Iranian Association of Environmental Health (IAEH)
Abstract
Noise pollution is a major problem for the quality of life in urban
areas. The present study was conducted to determine the noise levels of
road traffic at central area of Tehran. It focused on one of the busy
and crowded square along with its 7 connecting streets, which had a
heavy traffic and located in the downtown of the city. Total of 115
measuring points were selected along the roads, pavements and in the
shopping areas to adequately represent the different acoustically
commercial situations. The measuring points were divided in to 4
site-groups namely; Street, Pavement, Shop and Barrier each with 60,
40, 10, and 5 measuring points respectively. The measurements were
carried out during a full week days started on Saturday morning and end
on Friday evening. The A-weighted continuous equivalent sound level
values, LAeq; LA max; LA min ; and the statistical levels: L1, L10,
L50, L90 and L99 as well as the octave band center frequencies sound
pressure levels were manually measured at each point separately. The
mean values of LAeq for Street, Pavement, Shop and Barrier site groups
were 78.5, 73.3, 68.7 and 70.8 dBA respectively and the overall mean of
LAeq was 74.7 dBA. The statistical test (p<0.01) showed that the
mean values for LAeq in all site groups as well as the overall mean
value were higher than 65 dBA, which is the daytime governmentally
prescribed noise limit for commercial areas. Comparing the individual
measurements has also shown the 86.6% exceeded values from 65 dBA. The
highest mean noise level in center frequencies upper than 1000 Hz was
71.5 dBA which was observed in the Street site group and the lowest one
was 43.2 dBA in the Shop site group at 8000Hz center frequency. The
corresponding values for the center frequencies lower than 1000 Hz were
78.2 and 66.1dBA at 63 and 500 Hz which were also observed in the
Street and Shop site groups respectively. It can be concluded that the
downtown of the city is environmentally noise polluted and the road
traffic is the major source of it. Noting the noise emission standards,
police control, and promoting the citizens awareness about the high
level noise risk may help to relieve the noise problems in the city