Community Noise Management

 

The Noise Control Act of 1972 (NCA) established by mandate a national policy "to promote an environment for all Americans free from noise that jeopardizes their public health and welfare". The NCA provides for a division of powers between the Federal government and State and local governments. The primary Federal responsibility is for noise source emission control. The States and other political subdivisions have the responsibility to control the use of noise sources and the levels of noise to be permitted in their environment. The exceptions are transportation noise sources including aircraft and railroad operations and motor vehicle traffic involved in interstate transport.

 

The concept of making individual states and communities responsible for noise management is a fair one. It relies on three basic premises. First, noise is a temporary impact; the impact ceases when the noise source does. Second, noise is a local impact; the impacts rarely extend great distances from the noise source. Third, there is an inherent cost associated with reducing noise, including the financial costs involved in noise reduction and the costs associated with legislative restrictions. Managing community noise is a balancing act and often one that involves higher costs and greater restrictions for increased noise control. Therefore, a common belief is that the local communities should decide what the appropriate level of noise management (including regulation) should be within their community.

 

Noting these three premises, one can realize why transportation sources are exempt from local control. Transportation sources are often frequent enough to be considered continuous and their mobile nature results in distributing noise impacts across the nation. The Federal control over transportation sources maintains a uniform control over the sources as they travel from state to state.  Federal control also does not impede transportation between states and communities through changing noise control regulations that might restrict vehicle uses. 

 

Unfortunately, transportation noise sources are typically a community’s most prevalent and predominant noise sources. The States and their political subdivisions subsequently only have the responsibility to control the stationary noise sources within their communities and those mobile sources that are not directly involved with interstate transport. Nevertheless, this level of control also involves the balancing act between higher costs and greater restrictions for increased noise management.

 

Since community-based environmental noise regulations do not exist on the federal level; State and municipal regulations are the primary means for communities to manage noise. What is notable is that very few states have addressed noise issues with legislation or have established a framework that can provide effective community noise management. If State regulations for community noise management do not exist, the municipalities have the choice and responsibility to manage noise issues.

 

Community based environmental noise management follows two general approaches:

  (1)  Decibel-based noise criteria that restrict sound emission; and

  (2)  Subjective "public nuisance/disturbance” noise standards which do not require the use of sound level meters for enforcement.

 

Decibel-based noise criteria offer two substantial benefits; they can apply to both proposed and existing facilities, and they provide a definitive scale to enforce noise violations. Communities have the ability to prevent excessive noise exposures from occurring during permitting by providing a fixed limit that developers can use as a design standard. Communities also have a definitive means to address noise complaints and enforce compliance at existing facilities.

 

Decibel based standards offer fixed impact thresholds, but can be the most difficult to enforce from a practical standpoint. The enforcement difficulty is the focus on decibel readings. In order to enforce the fixed impact thresholds, measurements have to be made with sophisticated instrumentation following an established measurement protocol. Municipal enforcement can be an issue since complex instrumentation and trained personnel are necessary. The decibel based standards offer the benefit of being much less subjective than nuisance criteria and are therefore well suited for design standards and are less likely to experience legal challenges of interpretation.

 

Nuisance noise ordinances provide some general protection to the community from environmental noise impacts. One inherent problem with nuisance ordinances is that they are vague and may be difficult to apply consistently and enforce when they are challenged. Public nuisance noise ordinances are typically based on subjective standards. A common definition is a noise condition that is objectionable to one or more reasonable persons. Nuisance criteria are easier for non-acoustically trained personnel to enforce; however, subjective criteria may be challenged in court. Enforcement can often be made through citizen witnesses without the need for rigorous measurements. Communities without specific nuisance noise policies may not be able to adequately establish a nuisance condition and thereby regulate community noise.

 

The greatest benefit of nuisance ordinances is they offer flexibility in noise management. The subjective nature of nuisance criteria includes the inherent flexibility in annoyance perception. Noise can therefore be tolerated in areas that are not sensitive and regulated in areas that are. Noise management can also evolve more easily with the community’s needs and desires.

 

Some states and communities that do not have specific noise management policies have promulgated legislation that requires noise issues to be addressed during an environmental permitting process, particularly for large site developments. In these cases, environmental review typically occurs on the state or regional level and may incorporate land use planning and community zoning. When noise issues are identified during the permitting process, noise abatement can be incorporated in the environmental permits and later enforced through permit compliance conditions. However, through this process, existing facilities and projects that do not exceed the large site development thresholds do not receive any environmental review with respect to noise.

 

 

Audibility and Annoyance

 

It is very important to note that it is not reasonable to use the “threshold of audibility” as an impact determinate at residential locations with low or moderate noise exposures. The human ear is a very good hearing device and can distinguish and locate sounds with 10 to 100 (10-20 dB) times less energy than the average ambient sound during quiet times. Noise, by definition, is considered unwanted sound, which is a subjective interpretation of a sound. The “threshold of audibility” is important because it reflects when a person becomes aware of the sound and its cause which triggers annoyance. The sound level is not high enough to create an adverse impact or annoyance in a reasonable person but the association with the noise producing activity is the trigger for annoyance. A good analogy would be the noise generated by a mosquito; the sound level could hardly be considered a noise impact but the sound represents the presence of a potential parasite and therefore triggers a high level of annoyance.

 

 

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