Poor air quality is the culprit for the consequences that are being suffered by many human and plant communities. Air pollution, smog, or acid rain; it may be called whatever you like, it is the effects that it is causing that are important. Although many people associate smog with Los Angeles, it is not the only area that has been effected by poor air quality. Many national parks, aquatic systems, and other populated areas are showing major signs of air pollution. 'A large pollution study revealed that when smog increases in the Los Angeles Basin area, there is a big jump in the number of people hospitalized for lung and heart problems (Dreher 1998).' The effects of air pollution can be seen even below the levels that are indicated by air quality standards, since people respond differently to poor air quality. 'Concentrations of harmful chemicals in the air have been proven to inflame and destroy lung tissue and weaken the lung defenses.

Germs and dirt are normally trapped in the mucus in our air passages and removed by tiny hairs called cilia before entering our lungs. Polluting chemicals can paralyze the tiny cilia, allowing germs to build up in mucus or leave our body poorly protected against disease (Dreher 1998).' 'The U. S. Centers for Disease Control and Prevention (CDC) estimates that pollution is associated with between 50, 000 and 120, 000 deaths every year (Dreher 1998).' The people most affected by poor air quality are people with asthma, bronchitis, heart disease, and similar health conditions. Studies have also shown that children and the elderly may be affected more than adults. 'Children are affected more severely than adults because theft airways are relatively narrower and more easily obstructed, and their oxygen demand relative to body weight is higher, resulting in relatively larger inhaled volumes (van Bree 1993).' The major pollutants that comprise poor air quality, or smog, are: sulfur dioxide, nitrogen dioxide, carbon monoxide, volatile organic compounds (VOCs), ozone, suspended particulates, and greenhouse gases (carbon dioxide and methane).

Studies have shown that ozone produces the most negative effects on humans. 'These effects include coughing, difficulty in breathing, chest tightness, and nausea; reduced lung functions with possible lung inflammation, hyperactivity, and alterations in lung clearance; special problems for persons with respiratory diseases; and decreased ability to exercise strenuously. Laboratory animal studies suggest there may be biochemical, immunological, and morphological changes in respiratory tract tissues (van Bree 1993).' Air pollution can also have effects that are less serious, but, nevertheless harmful. 'It can make your eyes water, irritate your nose, and cause headaches, coughing, sneezing, sore throat, dizziness and nausea (Dreher 1998).' To alert people of pollutant levels, the Environmental Protection Agency (EPA) reports a Pollutant Standards Index (PSI) every day. The PSI considers the levels of carbon monoxide, ozone, nitrogen, sulfur dioxide, and particulate matter in the air and uses a scale (from 1-500) to show the combined levels of pollutants in the air on a given day. If the PSI level is less than 50, then the air is considered to be healthy.

However, a PSI of 300 or more may be hazardous to your health. When the PSI is above 400, the EPA highly recommends that everyone in the general population should remain indoors. Also at PSI levels of above 400, 'premature death of ill and elderly persons may result (Dreher 1998).' Even PSI levels of around 100 are considered to be unhealthful; the EPA suggests that 'susceptible individuals, such as those with heart or lung disease, should minimize outdoor activity (Underwood 1998).' For the above reasons it is very important to be aware of the PSI levels in the areas in which you live. Smog does not only occur in Los Angeles! Many people believe that air pollution is mostly caused by automobile emissions, this is not necessarily the case. Many of the gases that were mentioned above do come from automobiles, but they also come from incinerators, power plants, construction sights, etc.

In fact, the pollutant that seems to cause the most harmful effects on humans is the coarse particulate matter. Surprisingly, scientists discovered that the hospitalizations of many people, as a result of air pollution, were more closely connected with increases in the amounts of coarse (large particles in the air that came mainly from grit blown from unpaved roads and construction areas) particles suspended in the air (Dreher 1998). Mostly, they amount to small, unnoticed changes in lung tissue that build up over time, possibly leading to earlier onset of lung disease and shorter lifespans (Brennan 1993). This shows that it is very important to take precautions as to avoiding long exposure to areas consisting of dusty dirt roads and construction sights. Air pollution not only affects human health, it also affects the health of our environment. 'Air pollution damages water ways, destroys trees, and clouds views in many of America's national parks (Tennesen 1997).' The National Park Service (NPS) has no authority over pollution that comes from outside park boundaries.

Therefore, they can only try to make the surrounding areas aware of the problems emanating from the pollution. Air pollution has begun to seriously affect our national parks. From the Great Smoky Mountains to the Grand Canyon, the pollution can easily, and often does travel hundreds of miles. So, even though the pollution is not necessarily occurring in the areas of the parks, it is still travelling there from miles away. 'Though the problem is worse in the East -- affecting plant life as well as visibility -- air pollution is a factor in virtually every park in the United States (Tennesen 1997).' Although the Great Smoky Mountains National Park is some 30 miles away from Knoxville, Tennessee, the air pollution created from the large population in the city has carried over and has had very grave effects on the national park. 'The damage the mountains sustain comes primarily from acid rain and ozone created from sulfur and nitrogen emissions.

