Exposure to noise (i.e., unwanted or potentially hazardous sound) at home, at work, while traveling, and during leisure activities is a fact of life for all Americans. At times noise can be loud enough to damage hearing, and at lower levels it can disrupt normal living, affect sleep patterns, affect our ability to concentrate at work, interfere with outdoor recreational activities, and, in some cases, interfere with communications and even cause accidents. Clearly, exposure to excessive noise can affect our quality of life.
As the population of the United States and, indeed, the world increases and developing countries become more industrialized, problems of noise are likely to become more pervasive and lower the quality of life for everyone. Efforts to manage noise exposures, to design quieter buildings, products, equipment, and transportation vehicles, and to provide a regulatory environment that facilitates adequate, cost-effective, sustainable noise controls require our immediate attention. Specific recommendations that address these issues are included in this report.
This report looks at the most commonly identified sources of noise, how they are characterized, efforts that have been made to reduce noise emissions, and efforts to reduce the noise experienced by people in workplaces, schools, recreational environments, and residences. The report also reviews the standards and regulations that govern noise levels and the federal, state, and local agencies that regulate or should regulate noise for the benefit, safety, and wellness of society at large. This report also presents information on the cost-benefit trade-offs between efforts to mitigate noise and the improvements they achieve, information sources available to the public on the dimensions of noise problems and their mitigation, and the need to educate professionals who can deal with these issues.
Ubiquitous sources of noise include all modes of transportation—airplanes, trains, trucks, and automobiles; consumer products, such as lawnmowers, snow blowers, and leaf blowers; and manufacturing machinery in the workplace. Noise levels usually decrease as one moves away from a source, but people living close to the end of a runway or near a high-speed interstate highway cannot escape from highly annoying noise; lawn care equipment can annoy neighbors and at times can be hazardous to the user; and the requirements of operating noisy machinery can make it practically impossible for workers to retreat far enough to escape hazardous noise. Below are specific subjects addressed in this report.
IMPROVEMENT OF ENVIRONMENTAL NOISE METRICS
The committee looked in detail at the state of the technology with regard to noise metrics and concluded that modern advances in our ability to collect, store, and analyze noise data challenge us to reexamine current metrics that were developed in the 1970s or earlier with the objective of developing metrics better related to human response to noise.
HAZARDOUS NOISE AT WORK AND AT HOME
This report also provides information on noise, both occupational and nonoccupational, that can damage hearing. The committee recommends that current U.S. Department of Labor limits on occupational noise exposure be reviewed and changed. Engineering controls should be the primary means of controlling noise, and “buy quiet” programs will assist in the procurement of low-noise machinery and equipment.
TECHNOLOGIES FOR NOISE CONTROL
Technology alone will not solve all noise problems, but problems that are amenable to technical solutions can be solved by engineers with appropriate support from economists, psychologists, medical specialists, educators, and many departments in federal, state, and local governments. In this report the committee has made an assessment of transportation noise sources; noise from machinery, equipment, and consumer products that can affect U.S. competitiveness;
noise in the built environment; noise in the community; and hazardous noise. Some areas, such as aircraft noise reduction, have received a great deal of global attention, but other important sources of noise have received less attention, even though they affect many more people.
COST-BENEFIT ANALYSIS FOR NOISE MITIGATION
Cost-benefit analysis for different noise mitigation options is another area considered by the committee, both broadly and in the context of reducing noise generated by interactions between vehicle tires and road surfaces. At highway speeds this tire/road interaction noise dominates noise emissions from vehicles, and efforts are being made to design road surfaces that minimize this noise. The committee recommends that a formal analysis be performed to compare the costs and benefits of using pavement technology for noise reduction with the costs and benefits of installing noise barriers. This cost-benefit analysis would probably be a cooperative effort of the Federal Highway Administration, the Environmental Protection Agency (EPA), and several states. The efforts of the Federal Aviation Administration to develop a cost-benefit approach to analyze noise around airports could help in the development of a similar project to analyze options for reducing highway noise. European cost-benefit analyses, clearly much more extensive than similar American analyses, are also reviewed.
