Environmental noise is among the "top environmental risks to health," according to the WHO report.
More than 100 million Europeans are affected by road traffic noise alone each year. "Noise continues to be a concern," noted Dr. Dorota Jarosińska, program manager for living and working environments at the WHO regional office for Europe.
The new guidelines are "an important update," given the evidence and links to health problems, said Stephen Stansfeld, professor at Barts and Queen Mary University of London and chair of the Guideline Development Group, an independent organization that advised WHO on the guidelines.
Excessive noise can affect blood pressure, hypertension and heart disease, which can lead to heart attacks and mortality from cardiovascular disease. Children's cognition and health are also affected.
Jonathan Gale, a professor of cell biology and director of the UCL Ear Institute, wrote in an email that he "welcomes the new WHO guidelines as they bring the human impact of noise exposure to the fore."
This report, the first since 1999 to address noise levels, included considerations on new noise sources such as wind turbine and "leisure noise," which includes music at nightclubs, pubs, fitness classes, live sporting events and concerts and through personal listening devices.
Two independent expert groups in the field of environmental noise reviewed recent research and helped develop the guidelines about acceptable 24-hour and nighttime noise levels.
The new recommendations suggested reducing average noise levels of road traffic below 53 decibels, the equivalent
of hearing a dishwasher in the next room. At night, 45 dB of road traffic noise was recommended. WHO said 40% of European Union residents are exposed to traffic noise levels exceeding 55 dB
Stephen Turner, president-elect of the Institute of Acoustics in the UK, believes that this reduction "can be achieved."
"The challenge is, there are an awful lot of people affected. Whether we have the technology yet to be able to secure that reduction without having an adverse impact on travel and connectivity, I'm not sure," he added.
For railways, aircraft and wind turbine noise, an average level of 44 dB to 54 dB was recommended, depending on the source. Noise from aircraft at night is suggested to be limited to less than 40dB, as higher levels of aircraft noise are associated with adverse effects on sleeping.
Leisure noise -- which is usually desired -- was recommended to be kept at an average of 70 dB. Damages to hearing outcomes can be tied to the source, and therefore we have a higher tolerance for desired noises.
WHO published guidelines on community noise in 1999 and night noise in 2009. In 2010, the member states of the European region requested guidelines including leisure and wind turbine noise.
Noise pollution is very diverse. Each source has different characteristics of loudness and consistency, according to the report. The health effects of each type of noise pollution therefore vary. But the new guidelines are based on reviewed evidence that noise exposure has risks of negative health outcomes. "The most frequent impacts are annoyance and sleep disturbance," Stansfeld said.
Gale noted, "Exposure to environmental noise can result in hearing loss that, in the longer term, can cause social isolation and [an] impact on health and well-being. Both the level and duration of the exposure are important factors.
"However we know much less about the effects of exposure to low levels of environmental noise over long periods," he added. "We think such noise is unlikely to affect our sensory hair cells [in our ears] but may well effect our brain processes and possibly our mental health."
Children were particularly affected by airplane noise, with evidence showing effects on reading comprehension and development of metabolic syndromes, such as obesity and diabetes. These effects can be aided from the chronic stress of being exposed to traffic noise.
Turner noted that the health effects, such as increased risk of heart attacks, manifest at "high exposure" of noise levels. "If we focus on reducing the high exposure [of noise pollution], we can reduce those adverse health risks."