At homes or in offices, insulation of walls and double-glazing of windows can muffle sound from traffic, neighbors, and other sources from the outside world. Sound walls along highways can shield nearby neighborhoods from traffic noise. Individuals should protect themselves with earplugs or muffle ear protectors, particularly when noise levels exceed 85 decibels. In the industrialized nations, governments have laws and policies to counter noise pollution. In the united States, at least six federal agencies are involved in controlling noise pollution. Since 1969 the FAA has monitored and controlled noise from airplanes.
The agency requires that new aircraft meet specified noise standards and that old ones be retrofitted or retired. Local airport authorities, with FAA approval, reduce the impacts of noise pollution by routing flights over water or unpopulated areas on takeoff and landing, and by limiting traffic at night. The FAA also encourages airports and local governments to take steps on the ground, such as constructing sound barriers, insulating buildings, and restricting residential development in noisy areas. In extreme cases, airports have relocated people living under flight paths.
The Occupational Safety and Health Administration (OSHA) is charged with reducing noise in workplaces. Under OSHA regulations, no exposure above 115 decibels is permitted, exposure up to 115 decibels is limited to 15 minutes for an 8-hour shift, and average noise levels above 85 decibels are regulated. OSHA requires employers to measure noise levels, to muffle extremely noisy equipment, to provide ear-protection gear if necessary, and to offer regular hearing tests to workers who are regularly exposed to high sound levels. The Bureau of Mine Safety has comparable rules to protect miners.
The Department of Housing and Urban Development and the Veterans Administration require noise proofing in dwellings whose mortgages they finance. The Department Of Defense even has noise standards for certain military situations. In 1 972 Congress passed a Noise Control Act establishing an Office of Noise Abatement and Control in the Environmental Protection Agency. The office conducted research, coordinated the work of other agencies, and directly set noise standards for trucks, motorcycles, air compressors, truck-mounted airbag compactors, and railroads.
More standards would have followed, but in 1 981 Congress cut off funding for this effort. Some state and many local governments work to reduce noise pollution. State and local building codes include noise insulation requirements, and land-use planning is used to keep noise sources away from housing and offices. Local ordinances can ban the use of some equipment, such as leaf blowers, or limit use to certain times of day. In the last 30 years, the United States and other countries have expended considerable efforts to control noise pollution.
Most vehicles and many other noise producers are quieter than they used to be. On the other hand, there are more noise making machines than ever, operating more Of the time. In the United States, most of the rules governing nose pollution were established at least two decades ago, and critics are calling for new, stronger measures, as well as for better enforcement of the old ones. What is true of most other kinds of pollution is also true of noise: Our best efforts against it tend merely to keep matters from getting dramatically worse.