Like second-hand smoke, second-hand noise is a pollutant imposed on us against our consent, and at times, places, and volumes over which we have no control. Environmental noise pollution is a threat to health and well-being, and long-term exposure can cause hearing impairment, disrupted sleep, impaired task performance, negative social behavior and annoyance reactions, disturbances in mental health, and cardiovascular disturbances. The World Health Organization (WHO) estimates that one million healthy life years were lost every year from traffic-related noise in the western part of Europe in 2010. 

In London alone, more than 1.6 million people are exposed to road traffic noise levels during the day above 55 dB, the level defined by the WHO as causing health problems (the volume of a dishwasher). With the planned expansion of the 3rd runway at Heathrow, an additional 2.2-3 million Londoners would be at risk of severe exposure. 

Reducing noise may provide a significant benefit towards reducing the health related costs of road traffic noise in a community. But how will we deal with sustained growth in highway, rail, and air traffic? Do we find remedies for noise, or stop it at its source?