Hearing Page

Specific Noise Environments

To understand noise and its effects on people, we need to understand specific noise environments. Depending upon the intensity of the sound, the length of time and how often over time the ear is exposed to it, noise affects our human condition in a number of ways from increased stress levels to permanent hearing loss. Excessive noise exists in our homes, in our workplaces and in our recreational pursuits.

Many environmental noise levels are unacceptable and on the increase. Rather than working to simply maintain noise levels and stop the increase of noise, efforts must be made to decrease noise both on and off the job.


Urban (City) Noise

"It's a jungle out there." Our urban environment is crowded, busy and noisy! Jackhammers pounding, sirens whining, alarms ringing, subway trains screeching, aircraft zooming overhead, car horns honking - these are but a few of the annoying and potentially hazardous sounds that city dwellers are almost constantly exposed to.

The noise problem has reached a point where the Organization for Economic Co-Operation and Development (OECD), which includes most of the world's industrialized countries, concluded that noise is now an important environmental problem.

"The hubbub of the city" - the phrase conveys the excitement, the hustle and bustle of urban life, the throng of crowds and traffic, traders, shoppers, rowdy diversion and entertainment. In ancient Rome, the clatter of iron wheels of wagons on the stone pavements disturbed the sleep and so annoyed citizens that legislation was enacted to control movement. Some cities of medieval Europe prohibited horse and carriage traffic to protect the sleep of the inhabitants. (World Health Organization, 2001)

Urban dwellers are besieged by noise, not only in the city's streets, but also in its busy workplaces and many noisy leisure activities. Tests conducted in the city of Toronto by The Canadian Hearing Society (CHS) in co-operation with The Toronto Star newspaper suggest that anyone working or living in the city is continually subjected to noise loud enough to be annoying and likely to cause long-term, irreversible hearing loss.

A Star reporter and CHS audiologist used a hand-held noise meter and wore computerized noise meters which registered all the sounds that they encountered during two days: the average sound level was almost 77 decibels. They also found sound levels of 100 decibels near construction equipment or when trucks drove by; 81 decibels in a downtown clothing store, the equivalent to noisy traffic; 89 decibels in a downtown pub; 97 decibels from car horns.

The World Health Organization proposes that "there is no identifiable risk of hearing damage in noise levels of less than 75 decibels" (for an exposure of 8 hours), but "for higher levels, there is an increasing predictable risk."

Airport Noise

Aircraft are a significant source of noise in urban environments, known to produce intense noise, vibration and rattle.

Complaints about aircraft noise continue to increase in number. Results of airport noise are interrupted sleep, disturbed rest and induced stress, which compromises the immune system and puts people at greater risk for all disease. This has been known for almost three quarters of a century when Smith and Laird (1930) noted stomach contractions when healthy people were exposed to noise. The health problems resulting from chronic airport noise, including higher blood pressure and boosted levels of stress hormones, may have lifelong effects.

Airport environments suffer habitat destruction, noise and other forms of pollution and residents experience increased health problems, interruption of sleep, lack of enjoyment of outdoor spaces and compromised learning environments.

Children in schools bombarded by frequent aircraft noise don't learn to read as well as children in quiet schools, Cornell University researchers (1997) have confirmed. And they have discovered one major reason: children don't tune in on speech in the racket. The study reports: "We've known for a long time that chronic noise is having a devastating effect on the academic performance of children in noisy homes and schools. This study shows that children don't tune out sound per se, rather they have difficulty acquiring speech recognition skills."

These researchers point to other health concerns related to chronic noise, including hearing damage, chronic cardiovascular activation, elevated annoyance and irritation, motivation problems such as learned helplessness and impaired cognitive development and reading achievement.

What is particularly alarming is the fact that our world is getting noisier.

Case Study: Combating Noise Pollution at Dorval Airport

Montreal's Dorval airport has taken steps to enhance the soundscape for neighboring communities. Such steps include the prohibition of loud aircraft from flying in or out of the area at restricted times of night. Pilots must observe strict take-off and landing procedures to reduce aircraft-induced noise. The airport's operating hours are among the most stringent in the world. Only smaller jets equipped with low noise engines and propeller-driven aircraft are allowed to land or take-off at any time of day or night. All other types of aircraft must comply with the restricted operating hours. How the runways work makes allowance for aircraft types, prevailing winds and relevant noise abatement measures designed to minimize aircraft-induced noise for citizens living in the immediate vicinity.

