A noise barrier is an exterior structure designed to protect inhabitants of sensitive land use areas from noise pollution. Noise barriers are the most effective method of mitigating roadway, railway, and industrial noise sources –
other than cessation of the source activity or use of source controls.
The sound tube in Melbourne, Australia, designed to reduce roadway noise without detracting from the area's aesthetics.
Acoustical scientist measures sound in noise barrier design study, Santa Clara County, California.
Noise barrier earth berm along California State Route 12, Sonoma County, California
Noise abatement walls often block rail passengers' or road users' view and attract graffiti.
Noise pollution, or sound pollution, is the propagation of noise or sound with ranging impacts on the activity of human or animal life, most of which are harmful to a degree. The source of outdoor noise worldwide is mainly caused by machines, transport and propagation systems. Poor urban planning may give rise to noise disintegration or pollution, side-by-side industrial and residential buildings can result in noise pollution in the residential areas. Some of the main sources of noise in residential areas include loud music, transportation, lawn care maintenance, construction, electrical generators, wind turbines, explosions and people.
A Qantas Boeing 747-400 passes close to houses shortly before landing at London Heathrow Airport.
Traffic is the main source of noise pollution in cities like São Paulo, shown here.
Measuring the noise level from a leaf blower using the NIOSH Sound Level Meter app
The CityLink sound tube in Flemington, Melbourne, Australia, is designed to reduce roadway noise without detracting from the area's aesthetics.