by Lawrence S. Finegold, Soames Job, Ronald de Jong, and Barbara Griefahn
The 8th International Congress on Noise as a Public Health Problem, held last summer in The Netherlands, offered a valuable summary of research conducted over the past five years by nine international "noise teams" on the effects of noise exposure on humans and other animals. Participants also previewed research priorities for the next meeting in 2008, when the 9th International Congress which is co-sponsored by ASHA will convene in the United States for the first time in 40 years. ASHA member Jerry Tobias will serve as president of the 2008 event.
The International Commission on Biological Effects of Noise (ICBEN) organizes each congress and develops the noise teams. Together the teams cover all of the major effects of noise exposure on humans and animals. At the 2003 Rotterdam conference, 120 papers were presented. The broad significance of the research was underscored by the involvement of the World Health Organization (WHO).
The ICBEN's nine International Noise Teams and their responsibilities include: Team 1, work on noise-induced hearing loss; Team 2, noise and communication; Team 3, non-auditory physiological effects induced by noise; Team 4, influence of noise on performance and behavior; Team 5, effects of noise on sleep; Team 6, community response to noise; Team 7, noise and animals; Team 8, effects of combined agents (currently inactive); and Team 9, regulations and standards.
Reports of the first four noise teams were included in Part One (see the Oct. 5, 2004, issue of The ASHA Leader). Following are reports from other noise teams at the congress.
Effects of Noise on Sleep
Sixteen papers were presented on sleep-disturbance research and policy-related issues. Residents living near airports, railway tracks, busy roads, or other noise-emitting facilities evaluate sleep disturbance as the most deleterious effect of noise. The data suggest that these noises might affect mood, well-being, and performance the next day. Sleep disturbances are suspected to contribute eventually to the genesis of chronic health disorders. Most reviewers agree that the effects on sleep depend on the physical characteristics of the noises as well as on individual and situational factors. Also indisputable is the significance of personal features such as age, personal traits, and biorhythm alterations.
One workshop addressed sleep disturbance and its usefulness in developing nighttime noise policies. Of particular interest was discussion of new large-scale aircraft sleep disturbance studies around Schiphol Airport in the Netherlands. Relations were measured between aircraft noise-induced increase in motility (restlessness) as measured by an actimeter, and indoor sound levels of aircraft noise events. Actimetry recordings covered 63,242 events. Age, time after sleep onset, clock time, and indoor equivalent aircraft sound level were among the variables found to modify the exposure/response relations. Noise studies also are underway at the Cologne/Bonn Airport in Germany.
In the United States, Finegold conducted a meta-analysis of previously published major sleep disturbance field studies. The result is a sleep disturbance prediction curve potentially useful in developing policies on nighttime aircraft noise exposure. Karl Pearsons described the initiation of another ambitious research program in the U.S. based on a 2003 National Sleep Disorders Research Plan. The plan, sponsored by the U.S. Department of Health and Human Services and the National Institutes of Health, will address a wide variety of environmental stimuli, including noise, vibration, light, temperature, and humidity.
Community Response to Noise
The congress featured 22 papers on community response to environmental noise and a six-paper session on aircraft noise. The links between community noise research and noise policy development are growing. One potentially important approach is the concept of "soundscapes" to describe existing community-wide acoustic environments and to capture community values and preferences.
The development of new noise exposure criteria has been the focus of much work in the past five years. The most significant recommendations were the criteria that appeared in the WHO's "Guidelines for Community Noise" (2000).
Research presented at the conference noted that important negative effects of noise, such as community annoyance, occur at levels below the criteria recommended by WHO. More work needs to be done on effects that occur at less than 55dB LAeq(16). As communities attempt to reach the WHO criteria, the Environmental Impact Analysis Process (EIAP) provides a methodology for making noise decisions at the individual project level and has been used successfully in many countries for decades. Finegold presented a paper on how traditional EIAP concepts can be updated and expanded to provide a mechanism for obtaining public input to the decision-making process, for making noise mitigation choices, and for resolving disputes between noise producers and the community. An interesting paper by Frank van den Berg of The Netherlands also addressed a concept very similar to EIAP. Overall, a wide range of excellent topics regarding community responses to noise was covered and many new ideas are evolving (Fields, et al., 2001).
Noise and Animals
Compared to noise studies on humans, studies on animals have barely scratched the surface. However, considerable progress has been made in this area. In the past decade, researchers have taken care to describe the noise stimuli and to ensure that experiments are repeatable.
Progress has been made in the last few years in understanding the effects of noise on birds and marine mammals. Studies focusing on fish and on terrestrial and aquatic reptiles, however, are only beginning. Also, noise-exposure standards for one species do not necessarily apply to other species. Assessing noise effects needs to take into account not only the species' hearing ability, but also the ability to escape the sound. Further consideration must be given to the biological costs of avoiding sounds and to habituation to noise.
Specific animal groups that have been receiving attention in recent research include: terrestrial animals, including birds (the most studied animal), mammals, and reptiles; and aquatic animals, including marine mammals, fish, and reptiles. The types of animals being studied has markedly increased over the last five years. Bird studies included woodpeckers, owls, falcons, and various species of meadow birds. Marine animals included whales, dolphins, sea turtles, fish, and seals.
Recommendations for a future research agenda include continuing to develop hearing threshold curves for groups of animals, dose/ response curves for groups of animals, and use of specific weightings rather than A or C weightings. The team also recommended developing research to understand the function of habituation in relation to noise effects.
Policy Issues
Rapid growth has occurred in efforts to develop adequate noise policies in the European Union (EU) since the last congress. The European Commission implemented a large number of noise-source-emission directives and recently announced promulgation of the Environmental Noise Directive. To complement this legislation, a number of large-scale, collaborative research programs have been launched. The most urgent need for a new noise exposure policy, especially in the EU, is for an aircraft-noise/sleep-disturbance prediction curve that represents a consensus of the international scientific community. The sleep-disturbance workshop held at the congress was part of the ongoing efforts to develop this consensus. The WHO is also active in efforts to reach agreement on sleep-disturbance issues.
For presenters and observers, the five-year interval between these international meetings permits a broad look at recent research work, industrial applications, and government regulations. Accordingly, the meeting helps to determine the focus of future research and to stimulate cooperative activities.
Since many of the world's major noise-effects researchers attend these congresses, networking and collaboration among a broad base of colleagues facilitates the development of new ideas and approaches.
Lawrence S. Finegold is the principal of Finegold & Co., Consultants, Centerville, OH. Contact him at LSFinegold@earthlink.net.
Soames Job, ICBEN chair from 2003-2008, is in the department of psychology at the University of Sydney in Australia.
Ronald de Jong, president of the 2003 Congress, is an official at the DCMR Environmental Agency Rijnmond Schiedam, the Netherlands.
Barbara Griefahn, the ICBEN chair from 1998 to 2003, is at the institute for occupational physiology at Dortmund University, in Dortmund, Germany.