Noise Control: An Overview

The world around us is filled with sound. Every minute of every day we encounter an infinite variety of sounds, many of them rich with pleasant associations: the familiar chirping of crickets, the song of a bird, a child's laughter, the soothing patter of summer rain, or the rustle of leaves in a breeze.

We could not and would not live in a world of absolute quiet. In fact, sound is essential to our very survival. Our amazing sense of hearing has helped keep us alive since humans first moved across the land, where the snap of a twig or the growl of a predator warned of imminent danger.

However, while sound is a natural part of life, the ascendance of technology in our industrial society has spawned a great many unnatural and unnerving sounds, such as sirens and bells, horns and alarms; the roar of traffic, the deafening thunder of a jackhammer, or the disturbing whine and drone of garden equipment like lawnmowers and leafblowers. It is when these sounds interfere with the basic quality of our life, work, and play that we think of them as noise.

Tom Ogle, the director of Montgomery County's noise control program, indicates that noise is generally defined as unwanted sound, although he suggests that noise is more easily described as "the sound of someone else's stereo." And while noise is sometimes nothing more than a nuisance or a more personal, subjective judgement, there are circumstances where exposure to certain types and levels of noise can lead to physical or psychological damage, including permanent loss of hearing.

Ogle also points out that noise is one of the top ten issues used worldwide in determining the liveability of an urban area, and while not as dramatic as air or water pollution, noise pollution is one of the most important factors people consider in evaluating their basic quality of life, which is no doubt why we so frequently express a fundamental desire for "peace and quiet" in our lives.

The Problem with Noise

Sound is simple enough in its own way. Vibrations or waves of sound pressure fill the air, they travel from their source to our ear, which stimulates tiny cilia or receptors which in turn transmit impulses or signals to the brain. The brain then filters through the billions and billions of different signals it receives, interpreting and creating meaning out of the infinity of possible wave patterns.

There is a problem, however, when the sound we experience either exceeds certain defined levels of intensity, measured as decibels (dBA), or when the "noise" occurs at times or in places where it is unexpected and unwanted.

Using a sound-level meter, we find that whispering in an indoor location registers at approximately 20 dBA. The average office measures 50 dBA, with typical conservational speech ranging from 50 dBA to 70 dBA (65 dBA is typical of two people talking while three feet apart). As we move up this logarithmic scale, we discover a car horn measures 100 dBA at 10 feet, a hard rock band (indoors) registers at a deafening 120 dBA, and physical pain begins at 130 dBA, with a jet engine at 140 dBA. When continuous exposure to sound reaches an 85 dBA threshold -- as in a factory -- there is a great risk of permanent hearing loss.

However, beyond the danger of long-term exposure, there is also a cumulative effect when exposure to loud volumes is only incidental. Intense noise can damage the delicate cilia of the inner ear, making them unresponsive to future sensations. And since hearing loss is subtle, the individual continues to "enjoy" intense auditory distress, inevitably and permanently losing acuity at various frequencies. Studies have dramatically shown that many teenagers, through concert attendance and the use of headphones, have actually degraded their hearing ability to that of most 60-year-olds.

In this area, however, most painfully loud noises are easily avoided, and seldom intrude on our everyday life. For the most part, loud noise is associated with yard and garden equipment, stereos, barking dogs, construction, and traffic. In fact, transportation is the greatest single source of ambient noise, with peak-hour levels along major roadways at 72-74 dBA (at 50 feet), with the Beltway peaking at 80 dBA.

The problem with noise often has a great deal to do with time of day. Reasonable noise levels during daylight hours are often unacceptable at night, especially when they interfere with sleep or relaxation. And since neighbors are not always "neighborly" regarding their personal noise generation, some outside regulations and ordinances are generally required.

Noise Control Ordinance

Because noise can and does have a significant impact on public health, the U.S. Environmental Protection Agency launched the Noise Control Act in 1972 to foster the development of state noise control programs through technical assistance grants and guidance documents. Regrettably, while these regulatory initiatives spurred the development of state programs nationwide, including an ambitious program in Maryland, they were virtually eliminated when the Reagan administration zeroed-out funding in 1981.

Fortunately, EPA's leadership lead Montgomery County to develop a substantial noise control ordinance, first passed in 1975, which remained in effect even as the state abandoned its programs in 1981. Today, the County has perhaps the only viable and enforceable noise control ordinance in the nation, which includes civil fines of $500 for first-time violations, along with the possibility of criminal penalties.

The Noise Control Ordinance, which was amended in 1986, establishes environmental guidelines for individuals and businesses, including an important "quiet hours" provision, to ensure that communities will be protected against loud noise from 9:00 p.m. to 7:00 a.m. on weekdays, and from 9:00 p.m. to 9:00 a.m. on weekends and federal holidays. The ordinance prohibits noises louder than 55 dBA across a residential property line.

Daytime standards naturally allow for a higher level of activity, though not to exceed 65 dBA at the property line. Also, a 75-85 dBA exemption is made for construction activities, although additional revisions passed in December 1996 now restrict any noise above 65 dBA on weekends.

Other revisions expand the noise ordinance beyond objective or technical standards (those measured by noise meters), and now allow for the subjective enforcement of noise disturbances or "nuisances," which has become a tool for the police to help maintain peace and quiet in our communities.

New Challenges

It is important to realize that even with a responsible Noise Control Ordinance in place, our community and our world is changing. Smart Growth incentives, land use planning and zoning are clustering development wherever possible, concentrating population into multiple-use areas. Traditional residential areas now share space with a variety of commercial uses. And businesses, such as offices, restaurants, and hotels, are fast learning that noise control is good business -- and good for business.

Furthermore, our demographics are changing. An increasing number of individuals are running consulting firms from their homes or telecommuting; individual work schedules are changing with flex time and other incentives; and a growing number of people are working and sleeping at totally different times.

All of these zoning and "behavior" changes are creating new considerations for noise control. Having a lawn service mow grass or blow leaves might have been acceptable during a midweek afternoon, but that activity now has the potential to interrupt an at-home teleconference or otherwise disturb a home office environment.

The solution, again, may be revisions to the County's Noise Control Ordinance. New guidelines, waiver provisions, and temporary exemptions will need to be developed, with all of these changes attempting to balance equities: the needs and expectations of a diverse and rapidly changing community.

Sounding-off: What You Can Do

You can play a part in framing changes to the Noise Control Ordinance by sending comments, opinions, and observations to the Montgomery County Noise Control Advisory Board (NCAB). Anecdotal information is needed to help reflect your experiences and expectations as a resident or home-office worker. Regulations pertaining to power garden equipment, home auto repair, and other equipment and activities will need to be amended, but only you can truly provide the feedback the Advisory Board needs to consider in weighing proposed revisions.

Questions or suggestions should be sent to the Department of Environmental Protection, 255 Rockville Pike, Suite 120, Rockville, Maryland 20850. Questions or requests for a noise control information kit, including a copy of the current ordinance, can be obtained by calling 240.777.7770.

Additional Help:

Animal Noise Disturbances: 301.279.1823

Trash Collection Noise (during quiet hours): 240.777-6410

Noise Disturbances/Violations: 240.777.7770