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Assessment of Firearm Noise Exposures and Hearing Loss Prevention

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1.  According to NIOSH approximately how many persons are occupationally exposed to hazardous noise (> 85 dBA Time weighted Average)? 1.2 million 6.4 million 22 million 30 million

2.  In addition to an impulse peak sound pressure level, duration and number of impulses, which of the following is NOT a potential risk factor for noise induced hearing loss? Mixed exposures to other ototoxic agents Features of the waveform such as reflections from nearby objects or kurtosis Combined exposure to continuous and impulse noise Noise levels below 70 dBA

3.  What range of attenuations were measured for persons wearing foam earplugs at various insertion depths (25% to 100%) according to the Air Force data? 2 to 28 dB 2 to 34 dB 19 to 32 dB 2 to 19 dB

4.  Which hearing protection is most effective against reducing harmful noise exposures to firearm noise? Earplugs Electronic hearing protection Earmuffs A hearing protector that is always worn and properly fitted whenever a firearm is being used on a firing range

5.  In addition to noise, what are two exposures at indoor firing ranges that can affect hearing loss for workers and instructors? Hydrogen dioxide and cellulose Mercury and uncombusted propellant Arsenic and hydrogen dioxide exposure Lead and carbon monoxide exposure

6.  Which of the following is NOT a recommended practice for containing exposures to ototoxic elements or gases at a firing range? Sticky mats to remove dust from shoes Positive air pressure within the firing range Separate HVAC systems for range ventilation External exhaust and HEPA filters for range ventilation

7.  When training someone to use hearing protection, which method was the most effective? Provide the user with written instructions Provide the user with a video that shows how to insert earplugs Provide the user earplugs Provide the user individualized instruction on fitting earplugs

8.  In general, which propagation pathway at an indoor firing range affects the users noise exposure the most? Direct exposure pathway from the weapon Reflections from the ground or floor Reflections from any partitions or walls Reflections from the safety ceiling

9.  Which reflection of a gunshot impulse is least likely to increase the noise exposure for a shooter? Reflections from the safety ceiling Reflections from the bullet trap Reflections from the ground/floor Reflections from any partitions or walls

10.  Firearm suppressors can reduce noise of a gunshot impulse. Which feature of the impulse is least affected by the suppressor? The muzzle blast of the weapon Any reflections of the gunshot impulse that return to the shooter's ear Exposures to the side of the firearm and behind the muzzle The ballistic shock wave of a supersonic bullet