Another new study, led by the London School of Hygiene and Tropical Medicine, suggests that traffic noise has an impact on human health.
The researchers modelled annual noise from 2003 to 2010 along around 63,000 roads in the Greater London area. They split the noise into daytime noise (7:00-23:00) and night-time noise, and categorised it as being below or above 55 decibels, a health threshold established by the WHO.
They also gathered data on hospital visits for cardiovascular reasons, heart disease and stroke, as well as deaths falling under these categories, and collected measures of poverty, smoking and air pollution.
The researchers found that road noise had a measurable impact on the health of Londoners. Adults in areas where the daytime traffic noise exceeded 60 decibels were more likely to be admitted to a hospital for stroke, compared with areas where noise didn’t reach 55 decibels. Among the elderly (those over 75 years of age), daytime road noise was also associated with hospital admissions related to cardiovascular disease, and night-time noise was related to stroke admissions. In all London adults, daytime road noise was associated with an increase in all mortality causes in areas over 60 decibels, compared with places under 55.
In line with previous studies, the researchers suggested that sounds from the environment might increase heart rate, blood pressure and stress, with these impacts having a cumulative effect on health over time. The role of noise in high blood pressure, in particular, might explain the high risk of stroke in those living in the loudest areas.