Interested in this kind of news? Receive them directly in your inbox. Delivered once a week. Sign Up Awareness of the problem of noise has grown in recent years, as techniques to measure its impact on heart disease, brain function (including learning, especially for children), sleep disturbance have improved. The EEA’s study says the harmful effects of noise ‘arise mainly from the stress reaction it causes in the human body, which can also occur during sleep’. In its briefing Managing Exposure to noise in Europe, the EEA argues that the healthy limit for daytime noise is 55 decibels (dbA), with noise above 50 decibels at night liable to disturb sleep. A level of 55 decibels is equivalent to light traffic. It says around 100 million people in Europe are affected by noise levels above 55 caused by road traffic, while 32 million are exposed to traffic noise above 65 decibels. Road traffic is the biggest source of noise above acceptable levels, with rail second (19 million Europeans are exposed to levels above the limit), and 4.1 million living near airports suffering from unacceptable levels of aircraft noise. By contrast, just 1 million are exposed to unacceptable industrial noise within urban areas. The worst affected capitals are Sofia, Bucharest and Tallinn, while Stockholm, Berlin, London and Paris are the least affected. The World Health Organisation ranks noise as the second most harmful environmental stressor after air pollution.