Loud sounds can significantly affect hearing, and the ones we don’t hear may be more harmful.

“And the vision that was planted in my brain
Still remains
Within the sound of silence.”

The words are from the Simon & Garfunkel song, Sounds of Silence. They sang about another silence, but all of us need to consider the sound in the silence that may assault our ears and our health. No, you don’t hear it, just as you don’t see viruses floating around you, but they are both there, and both of them can cause harm to you.

Environmentalists have found that diesel fuel pollutes the air and contributes to climate change. Seeking additional forms of renewable energy production, the environmentalist and researchers have determined that there are several that might be useful. The new sources include wind, ocean, hydropower, solar, bioenergy, and geothermal.

What about wind? We can depend on that in areas where the winds blow furiously for much of the day. Converting hidden gusts into electricity and transmitting it appears to be a logical answer to the energy problem faced by power plants, homes, and governments. But wind isn't the benign solution we would like to think it is and wind turbines in the sea or on the land, raise little concerns for most of us. Regrettably, we are displaying our naivety in this matter, and researchers have recently raised concerns.

For a moment, let's consider our hearing and what is the normal level at which sound can be heard comfortably and without doing any injury to us.

Decibels are the standard units of sound measurement. In most cases, it is safe to listen to sounds that are 70 dBA or below. Hearing loss can occur after prolonged or recurrent exposure to noises that are 85 dBA or louder. How many well-known entertainers have lost their hearing? I can think of at least two very well-known: Phil Collins (who played drums besides singing) and Huey Lewis, who was a singer with the “News."

Some of the normal sound-producing activities we will experience include:

Normal conversation: 60–70 dBA
Lawnmowers: 80 to 100 dBA
Sports events: 94 to 110 dBA
Sirens from emergency vehicles: 110 to 129 dBA
Fireworks: 140 to 160 dBA

These are the sounds that we easily become aware of, but they are not the other sounds that may cause health difficulties, even though they are not within our normal range of hearing.

Among the most evasive types of noise are those with a low frequency or pitch. Outside of occupational settings, officials mostly ignore them and find it difficult to quantify using traditional methods.

Despite the lack of interest or ability to monitor, people are reporting physical problems related to sound. We should also think about psychological difficulties that may be connected to this.

Many have reported experiencing headaches, anxiety, heart palpitations, and sleep problems due to sounds that not everyone can hear. Additionally, some people wonder if these symptoms are mental or physical. We know less about and have done less research on low-frequency noise than other types of noise. Now it's time to take a look at an innocuous, supposedly environmentally safe, producer of low frequencies sounds that may be harmful to us.

What about land-based wind turbines? Protesters worldwide often voice worries about the potential health effects of these turbines. Some people have reported physical symptoms such as headaches, chronic discomfort, high blood pressure, and trouble sleeping due to wind projects close to their homes, as opposed to offshore wind farms at sea.

Wind power is an alternative renewable energy source relied upon globally. From around 137 MW in 2000 to a little over 8.5 GW in 2014, Canada’s wind energy capacity increased significantly. Canadians near wind turbines are worried about the potential health impact of the noise and vibrations.

Both the motor and the wind itself generate noise when they travel through the blades of a wind turbine. Anyone who lives or works close to wind turbines has probably heard about the low-frequency noise they produce. These noises fall under the infrasound spectrum, which extends from 1 to 20 Hz.

Although most people cannot hear this kind of low-frequency sound, some may feel slight vibrations caused by it, especially when they are asleep. The specific wind turbine model can potentially affect this decibel level. But is it possible for these unheard sounds to still cause physical problems for us? Canada decided to engage in a long-term study to see if they could discover whether or not this belief held some truth.

Statistics Canada Official Title: Community Noise and Health Study, a large-scale epidemiological study was announced in July 2012 by Health Canada and Statistics Canada. The project was initiated to address community health concerns about wind turbines and to provide federal advisors with more comprehensive evidence.

There was no correlation (relationship, not cause-effect) between self-reported exposure to WTN (wind turbine noise) levels and a variety of medical diagnoses. We know it can have a detrimental effect on wildlife. The illnesses listed in humans included chronic pain, hypertension, diabetes, heart disease, vertigo, migraines, and various ear noises like ringing, buzzing, or whistling.

However, Canada is not the only country that has expressed concern about these types of sounds or noises. Portugal also investigated this area, but their focus was on power line poles and the sounds they may produce.

Portugal is the fourth-worst country in Europe for noise pollution, with 23.0% of the population affected. Because of the nature of their living environment and, most importantly, the low-frequency noise produced by power poles and lines, a larger proportion of an experimental group’s respondents reported health issues, such as cardiovascular disease, insomnia, and depression.

It may be that unchecked, infrared, and low-frequency noise (ILFN) can cause illness, physical and mental, since this noise also affects the immune system. Overexposure to ILFN causes a systemic condition known as vibroacoustic disease. Major issues including depression and mental dysfunction were observed in 3% to 5% of people exposed to LFN, which is higher than the overall population. An elevated heart rate and other possibly related issues were also noted after exposure to low-frequency sound. And serious health issues may manifest in people who are exposed to this noise regularly.

We are now approaching a new era in energy production and environmental issues that have never been tackled before, and more research is needed. We can neither dismiss nor blindly accept the paucity of research results on wind turbines, in particular, and other forms of energy that will come into use within the next decade.