Fit Testing Protocol (Modified Ambient Aerosol CNC Quantitative Fit Testing Protocol for Filtering Facepiece TableA-2-RESPIRATORS). The subject will then move their head from left to right, taking two breaths at each extreme for 30 seconds. This will be followed by moving the head up and down, taking two beaths at each extreme for 30 seconds. The procedure will be repeated after the addition of a clip to the ear-loops of the mask behind the neck of the subject. In total, the testing time for the 2 masks with and without clip will be approximately 6 minutes.

Eligibility Criteria:
Inclusion Criteria:

1. Age 18-70 years old healthy of any gender and ethnicity.
2. Subjects must be ambulatory and tolerate enclosed spaces.
3. Subjects must report being in good health
4. Individuals with a BMI (kg/m2) that is greater than 16.0 and less than 50.0

Exclusion Criteria:

1. Persons who are pregnant, attempting to become pregnant or breastfeeding
2. Persons who are unable to read English or Spanish well enough to follow written instructions or a questionnaire.
3. Persons who have facial hair.
4. Individuals who have had an acute respiratory illness within 4 weeks.
5. Individuals who have active allergies.
6. Those who are not feeling well.
7. Anyone who is unable to walk unassisted, stand or sit still for 15 minutes at a time.
8. Anyone who suffered a heart attack, cardiac arrest or stroke in the past 6 months.
9. Anyone who has been hospitalized overnight or sought urgent medical care in the last 30 days.
10. Anyone who has an unspecified illness, which in the judgment of the medical staff, might increase the risk associated with this study will be a basis for exclusion.
11. Those who are pregnant, attempting to become pregnant or breastfeeding.