CHEMISTRY - Pollutants

Pollutants are those substance which introduce harmful gases in the air or in soil or in water which harmful for living organism i.e. harm the human as well as the plants. Pollutants can be classified as :-
1. Primary and Secondary Pollutants :-

* Primary Pollutants :- Primary pollutants are those which after their formation enter the environment and remain as such. For example, nitric oxide(NO) formrd by bacterial decay or by lightning flashes ( resulting into combination of nitrogen and oxygen of the air ) becomes a pollutant if present in excessive amount.
* Secondary Pollutants :- Secondary pollutants are those harmful material which are formed by chemical reactions between the primary pollutants in the atmosphere or hydrosphere. These are the pollutant which is formed by reaction between the primary pollutants and the other elements in the atmosphere. For example, hydrocarbons and oxides of nitrogen which are primary pollutants react together in the presence of sunlight to form certain compounds which are also harmful. The compound thus formed are called secondary pollutants.

<b>2. Biodegradable and Non-Biodegradable Pollutants :-</b>

* Biodegradable Pollutants :- Biodegradable pollutants are materials such as domestic sewage, cow-dung etc. Which are easily decomposed by the microorganism either by the nature itself or by suitable treatment and thus are not harmful but if these are present in excess in the environment, they do not undergo degradation completely and thus become pollutants.

* Non-Biodegradable Pillutants :- Non-biodegradable pollutants are materials such as mercury, alluminium, DDT etc. Which do not undergo degradation or degrade very slowly but their presence even in very small amounts in the environment is very harmful for the humans as well as plants. They may react with other compounds present in the environment and produce even more toxic compounds.

Due to these pollutants our environment is going to a unbalance today . Due to the pollution the result in a depletion in the ozone layer. Which is very important for the earth all human beings and plants and animals. Ozone layer protect the human being from harmful ultrviolet radiations.