Hearing Health Summer 2015 Issue Summer 2015 | Page 13

hearing health

In the April 2014 issue of the Journal
of the Acoustical Society of America,
NIOSH researchers said these Apple
iOS apps provided the most accurate
sound level measurements: NoiSee
by Noise Lab ($1), Noise Hunter by

The Best
Apps for
Measuring
Decibels

Inter•net2day ($6), and SoundMeter by
Faber Acoustical ($20). Android apps
were not included, they said, because
Android devices had uneven conformity
and the apps lacked the features and
functionalities found in Apple iOS apps.

Dry, Clean Hands May Come at a Price
It’s not your imagination. Super-strong electric hand dryers are definitely as loud as you think.
By Shari Salzhauer Berkowitz

P

ublic restrooms nowadays are more likely to have
high-airflow electric hand dryers instead of paper
towel dispensers, in order to provide a hygienic,
fast, and environmentally friendly way to dry your hands.
Although bathrooms with these electric hand dryers do
save paper, many people find the loud noise that emanates
from them to be irritating.
The noise is worse if you have a hearing problem. Some
people complain that the dryers aggravate their tinnitus
(ringing or buzzing in the ear). Those with hyperacusis,
or sensitivity to loud noises, may also suffer. And for
custodial workers, who are likely exposed to the sound
of dryers for cumulative hours per day, the dryers may
actually be an occupational hazard.
My post-baccalaureate students and I examined the
decibel output of three common high-airflow hand dryers
and published our research in the March-April 2015 issue
of the journal Noise & Health. We measured hand dryers
around Mercy College in Dobbs Ferry, New York, using a
Radio Shack sound level meter to take readings at 2.5 feet
(about arm’s length), 5 feet, and 10 feet.
We found that the sound generated by the machines—
the Dyson Airblade, the Excel Dryer Xlerator, and the
World Dryer Airforce—was over 80 decibels (dB), even
at 10 feet away. The loudest sound recorded was 94 dB—
about as loud as a subway train. The Occupational Safety
and Health Administration says workers should not be
exposed to more than 90 dB for eight continuous hours.
Unlike loud sounds in other settings, in these restrooms
the noise of the dryers does not dissipate the farther you
are from the source. We believe this is because of the high
level of reverberation off the hard surfaces—tile, glass,
concrete—commonly used in restrooms.
Of course the hand dryers do not run continuously. But

a maintenance worker whose duties may include other
noisy tasks—vacuuming, cutting grass, snow blowing—
as well as cleaning bathrooms is at risk for hearing loss.
Why are these hand dryers so loud? It is to generate
enough high-velocity airflow to quickly dry your hands.
Jet engines also need to generate airflow, and think of
how loud those are.
A state senator in Oregon is trying to pass legislation
restricting the use of high-airflow hand dryers, and my
students and I are undertaking a follow-up study of
additional hand dryers to determine how they are actually
used by patrons. For example, the manufacturers estimate
they are used for 10 to 15 seconds per patron, but is that
true? Is the dryer noise nearly constant in a busy restroom?
That is part of what we aim to find out.
Aside from wiping your hands on your pants and
making a quick exit, you can take these steps:
*