12-06-2013, 02:54 PM
POLLUTION: CAUSES AND CONSEQUENCES
POLLUTION.ppt (Size: 912.5 KB / Downloads: 43)
What is pollution?
Pollution is the introduction of harmful substances or products into the environment
We will be examining 3 main parts of pollution
Water Pollution
Air Pollution
Land Pollution
Causes of Water Pollution
Factors that contribute to water pollution can be categorized into two different groups
Point sources
Non-point sources
Point sources are the easiest to identify and control
Non point sources are ambiguously defined and harder to control
Causes of Air Pollution
One of the main causes of air pollution is the release of carbon dioxide into the atmosphere, this happens because of Deforestation and fossil fuel burning
Sulfur dioxide is another air polluter and is released into the atmosphere by the burning of sulfur containing compounds of fossil fuels. Sulfur oxides are very dangerous to humans at a high concentration. Sulfur in the atmosphere is responsible for acid rain
Consequences of Air Pollution
CO2 is a good transmitter of sunlight, but it also partially restricts infrared radiation going back from the earth into space, which produces the so-called greenhouse effect that prevents a drastic cooling of the Earth during the night
Increasing the amount of CO2 in the atmosphere reinforces this effect and is expected to result in a warming of the Earth's surface
CO2 in atmosphere GLOBAL WARMING
Acid Rain
When emissions of sulfur dioxide and nitric oxide from stationary sources are transported long distances by winds, they form secondary pollutants such as nitrogen dioxide, nitric acid vapor, and droplets containing solutions of sulfuric acid, sulfate, and nitrate salts
These chemicals descend to the earth's surface in wet form as rain or snow and in dry form as a gases fog, dew, or solid particles, it is known as acid rain or acid deposition
With the introduction of petroleum to replace coal economies in countries, photochemical smog has become predominant in many cities, which are located in sunny, warm, and dry climates with many motor vehicles
Worst episodes of photochemical smog tends to occur in summer
Agriculture
As there are more and more people inhabiting the earth, food is in higher demand and so forests are chopped down and turned into farmland
In addition, herbicides, pesticides, artificial fertilizers, animal manure (poop) are washed into the soil and pollute it
Consequences of Land Pollution
Land pollution exterminates wild life
Acid rain kills trees and other plants
The vegetation that provides food and shelter is destroyed
Land pollution can seriously disrupt the balance of nature, and, in extreme cases, can cause human fatalities
Pesticides can damage crops; kill vegetation; and poison birds, animals, and fish. Most pesticides kill or damage life forms other than those intended. For example, pesticides used in an effort to control or destroy undesirable vegetation and insects often destroy birds and small animals. Some life forms develop immunity to pesticides used to destroy them