当前世界环境

The most common environmental concern in metropolitan cities worldwide is noise pollution. Kota metropolis (India) is also suffering from the problem of the increased noise level in the urban environment. Kota metropolis has been selected for the assessment of noise pollution. The main reasons behind the increasing level of noise in the city are increased population, rapid urbanization and industrialization, increased transportation facilities, urban development, construction and demolition works etc. The noise levels were recorded for day-time (6 am to 10 pm) as per Indian standard time for 96 days. Sixteen sampling points are made within the city depending upon the category of area/zone such as industrial, residential, silence and commercial. Six days were prescribed for each sampling location for noise level measurement. Noise descriptors such as L_max, L_min, L₁₀, L₅₀, L₉₀, NC (noise climate), L_np(noise pollution level), L_eq(equivalent noise level), and NEI (noise exposure index) were computed with the observed data. Noise descriptors are very useful to indicate the physiological and psychological effects of noise pollution associated with noise levels. It makes regulating agency to take necessary actions in high noise areas for noise vulnerable groups such as Childs, old persons etc. Noise levels were recorded with the digital sound level meter " HTC SL-1350". Obtained equivalent noise levels were in between 65 dB(A) to 85 dB(A). The results were then compared with the WHO standards of community noise levels, and Indian noise pollution standards. It is noticed that the noise levels in all monitoring stations were well above the limits of the standards prescribed by the WHO and CPCB. Small variations in noise levels were observed for all sampling locations i.e. noise levels were almost similar at sampling locations. Noise levels were distinct in magnitude for morning and evenings hours. Noise Exposure Index (NEI) was greater than 1 which shows significant high noise levels in all the sampling locations. Kota metropolis desperately needs new strategies to reduces the high noise level in the city. Regulating agencies should take necessary action before things get out of control. Some immediate actions are suggested in the study.