What You Can Do

Write to your local and provincial public representatives and ask them to fund studies on the effects of airport noise on health and to fund programs and standards to reduce the hazards of airport environment noise.

Train Noise

Similar problems exist with train noise. Although train noise affects fewer people than airport/aircraft noise, train noise is a growing concern.

Rural (Country) Noise

We all have images of the country as a place of peace and quiet, a place to get away from the noise and confusion of the city. But rural areas may not be as quiet as we imagine them, especially for the farming families who live and work there.

Farms are noisy places. On a daily basis, farmers are exposed to the loud sounds of such farm machinery as tractors, combines and grain dryers. Noisy power tools - a chain saw, for example - are common rural implements. Even some farm animals produce hazardous noise!

Many studies show evidence of farmers with noise-induced hearing loss. According to Dr. James Lankford, acting dean of the College of Professional Studies at the University of Northern Illinois, an alarming percentage of farmers have experienced some degree of permanent hearing loss as a result of prolonged exposure to loud noise. He bases these observations on hearing tests conducted at the annual farm Progress Shows throughout the American Corn Belt (Illinois, Indiana, Iowa) since 1988.

A total of 1,794 individuals have already taken part in the ongoing study. Noting that the results varied little from state to state and from year to year, Lankford states that "approximately 45 to 47 percent of the males tested had a significant hearing loss." He adds that although some percentage of this can be attributed to aging, the majority of the hearing loss was "undoubtedly due to noise exposure." A significantly smaller percentage of women participating in the study had experienced hearing loss.

Researchers from Northern Illinois University have reported that potentially damaging sound levels on the farm range from 85 to 110 decibels. For example, sound levels from tractors range from 89 to 98 decibels; grain dryer sound levels, at a distance of three feet from the dryer, range from 96 to 110 decibels and, at a distance of 20 feet, from 88 to 101 decibels.

Recreational hunting and shooting, common rural leisure activities, produce ear-splitting sound levels up to 170 decibels. Other noisy recreational activities in rural areas include such motor sports as stock car racing, tractor pulls and snowmobiling. (See booklet 3 Recreational Noise and Music.)

Protection

While noise-induced hearing loss cannot be reversed medically or surgically, its initial or further loss can be prevented.

• Farmers can wear commercially available ear protection such as earplugs or muffs in all noisy environments.
• Tractor mufflers and tractor cab seals should be in good working order to reduce the noise that reaches the farmer's ears. Most hearing loss related to tractor operation results from operating a model without a cab or with the cab door or windows open.
• Farmers, like industrial workers, should have annual hearing tests.

Household Noise

We may think of "home" as a quiet, peaceful haven from the noise and confusion of the city and crowded, noisy workplaces. But, even in our homes, we endure a barrage of annoying sounds: nearby traffic, a neighbour's barking dog, loud music from an adjoining townhouse. We add even more noise with our many household appliances: air conditioners, washing machines, coffee grinders, vacuum cleaners, food blenders, dishwashers, television sets, electric can openers, workshop power tools, hair dryers. At any one time, several of these noisy appliances might be filling a home with sound.

Outside, we care for our yards with a variety of noisy equipment: lawnmowers, hedge clippers, leaf and snow blowers, for example. Many of these noises are not loud enough to pose a hearing risk on their own, but they do add to the excessive noise that surrounds us on a daily basis. All this noise is not just a nuisance. It is yet another, unnecessary stressor in our lives. And it contributes to our total exposure to noise - noise that may be slowly, insidiously damaging our hearing.

Common Sound Levels of Household Appliances/Equipment

The following are sound levels measured for a variety of appliances at a distance of three feet:

Protection

• Ensure that you and any nearby children wear hearing protection when using lawn mowers, power tools, chain saws, leaf or snow blowers.
• Keep televisions and music down to a reasonable volume.
• Buy appliances that are not as noisy (check for lower decibel levels).
• Have your hearing checked every two years and see your doctor if you notice any hearing loss, dizziness or ringing in the ears. Do the same for your children.
• Avoid creating noise that will affect your community.

  For More Information chs.ca/info/noise/book4.html