It is very reasonable
to be concerned about
the adverse effects,
on human health,
caused by wind turbine
infrasound.
Infrasound is
officially classified
as any noise
with frequencies
less than 20 Hertz
( twenty cycles per second ).
As an audiophile
since the 1960's,
I know frequencies
between 20 and 30Hz.
are mainly felt,
not heard, so they
should have the
same health effects
as noise under 20Hz.
As a member
of an audio club,
from the mid-1980s
to mid-1990s.
I had the opportunity
to hear do-it-yourself
subwoofer designs
by audio engineers,
that could produce
infrasound at high
sound pressure levels.
I found out my body
hated infrasound,
only after I was
driven out of a
well sealed home,
by a subwoofer
consisting of twelve
high displacement 15"
bass drivers -- but
then I noticed that
most club members
were not bothered
by that infrasound
( included in carefully
selected music CDs,
and test tone CDs --
probably less obnoxious
than wind turbine noise ).
There is disturbing
information I found
about infrasound
damage to pets
and wildlife.
According to Hearing
Health USA website,
scientific studies show
that dogs, cats, and
horses have better
hearing than humans.
Wind energy developments
tend to be on rural lands,
in the vicinity of farm animals.
What has been classified
as infrasound for humans
-- below the ear's
hearing range --
can be very audible
to animals with a
wider hearing range.
Back in 1996, Dr. Sherri Motzel
at Merck Research Laboratories
provided evidence that rats
who were unintentionally exposed
to infrasound (a malfunctioning
ventilation system) suffered from
a variety of effects (water intake,
blood pressure, reproduction,
glucose metabolism, and
immune function.)
Animals known to be
able to hear infrasound
include cows, cuttlefish,
ferret, goldfish, horses,
octopi, pigeons, rock doves,
squid, and whales.
Species such as alligators,
elephants, giraffe,
hippopotamus, okapi,
and rhinoceros use
infrasound frequencies
in their communications.
When a record-breaking
twenty-nine sperm whales
beached themselves
on North Sea shores
in 2016,
Utrecht University
in the Netherlands
performed studies
on the cause of death.
The cause of death
was declared t
to be unknown.
But not studied
were the massive
offshore wind turbines
located near where
the whales died.
Important honey bee
communication takes place
between 12-13 Hertz.
How the production of infrasound
from wind turbines might effect
their ability to communicate
directions may represent a threat
to bee populations and pollination,
and needs to be investigated.
Infrasound produces
vibrations in the
inner ear canal that
cause stress to the brain.
For me, infrasound
vibrations on my body
cause 'stress' in my
stomach, and other
internal organs.
An unclassified
military study
conducted in Portugal
over a 20-year period
was titled,
“Low Frequency Noise:
A Major Risk Factor
in Military Operations.”
According to that
medical study,
70% of individuals
are susceptible
to the development of
Vibroacoustic Disease
due to the cumulative effects
of noises below the threshold
of human hearing.
Military studies
conducted in the U.S.
support the Portugal study.
Such adverse effects
have been documented
among pilots and other
members of flight crews,
continuously exposed to
infrasound noise from
the spinning of jet turbines
or propellers.
Some cases cited
in the Portuguese study
included data showing that
10% of workers who were
regularly exposed to infrasound
in an aeronautical plant
developed late-onset epilepsy,
at a rate fifty times higher
than what would be diagnosed
in a general population.
From other studies:
Using electron microscopes,
researchers found that among
infrasound exposed populations,
low frequency noise damage
appears to target the
respiratory system,
causing bronchitis,
recurring infections
of the oropharynx,
and pleural effusion.
High resolution CT scans
identified atypical instances
of lung fibrosis among
non-smokers.
Cardiovascular diseases
represent a significant threat
from infrasound where the
thickening of the pericardium
is known as a hallmark
of Vibroacoustic Disease.
That thickening acts
like a blanket,
that covers
the walls of major
blood vessels,
pericardia, aortic
and mitral valves,
and carotid arteries,
diminishing their
effectiveness.
Most evidence that exists
on the pathogenic effects
of infrasound are about
infrasound sources
other than wind turbines
-- but turbines produce
infrasound in the same
frequency range as
the other sources.
In 2018, the World
Health Organization
finally published n
ew environmental
noise guidelines.
The WHO report said:
“Wind turbines
can generate
infrasound or
lower frequencies
of sound than
traffic sources.”
“ ... the repetitive nature
of the sound
of the rotating blades
and atmospheric influence
leading to a variability
of amplitude modulation …
can be a source
of above average
annoyance.”
“Standard methods
of measuring
sound, most commonly
including A-weighting,
may not capture the
low-frequency sound
and amplitude modulation
characteristic of
wind turbine noise.”
“Wind turbines are not
a recent phenomenon,
but their quantity, size
and type have increased
significantly over recent
years.
As they are often built
in the middle of otherwise
quiet and natural areas,
they can adversely affect
the integrity of a site.”
They also admitted,
unfortunately,
that the HMO was
“not aware of any
existing interventions
… to reduce harms
from wind turbine noise.”