Speech Impaired by Half Masks Used for the Respiratory Tract Protection

Area of Science:

• Occupational Health and Safety
• Acoustics
• Respiratory Protection

Background:

• Filtering facepiece respirators (FFPs) are essential personal protective equipment.
• While protecting the respiratory tract, FFPs can impede breathing and suppress speech.
• The impact of FFPs on speech intelligibility requires objective acoustic analysis.

Purpose of the Study:

• To objectively measure sound attenuation by various filtering facepiece respirators (FFPs).
• To assess the effect of FFPs on speech frequencies critical for intelligibility.
• To determine if filtration efficiency influences acoustic suppression.

Main Methods:

• Utilized a white noise and artificial speech generator covered by different FFPs.
• Measured sound pressure levels in 1/3 octave bands (100 Hz-20 kHz) using a Class 1 sound level meter.
• Recorded acoustic data at distances of 1-5 meters from the sound source.

Main Results:

• All tested FFPs attenuated sound frequencies of 1 kHz and higher, particularly the 2 kHz band.
• Higher filtration efficiency FFPs demonstrated greater sound attenuation.
• FFPs altered voice timbre due to frequency-dependent attenuation, impacting speech clarity.

Conclusions:

• Filtering facepiece respirators significantly impede speech intelligibility.
• The frequency-dependent sound suppression by FFPs, especially those with higher filtration, is a key factor.
• Workplace communication may be compromised by the acoustic effects of FFPs.