Spatio-temporal patterns of road traffic noise pollution in Karachi, Pakistan.

We studied the spatial and temporal patterns of noise exposure due to road traffic in Karachi City, Pakistan, and found that levels of noise were generally higher during mornings and evenings because of the commuting pattern of Karachi residents. This study found the average value of noise levels to be over 66 dB, which could cause serious annoyance according to the World Health Organization (WHO) outdoor noise guidelines. Maximum peak noise was over 101 dB, which is close to 110 dB, the level that can cause possible hearing impairment according to the WHO guidelines. We found that noise pollution is not an environmental problem reserved for developed countries, but occurs in developing countries as well. For this reason, steps might be required to reduce noise levels caused by road traffic.