On the basis of form of their occurence, pollutants are divided into two categories :
(i) `text(Primary pollutants)` : These are present in the same form in which they are produced. eg. carbon monoxide, DDT
(ii) `text(Secondary pollutants)` : These are formed by reaction between the primary pollutants in the presence of sunlight eg. PAN, Ozone, `HNO_3`, `H_2SO_4` etc. Nitrogen oxides and hydrocarbons react photochemically to produce peroxyacetyl nitrates (PAN) and ozone. The secondary pollutants may be more toxic than the primary once. The phenomenon is called synergism.
On the basis of their degradation, pollutants are divided into two categories :
(i) `text(Biodegradable Pollutants)` : Pollutants which are decomposed or degraded by biological or microbial action are called biodegradable pollutants eg. domestic sewage.
(ii) `text(Non-biodegradable Pollutants)` : Pollutants which are not decomposed or degraded by living organisms or micro organisms are called non-biodegradable pollutants. eg. DDT, glass, plastics, aluminium cans, phenolic compounds, pesticides, radioactive substances, heavy metals like mercury, lead, cadmium etc.
On the basis of their existance in nature, pollutants are divided into two categories.
(i) `text(Quantitative pollutants)` : These are naturally present in nature and are also added by man. These become pollutants only when their concentration reaches beyond a threshold value in the environment. eg. `CO_2`.
(ii) `text(Qualitative pollutants)` : These are not present in the nature but are added in nature only due to human activities eg. insecticides, fungicides, herbicides etc.
On the basis of environmental study pollution is of following types :
`(a)` `text(Air pollution)`
`(b)` `text(Water pollution)`
`(c)` `text(Soil pollution)`
`(d)` `text(Noise pollution)`
`(e)` `text(Radioactive pollution)`
On the basis of form of their occurence, pollutants are divided into two categories :
(i) `text(Primary pollutants)` : These are present in the same form in which they are produced. eg. carbon monoxide, DDT
(ii) `text(Secondary pollutants)` : These are formed by reaction between the primary pollutants in the presence of sunlight eg. PAN, Ozone, `HNO_3`, `H_2SO_4` etc. Nitrogen oxides and hydrocarbons react photochemically to produce peroxyacetyl nitrates (PAN) and ozone. The secondary pollutants may be more toxic than the primary once. The phenomenon is called synergism.
On the basis of their degradation, pollutants are divided into two categories :
(i) `text(Biodegradable Pollutants)` : Pollutants which are decomposed or degraded by biological or microbial action are called biodegradable pollutants eg. domestic sewage.
(ii) `text(Non-biodegradable Pollutants)` : Pollutants which are not decomposed or degraded by living organisms or micro organisms are called non-biodegradable pollutants. eg. DDT, glass, plastics, aluminium cans, phenolic compounds, pesticides, radioactive substances, heavy metals like mercury, lead, cadmium etc.
On the basis of their existance in nature, pollutants are divided into two categories.
(i) `text(Quantitative pollutants)` : These are naturally present in nature and are also added by man. These become pollutants only when their concentration reaches beyond a threshold value in the environment. eg. `CO_2`.
(ii) `text(Qualitative pollutants)` : These are not present in the nature but are added in nature only due to human activities eg. insecticides, fungicides, herbicides etc.
On the basis of environmental study pollution is of following types :
`(a)` `text(Air pollution)`
`(b)` `text(Water pollution)`
`(c)` `text(Soil pollution)`
`(d)` `text(Noise pollution)`
`(e)` `text(Radioactive pollution)`