Types of air Pollution
Greenhouse Effect
Greenhouse gases include H2O, CO2, CH4, and other gases. These gases, present in the atmosphere, allow solar radiation (sun rays), radiation on the electromagnetic spectrum, to enter the Earth’s atmosphere. When the radiation reflects off of the surface of the Earth, the radiation loses some of it energy. Some of this radiation has enough energy to escape the atmosphere, but some does not. The greenhouse gases trap this lower energy infrared radiation in the atmosphere, which then warms the surface.
The greenhouse effect has gotten a bad rap recently. It has been blamed for global warming. In reality, life as we know it would die without the greenhouse effect. The greenhouse gases trap heat during the day. This heat is then slowly released at night. Since it is retained at night, temperatures remain warm at night. Without these gases, there would be a larger swing in temperatures at night.
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For example, in the desert, there is less water. During the day, the temperature gets extremely hot, due to the direct sunlight. But, there is very little water, or other greenhouse gases, and not much of that heat is retained. At night, in the desert, if can often go below freezing. If this were to happen all over the world, the plants that we grow will freeze at night, and we will not be able to grow crops. Greenhouse gases provide the stored heat we need to continue life as we know it.
Global Warming
Global Warming
Global warming is the trend of the average surface temperature of the earth increasing. Global warming is a theory that suggests that the increase of greenhouse gases in the atmosphere has caused the overall global temperature to rise. Is there evidence that global warming is occurring? The largest piece of evidence is the increase of average global temp. of 1 OF in the past 100 years. This average of 1OF is not consistent over the whole planet. For instance, the average temperature at the poles has increased about 2 - 5 OF, where the average temperature at the equator has not really increased.
Effects of global warming are hypothesized to be:
1) Melting of polar ice caps, which could cause a raise in the ocean water levels.
2) Increases population density - Some of the newly flooded areas will cause people and animals to move inland.
3) Extreme weather events - more water in the atmosphere will increase the severity of weather events. More blizzards and more hurricanes will likely occur.
4) Change in growing seasons - An increase in temperature will mean that the summer growing seasons may start earlier and end later. This could require farmers to adjust what they grow in certain areas.
5) Because of more water as a liquid and warmer temperatures, more water can evaporate into clouds. Since water is a greenhouse gas, more water in the atmosphere can raise the temperature even more, which can evaporate more water into the atmosphere, which can raise the temperature, etc. (Spiraling effect).
Acid rain and precipitation
Acid precipitation is rain, fog or snow) with a pH in the acidic range of the pH scale (typically with a pH below 5.6).
1) Melting of polar ice caps, which could cause a raise in the ocean water levels.
2) Increases population density - Some of the newly flooded areas will cause people and animals to move inland.
3) Extreme weather events - more water in the atmosphere will increase the severity of weather events. More blizzards and more hurricanes will likely occur.
4) Change in growing seasons - An increase in temperature will mean that the summer growing seasons may start earlier and end later. This could require farmers to adjust what they grow in certain areas.
5) Because of more water as a liquid and warmer temperatures, more water can evaporate into clouds. Since water is a greenhouse gas, more water in the atmosphere can raise the temperature even more, which can evaporate more water into the atmosphere, which can raise the temperature, etc. (Spiraling effect).
Acid rain and precipitation
Acid precipitation is rain, fog or snow) with a pH in the acidic range of the pH scale (typically with a pH below 5.6).
Acid precipitation is caused by the reaction of SO2, NOx, and CO2 with water in the atmosphere:
Examples: SO2 (g) + H2O (g) --> H2SO3 (aq)
CO2 (g) + H2O (g) --> H2CO3 (aq) NOx (g) + H2O (g) --> HNOx+1 (aq) SO2 and NOx come from the combustion of fossil fuels or industrial process, while CO2 is mostly natural, but is increased by human activities. See diagram to see some of the sources of acid pollution:
Effects of acid precipitation: 1) Destruction of trees and plants sensitive to changes in pH. 2) Alteration of the pH of certain bodies of water, 3) Death of water animals sensitive to low pH. 4) Sores on skin due to overexposure to acids. |