Appraisal and mapping the spatial-temporal distribution of urban road traffic noise

The present study aims to compute the temporal and spatial distribution of road traffic induced noise pollution in an urban environment by monitoring and mapping. The study area was the entire Asansol city of West Bengal, India. A total of 35 locations were selected for collection of data, classified as industrial, commercial, residential, sensitive and mixed areas according to the national regulatory standards. Noise recordings were conducted during morning and night hours. Day time Leq level ranged between 51.2 and 89.0 dB[A], whereas it ranged between 43.5 and 81.9 dB[A] during night. The average Ldn value was 73.28 +/- 8.51 dB[A] [Range: 55.1 - 87.3]; The Traffic noise index [TNI] was 80.62 +/- 15.88 dB[A] [Range: 49.4 - 115.8]. The computed data were mapped by utilization of Geographic information system methodology that allowed the visualization and identification of the extent and distribution of sound pollution across the study area. This proves to be an ideal tool for carrying out noise impact assessments in urban settings. The study reveals that present noise level in all the locations exceeds the prescribed limit. Based on the finding, it can be mentioned that the population in this industrial town are exposed to significantly high noise level, which is caused mostly due to road traffic. The study reveals that vulnerable establishments like schools and hospitals are subjected to significantly high noise level throughout the day and immediate mitigatory measures are required to alleviate the problem

Study of precipitation chemistry over an industrial city

The growing trend of industrialization has marked impact on the atmospheric chemistry around the globe. Such impacts are also predicted for developing countries like India. Acid precipitation due to secondary pollutants is one of them. The present investigation was conducted with an aim of studying the precipitation chemistry over Asansol city, India during the monsoon season. The rain water samples, collected on event basis during the period of June to September 2006, were analyzed for HCO3[-], C1[-], S04[2-], NO3[-], NH4[+], K[+], Na[+], Mg[2+], Ca[2+] and pH using standard procedures. The study revealed that the precipitation was alkaline in nature with mean pH value of 6.08. Dominant anion in rain water samples was HCO3[-] [36%], whereas Ca[2+] was highest among the cations [53%]. The observed acidic events, based on pH value, were only 17%, indicating the alkaline components effectively neutralize rain water over the area. This was also supported by the total alkaline to acid ion ration of 1.05. The ratio of [NO3[-]+C1[-]] and SO4[2-] was >1, indicating that acidic properties were influenced by HNO3 and HC1. In the ratio between [Ca[2+]+NH4[+]] and [NO3[-]+SO4[2-]], values >1 were obtained, indicating significant alkaline influence, which effectively prevented acid depositions in the area