STANDARDS AND REGULATIONS FOR PRODUCT NOISE EMISSIONS
The European Union (EU) has been a leader in the development of noise regulations based on standards promulgated by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). These regulations are more extensive than regulations in the United States, and consequently European manufacturers have gained an advantage over their U.S. counterparts in meeting demands for low-noise machinery and other products worldwide.
Regulatory and standards-setting activities regarding noise, especially in the EU, are examined, and their impact on the ability of U.S. manufacturers to compete in world markets is assessed. EU member states have placed significant emphasis on the need for noise emission standards and have exercised waxing influence within the ISO, and to some extent the IEC, on the development of international noise emission standards. Meanwhile, U.S. influence within ISO and IEC on noise-related issues has waned. Building on voluntary standards, noise emissions from consumer products are much more highly regulated in Europe than in the United States, and European requirements on noise levels in the workplace also are more stringent than in the United States. The role of the U.S. Department of Commerce, especially its National Institute of Standards and Technology, is reviewed, and several recommendations are made for strengthening U.S. manufacturers’ participation in international standards-setting bodies related to noise control and for improving dissemination of information on noise emission requirements outside the United States.
Although noise requirements can sometimes be a burden, they can also encourage innovation. A manufacturer’s desire for the design of a low-noise machine for sale in world markets is a positive force that could lead to the introduction of quiet products into American markets and be an incentive for manufacturers and purchasers to cooperate in “buy-quiet” programs. Indeed, at the time of purchase, consumers rank noise as one of the top five characteristics when comparing product performance. Yet noise levels for U.S. products are often buried in product literature and reported in different noise metrics, making it difficult for consumers to compare noise levels at the time of purchase. Thus, consumers are unable to make informed decisions about the noise emission of a product. This problem could be corrected if product noise levels were prominently displayed and manufacturers adopted a system of self-enforcement.
American manufacturers have the ingenuity to design quiet products. However, manufacturers and trade associations, as well as the voluntary-standards community, have been unable to agree on a uniform standard for measuring and labeling product noise.
THE ROLE OF GOVERNMENT
In some areas—notably aircraft noise, occupational noise, and highway noise that can be reduced by barriers—government regulation has played a major role. But this report shows that improvements can be made in other ways as well. For example, authority for cost-benefit analysis, interagency projects, and dissemination of public information was granted to the EPA by Congress. Because of a lack of funding, however, EPA has been unable to carry out these activities. The study committee recommends changes that will make it easier for the federal government to improve the lives of Americans.
EDUCATION OF NOISE CONTROL ENGINEERS
This report also examines the state of noise control engineering education and concludes that the nation needs to educate specialists in the field and provide basic knowledge of the principles of noise control engineering to individuals trained as specialists in other engineering disciplines.
An informed public is an important element in efforts to create a quieter America, and the Internet is a low-cost avenue for dissemination of authoritative information on noise, noise control, and the effects of noise on people. The public would
benefit from knowing that there are engineering solutions to many noise problems, and a uniform system of labeling the noise emissions of products would enable the public to make informed purchase decisions. EPA has the authority to do more than it is currently doing to create and disseminate public information, and engineering societies can contribute information on noise reduction that is accessible to the public. Citizens groups can also be a source of public information on noise. Specific recommendations to enhance public information efforts are given in this report.
NOISE AND HEALTH
The general relationship between noise and health is not covered in this report, although new information is becoming available (Babisch, 2008; DEFRA, 2009). However, it will take a multidisciplinary study committee to evaluate these results and determine their relevance to the health of the American people.
Reducing the noise levels to which Americans are exposed will require cooperation among engineers, industrial management, and government in many disciplines, and it will not be accomplished in a short time. Nevertheless, reduced noise levels will contribute to improved quality of life for many Americans, and the committee believes that the recommendations in this report, if implemented, will improve the current noise climate.
Babisch, W. 2008. Road traffic noise and cardiovascular risk. Noise and Health 10(38):27–33. Available online at http://www.noiseandhealth.org/article.asp?issn=1463-1741;year=2008;volume=10;issue=38;spage=27;epage=33;aulast=Babisch;type=0.
DEFRA (Department for Environment Food and Rural Affairs). 2009. Estimating Dose-Response Relationships between Noise Exposure and Human Health in the UK. BEL Technical Report 2009-02. Available online at http://www.defra.gov.uk/environment/noise/igcb/healthreport.htm.