985 resultados para Atmospheric pollution


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Description based on: 26th (31st Mar. 1944).

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Peatlands can be damaged by deposition of pollutants from the atmosphere – often termed ‘ acid rain ’ . This results from the release of sulphur and nitrogen pollutants into the atmosphere . Originally associated with the Industrial Revolution, ‘acid rain’ was first described by Robert Angus Smith, a Manchester chemist of the 1800s , whose obser vations were made in close proximity to the peatlands of the South Pennines. Sulphur dioxide (SO 2 ) pollution, which is mainly emitted from coal burning power stations, peaked in the 1970s and has since decreased by over 90% due to emission controls and ch anges in energy supply. N itrogen ous air pollutants have decreased less . N itrogen oxide (NO x ) emissions , which are mainly from vehicle s , have decreased by two thirds since their peak in 1990 , but the decrease in ammonia ( NH 3 ) emissions , which are mainly from intensive livestock farming, is much less certain and may be only about 20%.

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Human and ecosystem health impacts imposed by water pollution are a major problem in the urban areas of Sri Lanka. A primary source of pollutants to urban water sources is atmospheric particles. Hence, it is important to develop a detailed understanding of atmospheric particle characteristics, their sources of origin and the transport pathways. Several research studies have been conducted in Sri Lanka on atmospheric pollution and these studies have tended to differ in their scope, study region and the investigated pollutants. The objectives of this paper are: (1) to report the outcomes of a detailed state-of-art literature review of atmospheric pollution related studies in Sri Lanka to understand the current trends and (2) to discuss the future research activities necessary to generate the important knowledge required for the development of effective strategies to control the adverse impacts of atmospheric pollution on urban waterways.

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The contamination of electrical insulators is one of the major contributors to the risk of operation outages in electrical substations, especially in coastal zones with high salinity levels and atmospheric pollution. By using the measurement of leakage-currents, which is one of the main indicators of contamination in insulators, this work seeks to the determine the correlation with climatic variables, such as ambient temperature, relative humidity, solar irradiance, atmospheric pressure, and wind speed and direction. The results obtained provide an input to the behaviour of the leakage current under atmospheric conditions that are particular to the Caribbean coast of Colombia. Spearman’s rank correlation coefficients and principal component analysis are utilised to determine the significant relationships among the different variables under consideration. The necessary information for the study was obtained via historical databases of both atmospheric variables and the leakage current measured in over a period of one year in a 220-kV potential transformer insulator. We identified the influencing factors of temperature, humidity, radiation, wind speed and direction on the magnitude of the leakage current as the most relevant.