Noise assessment inside the Greater Cairo Underground second-line Metro
Underground metro trains, which connect different terminals of big crowded cities, are the best means of public transportation. The metro is environmentally friendly because the trains are electrically driven and so do not emit chemical air-pollutants. The number of people using the Greater Cairo Underground Metro approaches two million per day, beside about one thousand workers in the different activities related to the metro. Metro users and workers complain about the high noise levels emitted by metro units travelling in the tunnels, especially at the turns, the entrance of tunnels and at stations while braking.
Exposure to high noise levels for a long time causes many health hazards: either auditory, such as temporary and permanent hearing loss, or extra-auditory such as effects on the cardiovascular system, blood pressure, heart and respiratory rates, central nervous system. Noise also leads to stress problems such as lack of concentration, leading to accidents. Noise has adverse effects on psychological, biological, immunological and hormonal systems of the body.
Due to the above mentioned reasons, suggestion has been made to start this research to assess and diagnose these problems, and to find the proper methods for early detection and proper management of these health hazards; in addition to the engineering solutions for the noise problem. Measurements of noise levels have been made inside the units while travelling and outside the units at the stations platforms to evaluate the noise problem and to suggest some kind of solutions to the problem. The calculations of different noise indices have been made and compared with international criteria and national laws. The comparison shows that the noise levels are clearly unacceptable, for indicesL1,L99, and LNP, both inside the metro units and outside the units at station platforms along the passage.