Contamination in the natural environment by contaminants or pollutants is known as pollution. Types of pollutions are noise, energy, heat, light and chemical substances. Pollution is classified into 2 categories and they are point source or nonpoint source pollution. Pollution control explains or describes the activities that reduce the amount of pollution generated by a process. Pollution can be controlled in the environment by refuse disposal systems such as sanitary landfills, emission control systems for automobiles, sedimentation tank.
The impact factor of journal provides quantitative assessment tool for grading, evaluating, sorting and comparing journals of similar kind. It reflects the average number of citations to recent articles published in science and social science journals in a particular year or period, and is frequently used as a proxy for the relative importance of a journal within its field. It is first devised by Eugene Garfield, the founder of the Institute for Scientific Information. The impact factor of a journal is evaluated by dividing the number of current year citations to the source items published in that journal during the previous two years.
Last date updated on June, 2014