How fossil fuels may affect the environment #
- Almost all air pollutants are gases from burning of fossil fuel.
Smoke #
- tiny particles of sooth (carbon) suspended in the air, which are produced from fossil fuels, particularly coal & oil. It has a number of harmful effects:
- 1. When breathed in, smoke may blacken the alveoli, causing damage to their delicate epithelical lining, it also aggravates respiratory aliments e.g. bronchitis.
- 2. While it remains suspended in the air, it can reduce the light intensity at ground level. This may lower the overall rate of photosynthesis.
- 3. Deposits of smoke / more particularly soot may coat plant leaves, reducing photosynthesis by preventing the light penetrating, by blocking the stomata.
- 4. Smoke, soot & ash become deposited on clothes, cars & buildings. These are costly to clan.
sulphur dioxide #
- It may increase soil fertility in areas where sulphates are deficient / even help to control diseases such as black spot of roses by acting as a fungicides , it’s affect concentration are largely harmful.
- 1.It causes irritation of the respiratory system & damage to the epithelical lining the alveoli; it can also irritate the conjunctiva of the eye.
- 2. It reduces the growth of many plants e.g. barley, wheat, lettuce, while other such as lichens may be killed, sulphur is soluble in water. The sulphurous & sulphuric acid. The rainfall therefore has a low pH & is known as acid rain, lakes in the region affected by acid rain are extremely acidic & many species with in them have been killed.
Carbon dioxide #
- Carbon dioxide is transparent to incoming shortwave radiation from the sun but absorbs strongly long wave radiation which the air re- radiates into space therefore traps going radiation warming the lower atmosphere which in turn radiates energy back to the surface of the earth.
- The rise in temperature i.e. so called greenhouse effect will cause the expansion of the oceans & gradual melting of the polar ice caps, with consequent rise in sea level.
- This would in turn cause flooding in low lying land, upon which it happens, many of the world’s capital cities lie.
Carbon monoxide. #
- (Co) occurs in exhaust emission from cars & other vehicles.
- It is poisonous on account of having an affinity for hemoglobin than oxygen.
- Upon combining with hemoglobin it forms a stable compound which is prevents oxygen combining with it.
- Continued inhalation leads to death as all hemoglobin combine with carbon monoxide, leaving non transport oxygen.
- In small concentration it may cause headaches
Nitrogen oxides #
- Nitrogen oxides e.g. nitrogen dioxide are produced by the burning of fuels in car engines & emitted as exhaust.
- In themselves, they are poisonous, but importantly, they contribute to the formation of the photochemical smog.
- Under certain climatic conditions pollutants become trapped close to the ground.
- The action of sunlight on the nitrogen oxides in these pollutants cause them to be converted to peroxacyl nitrate (PAN).
- The compounds are much more dangerous causing much more damage to vegetation & eye lung irritation in man
The use and effects of nitrogen containing fertilizers in agriculture. #
- Nitrogen containing fertilizers increase yields
- When a farmer rotates crops nitrogen containing fertilizers do not cause much harm
- When a farmer applies the correct amount of fertilizer no harm occurs;
- Problem arises when excess fertilizer IS applied;
- Excess application of fertilizer causes eutrophication of water bodies;
- Eutrophication of water bodies cause algal blooms;
- Algal blooms decompose and reduce the amount of oxygen in water bodies;
- Cause death of aquatic organisms;
- Due to lack of oxygen
Lead #
- Most lead in the air is emitted from car exhaust.
- Tetraethyl lead (TEL) is added to petrol as anti-knock agent to help it to burn more evenly in car engine.
- The lead absorbed by the lung could have the following adverse effects.
1. Digestive problem e.g. intestinal colic.
2. Impering the functions of the kidney.
3. Nervous problem including convulsion.
4. Brain damage & mental retardation in children. - Anti-knock agent which do not contain lead exist & in some countries legislation permits only this time.
- They are however, most expensive & cause an increase in the actual cost of petrol.
Methods of controlling air pollution.
- Use of non-lead & anti knock & the removal of pollution such as sulphur before smoke is emitted from the chimney by passing the smoke through a spray of water at which much of the sulphur dissolves.
- Use of electric cars is a further means of limiting air pollution
- Using catalytic converters to make sure that there is complete combustion.
- Using other forms of fuel which do produce the gases e.g. methane
The effects of deforestation to the environment #
- removal of forestry canopy;
- rainfall cannot easily penetrate the surface runoff;
- More rapid run off;
- leads in soil erosion;
- silting of water reservours/dams/rivers;
- increases atmospheric carbon dioxide;
- results in global warming/greenhouse effect;
- reduces transpiration;
- leads to less rainfall, atmospheric moisture/drought/desertification
Measures #
- Practicing re- forestation and afforestation.
- Using other sources of fuel instead of wood e.g. nuclear fuel, wind and water.
- Electrify rural areas.
