FAQ

Difference between concentrations and emissions

According to article num. 2 of Presidential Decree 203/88, atmospheric pollution represents any change in the common composition or physical state of atmospheric air, due to the presence of one or more matters in amounts and features able to alter normal environmental conditions and air health; these changes may be of direct or indirect harm or prejudice for human health, may prejudice recreational activities and other safe uses of environment, may alter biological resources, ecosystems and even public and private properties.

In order to quantify the atmospheric "pollution degree" emissions must be distinguished from concentrations of pollutant matters.

An emission is the amount of pollutant matter released in the atmosphere from a specific pollutant source and in a specific time interval; an emission is generally expressed in (metric) tons year-1. A concentration is the amount of pollutant matter in atmosphere per volume unit; it is generally expressed in grams per mc-1 and it is used to express values of air quality.

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