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
When an individual is exposed to foreign serum antigen then a combination of symptoms are produced which is known as serum sickness.

1. Explain the challenges and advantages of having internal gills over external gills for gas exchange? 2. Explain how increased stress levels can affect hormones which ultimate

what is sperm

Q. What do you mean by Oxalates? Oxalates are widely distributed in plant foods mostly in the form of calcium salts. Oxalates are known to interfere with calcium absorpti

Electron acceptor is a molecule which forms the part of the electron transport system which transfers electrons ejected by chlorophyll during the process of photosynthesis. Part o

Explain the De Bakey Type I Dissection? De Bakey Type I Dissection :  Initial steps of the operation are same as previously described. Provision for deep hypothermic ci

Oxidized starch Coating and sealing  agent, emulsifier, dough conditioner for bread, binding agent as gum Arabic replacer, lemon curd manufacture, salad cream, mayonnaise.

Q. Fish identity card. How are fishes characterized according to examples of representing beings, skin, basic morphology, circulation, nitrogen waste, respiration, thermal control

Q. Explain the Spring clip model? The spring clip model differs from the spring model in a way that the force applied is comparatively slower. This also depicts elasticity or p

Define requirements of Iodine during pregnancy period? You would be already aware that maternal iodine deficiency leads to cretinism in the off spring. Hence, the material diet