Excessive noise levels in Cairo are increasing stress-related illnesses and hearing impairments among the Egyptian capital’s 15 million residents, according to a study conducted by the Egyptian National Research Centre.

Noise levels in Cairo regularly reach an average of 90 decibels during the day – the equivalent sound level of a diesel truck – and seldom drop below 70 decibels, despite the introduction of a law in 1994 that set the maximum allowable daytime noise level at 52 decibels and 37 decibels at night.

Normally acceptable levels, according to the US Environmental Protection Agency, are considered to be 35–55 decibels. Noise levels are higher in Cairo than in many other cities because industrial and residential areas aren’t divided, according to an ear specialist from Cairo University.
 
The World Health Organization (WHO) claims that continuous exposure to high levels of noise interferes with social behaviour, metabolism and breathing. A recent WHO report estimated that chronic and excessive traffic noise is implicated in the deaths of three per cent of Europeans suffering from ischaemic heart disease. Worldwide, seven million people die from heart disease every year and, assuming an average exposure to traffic, that would put the annual toll from exposure to noise at 210,000 deaths.