Clouds over the Smokies can be a thousand times more acidic than natural rainfall -- and more than 30 species of trees and plants in the park show injury from ozone, including black cherry, yellow poplar, blackberry, and milkweed (Tennesen 1997).' At Grand Canyon National Park in Arizona, the affects of air pollution aren't necessarily shown through plant life because there isn't much of a plant life in the area. The area in Arizona is known for it's spectacular rock formations within the enormous canyon. Because of air pollution, those beautiful formations cannot always be seen. 'Pollution diminishes the views on 90 percent of the days. On some days, visitors to the South Rim can see only half as far as those who toured the park when it was dedicated in 1919 (Tennesen 1997).' Carl Bowman, an air quality scientist at the national park said that, 'Instead of those huge erosional forms and brilliant colors, you often see only vague blue masses.' Besides the effects that air pollution has had on the Grand Canyon and Great Smoky Mountains, it has had an amazing effect on the plant life of nearly all of the national parks in the country.

The levels of ozone and acid rain seem to have the most detrimental effects on the plant communities in these parks. 'Ozone affects the leaves of a number of plants, producing purple to dark brown stippling that can hinder plant photosynthesis, physiology, and growth (Tennesen 1997).' Acid rain has been shown to have terrible effects on the underground systems of plants rather than their above ground structures. 'Acid rain enters the soil and leaches away calcium, potassium, and magnesium, essential nutrients for plants. It can also loosen metals, releasing them from the soil into surface and groundwater where they can affect plant growth and aquatic life (Tennesen 1997).' Air pollutants can weaken trees extremely by starving and poisoning them, and burning their leaves. Once the trees have been weakened, all they need are some harsh weather conditions to finish them off.

Another study conducted on the affects of ozone on plants found that brittle leaves on some plants may be caused by ozone damage. The study tested the affects of ozone on major U. S. crops such as soybeans, green beans, barley and wheat. All crops showed the same brittle characteristics after exposed to common ozone levels. This may explain the estimated $5 billion annually in reduced yields for farmers (Bock 1988).

Another common organism that has been extremely affected by air pollution is lichen. Lichens are weather-hardy and widely distributed life forms that grow on rocks, stumps, shingles, and tree branches (Bennett 1996). A common misunderstanding of lichen is that they are a single organism, but they are actually formed of two separate organisms that depend on one another for survival (a fungus and an alga). 'Because they lack a cuticle or skin, they are exposed directly to the atmosphere and, along with nutrients and water, they soak up lead, sulfur, zinc, cadmium, and an array of other chemical and heavy metal air pollutants (Bennett 1996).' Due to the lichens sensitivity to air pollution, they are used as indicator organisms for air pollution levels.

Lichens have been proven to accurately show levels of pollution even in remote and seemingly pristine environments. Although lichens have come in handy as indicator organisms, some species are at risk of becoming endangered or extinct. 'Chronic exposure over long periods of time could result in the loss of species well beyond the dozen lichen deserts now identified in North America (Bennett 1996).' Air pollution has negatively affected so many different aspects of our environment, including us, that it is a wonder why it is not treated as a big issue. Is it because the effects of poor air quality are so anticlimactic? Although the Environmental Protection Agency has introduced a Clean Air Act, they still do not seem to be entirely concerned with the air quality's affect on humans.

'Now the EPA wants only to issue code red warnings when pollution is 50 percent higher than the standards (Borenstein 1999).' This may result in higher incidences of death among the elderly and other people most sensitive to the affects of air pollution. If the EPA follows through with their proposed warning changes, it may give the population the idea that the air quality has improved when it really hasn't, it may even be worse than it has ever been before. Another problem with the EPA is that they have not defined who is sensitive to air pollution. They may tell us that people who are sensitive to air pollution should stay indoors on a given day, but we don't know if we are sensitive to air pollution or not.

'The lung association and independent environmental health professors say about one out of three people are sensitive to air pollution. This includes people who work or play outdoors for long periods of time, young children, people with chronic lung diseases, asthmatics and the elderly (Borenstein 1999).' This engulfs and enormous population. Shouldn't the EPA make sure that we are aware of this statistic? In conclusion, it seems that the Environmental Protection Agency could be somewhat more concerned with the effects of air pollution on the plant and animal communities. Would it really cost them much money to regulate warnings, and to actually enforce their Clean Air Act? References Bennett, James P. June 1996.

Air Pollution is Decimating Lichens. USA Today (Magazine). p. 11. Bock, Jane.

July 1988. Brittle Plants Point to Ozone Damage. Science News. p. 28. Borenstein, Seth.

February 1999. Activists: EPA's Smog Standard Means Fewer Will Be Alerted When Air Goes Bad. Knight Ridder / Tribune. p. K 0174. Brennan, Pat.

July 1993. Smog Science Seeks Answers in Past, Present, Future. Knight Ridder / Tribune. p. 0714 K 7953.

Dreher, Nancy. March 1998. How Pollution Affects Our Health. Current Health 2. pp. 13-15.

Tennesen, Michael. November-December 1997. On a Clear Day: Air Pollution Damages Waterways, Destroys Trees, and Clouds Views in Many of America's National Parks. National Parks. pp.

26-29. van Bree, Leendert. September-October 1993. Air Pollution. World Health. pp.

16-17.