Air Pollution And Our Atmosphere

AIR POLLUTION AND OUR ATMOSPHERE

Driving down the 101 Freeway on my way to visit some friends in Los Angeles, I suddenly came up with an idea for a paper. The idea was Air Pollution, and the idea was triggered by the enormous amounts of debris, smog, and atmospheric contents that distinctly hovered over the city before my eyes. My question was how does all this pollution form and why is it so thick over here? It all began with defining Air Pollution, which is the addition of harmful substances to the atmosphere resulting in damage to the environment, human health, and our quality of life. Air pollution makes people sick, it causes breathing problems, promotes cancer, harms plants, animals, and at the same time it's slowly destroying the ecosystems that we live in. Air pollution is opening the gate to several other global problems such as; global warming, smog and thermal inversion, ozone depletion, the greenhouse effect, and acid rain. Those are all examples of human caused air pollution also referred to as anthropogenic (Christopherson 98). There are not only human caused pollution problems, but also natural occurring events that are affecting our globe as a whole, such as volcanic eruptions.

Air pollution is causing many changes in earth's atmospheres. These changes have made it so; more harmful radiation from the sun is reaching earth. However, at the same time, our polluted atmosphere is acting as an insulator, making it so that heat from the sun cannot escape back into space and this is leading to a rise in global average temperatures (Christopherson 130). Scientists predict that the temperature increase, also known as global warming, will affect our world food supply, alter sea levels, make weather more extreme, and increase the spread of tropical disease (Hart). Just in the past year, we have seen many cases of extreme weather all over the world from the tsunami in South-East Asia that killed more than one hundred thousand people, to hurricane Katrina in the eastern part of the United States that also caused many deaths.

Most air pollution comes from one human activity: the burning of fossil fuels. The fossil fuels that are included are: natural gas, coal, and oil. We use fossil fuels to power industrial processes and more common, driving automobiles (Christopherson 138). All over the world, more and more people are driving and this is causing a huge pollution problem. Once in the atmosphere, pollutants can undergo chemical reactions that produce additional harmful chemicals. Not only is pollution being concentrated in high populated areas, but the weather is blowing the pollution across the globe and damaging environments far from the original source (Hart).

Local and regional pollution take place in the lowest layer of the atmosphere, the troposphere, which extends from Earth's surface to about 11 miles up. The troposphere is the layer where weather occurs (Christopherson 71). Pollution sources tend to be concentrated in cities because of the large amount of automobiles in cities, such as Los Angeles. There is a process known as thermal inversion that is causing many harmful environmental and health effects in cities. When thermal inversion happens, a layer of cooler air is trapped near the ground by a layer of warmer air above. This results in the pollutants being trapped in the lower layer (Christopherson 78). Places that are surrounded by mountains are especially vulnerable by thermal inversion because the mountains trap the polluted air. Smog is intense local pollution usually trapped by a thermal inversion (Christopherson 80). Los Angeles is a perfect example of this. When you drive over the mountains and look down into L.A., you can see the large amount of smog that is trapped in the valley, especially during the summer. The pollution trapped between the cooler and warmer air is basically sitting atop of cities and causing many health problems. Asthma cases have increased over the past decade, as well as, many lung related problems. Burning gasoline in motor vehicles is the main source of smog in most areas today. Smog contains ozone, a form of oxygen gas. Ozone in the lower atmosphere is a poison; it damages vegetation, kills trees, and irritates lungs (Hart). Nevertheless, air pollution is not only local, but global as well.

Air pollution can expand beyond a local region to cause global effects. The stratosphere, the layer of the atmosphere between 10 miles and 30 miles above sea level, is full of ozone. Up at the stratospheric level, ozone forms a protective layer that is essential for our protection from the suns' rays. The ozone absorbs UV-B rays. UV-B damages DNA and increases the risk of cancer in humans when we are exposed to it. Because of its protective function, the ozone layer is essential to life on Earth. Several pollutants attack the ozone layer (Christopherson 71). Among them is the class of chemicals known as chlorofluorocarbons (CFCs), formerly used as refrigerants used in air conditioners. Once the CFC's get to the stratosphere, ultraviolet radiation breaks the CFC molecules apart, releasing the chlorine atoms they contain. These chlorine atoms begin reacting with ozone, breaking it down into ordinary oxygen molecules that do not absorb UV-B (Christopherson 73-74). A single chlorine atom can destroy up to 100,000 ozone molecules in the stratosphere (Hart). As a result, the ozone layer is thinning and in some parts of the world such as the Antarctic region, the ozone is completely destroyed: this is causing an increase in skin cancers. Luckily, the amount of CFC's has been reduced dramatically in the past decade and will soon hopefully be prohibited worldwide; however, the CFC's that have already been put into the lower atmosphere, will continue to make their way up to the stratosphere for decades to come (Hart).

Another anthropogenic problem with air pollution is the increase of greenhouse gases: carbon dioxide is the most significant of the gases, as well as, methane, nitrous oxide and CFC's (Christopherson 100). This gas lets the sunlight into Earth's atmosphere, but instead of letting it back out, it is reflected back down trapping the heat in our atmosphere: this is the greenhouse effect. It's been predicted that an increase in these gases in the atmosphere will make the Earth a warmer place. They expect a global rise in