Cairo - From blaring car horns to wedding parties, rising noise pollution in the 24-hour metropolis of Cairo has reached alarming levels, leading to hearing problems, irritability and even death.
Living in the city centre, where noise levels reach an average of 90 decibels (dB) and never drop below 70 dB, is like spending all day inside a factory, a 2007 study by the Egyptian National Research Centre (NRC) said.
"What's striking about Cairo is that noise levels on different streets at different times of day are well over limits set by the environmental protection agency (EPA)," the NRC's Mustafa Ali Shafiye said.
"In downtown, noise levels may attain 90 dB at 7:30 am, bearing in mind that the normally acceptable level set by the EPA is 35-55 dB," he told AFP.
In December, the respected New Scientist magazine said that "noise kills in much the same way as chronic stress does".
It causes "an accumulation of stress hormones, inflammation and changes in body chemistry that eventually lead to problems such as impaired blood circulation and heart attacks."
According to Dr Mohammed el-Shazly, an ear specialist at Cairo University, "the noise in Cairo is exceptional - it cannot be compared to any other Arab city.
"What is special about Cairo is that industrial zones and residential areas are not separated. People like policemen who are permanently on the street can be severely affected."
People start to lose their hearing gradually, he said, and once that happens the only cure is to get a hearing aid.
"Car horns, loud music, shouting, ageing engines and the occasional party can lead to a series of health problems including hypertension, hearing loss, cardiovascular effects and general irritability" said Nagat Amer, an environmental health specialist at the NRC.
"Noise severely affects pregnant women who are permanently exposed to it. It causes retraction in blood vessels and they give birth to small babies," she added.
"The cost of this is enormous - we can count non-concentration at work, absenteeism, accidents, handicaps," she said. "Protecting ourselves from noise is much less expensive than what it may cost later."
According to the World Health Organisation, which considers noise pollution to be the world's third worst after polluted air and water, exposure for more than eight hours a day to sound in excess of 85 db is potentially hazardous.
The ministries of health and environment are planning to establish a national network for monitoring noise levels in Egypt, but no date has yet been fixed for it to begin gathering data.
A 1994 law laying down legal ambient noise limits is largely ignored. Under this law, levels should not exceed 52 db during the day, 37 db at night and a very loud 90 db in industrial areas such as factories.
With Cairo's population continually expanding and no official solution within earshot, tens of thousands of people are fleeing to quieter and less-polluted suburbs in the desert.
"I used to hear car horns, shops opening and closing, people shouting, the doorman talking loudly," said Dina Kozman, a housewife who left the city centre three years ago for a residential compound 20km away.
"You feel like you know the life of everyone while you are in bed. We don't want to have this stressful lifestyle with noise and traffic. Traffic makes noise and noise makes stress... it's a vicious circle."