Pollutants, Biology

These are solid, liquid or gaseous substance present in the atmosphere in such concentrations, as may be or tend to be injurious to human beings or other living creatures, plants and property.

                                                                     Or

Any substance present in environment in such a concentration which adversely alters the environment by damaging the growth rate of a species and by interfering with the food chain is toxic and affects health, comfort and property.

eg: smoke from domestic and commercial areas and industries, radioactive substances from nuclear power plants, discarded and waste household articles.

The air pollutants are classified on the basis of origin and physical state.

(a)   On the basic of origin: pollutants are of two types:

(i)    Primary pollutants:

Those pollutants that are emitted directly from the sources and are present in the atmosphere in the same form in which they were emitted area called primary pollutants eg.  CO, NO2, SO2 and hydrocarbon, emitted by burning of coal, fuels, vehicular exhaust and NH3 emitted from agricultural processes. Radioactive pollutants produced by nuclear explosions and process (radon gas) pollen grains, micro organisms, bacteria, spoils.

(ii) Secondary pollutants:

Those pollutants that are formed in the atmosphere by chemical interactions between primary pollutants and atmospheric constituents are called secondary pollutants. These are usually formed by oxidation, hydrolysis and photochemical reactions e.g. SO3, O3,  peroxyacylnitrate, (PAN), aldehydes and ketones etc.

Hydro carbons + (NO)x + sunlight          PAN, peroxides, formaldehyde + aldehyde + acrolin

 (b)  On the basic of state of matter:  pollutants are of two types:

(i)     Gaseous pollutants:

The pollutants which occur in gaseous state at normal temperature and pressure e.g CO, CO2, SO, NO2, hydrocarbon and photochemical oxidants.

(ii)   Particulate pollutants:

All atmospheric substances that are not gases but may be suspended droplets, solid particles or mixture of the two are generally referred as particulates.

Posted Date: 7/12/2012 1:36:26 AM | Location : United States







Related Discussions:- Pollutants, Assignment Help, Ask Question on Pollutants, Get Answer, Expert's Help, Pollutants Discussions

Write discussion on Pollutants
Your posts are moderated
Related Questions
What is gluconeogenesis? Highlight its significance giving any two examples Gluconeogenesis (i.e synthesis of new glucose) is the synthesis of carbohydrate from non-carbohydrat

(a) Trace the succession of plants on a dry bare rock. (b) How does phosphorus cycle vary from carbon cycle?

Q. Working of serotonergic cell bodies? The major site of serotonergic cell bodies is in upper pons and the midbrain, specifically the median and dorsal raphe nuclei and to a l

As you travel south from the tundra you will enter the circumpolar belt of coniferous forests which stretches across North America to Eurasia, this region is called taiga, a world

What surrounds a plant cell

Define Procedure for Testing the Presence of Proteins in Milk? 1. Add 0.5 ml of alcohol to 0.5 ml milk.  Alcohol helps in curdling the milk. 2. Observe for the curdling of m

Shape and size of protiens Fibrous proteins for example: keratin in hair, actin and myosin in muscles, and collagen. Globular proteins, for example enzymes and antibo

Q. Important Herbaria? The herbarium is a place where dried and mounted specimens are stored according to any recognised system of classification. Special attention is paid tow

Q. What is the life cycle of Plasmodium vivax? The vector mosquito bites a infected person and ingests female and male gametocytes of the parasite. Within the insect gut the ga

What is Waist-to-Hip Ratio? Waist-to-Hip Ratio (WHR) is defined as the measurement of waist circumference divided by hip circumference. For example, if a person's waist measure