| Scientists have estimated that every day, an average | | | | air pollutants are nitrogen oxides, carbon monoxides, |
| person inhales about 20,000 liters of air. Every time | | | | and organic compounds that can evaporate and enter |
| we breathe, we risk inhaling dangerous chemicals that | | | | the atmosphere. Air pollutants have sources that are |
| have found their way into the air. Air pollution includes | | | | both natural and human. Now, humans contribute |
| all contaminants found in the atmosphere. These | | | | substantially more to the air pollution problem. Forest |
| dangerous substances can be either in the form of | | | | fires, volcanic eruptions, wind erosion, pollen dispersal, |
| gases or particles. Air pollution can be found both | | | | evaporation of organic compounds, and natural |
| outdoors and indoors. Pollutants can be trapped | | | | radioactivity are all among the natural causes of air |
| inside buildings, causing indoor pollution that lasts for a | | | | pollution. |
| long time. The sources of air pollution are both natural | | | | Usually, natural air pollution does not occur in |
| and human-based. As one might expect, humans | | | | abundance in particular locations. The pollution is |
| have been producing increasing amounts of pollutants | | | | spread around throughout the world, and as a result, |
| as time has progressed, and they now account for the | | | | poses many threats. Though some pollution comes |
| majority of pollutants released into the air. | | | | from these natural sources, most pollution is the result |
| Air pollution has been a problem throughout history. | | | | of human activity. The biggest causes are the use of |
| Even in Ancient Rome people complained about | | | | fuels in power plants and automobiles that combust |
| smoke put into the atmosphere. The effects of air | | | | fuel. Combined, these two sources are responsible |
| pollution are diverse and numerous. Air pollution can | | | | for about 90% of all air pollution in the United States. |
| have serious consequences for the health of human | | | | Some cities suffer severely because of heavy |
| beings, and also severely affects natural ecosystems. | | | | industrial use of chemicals that cause air pollution. |
| Because it is located in the atmosphere, air pollution is | | | | Places like Mexico City and Sao Paulo have some of |
| able to travel far off places easily. As a result, air | | | | the most deadly pollution levels in the world. |
| pollution is a global problem and has been the subject | | | | Air pollution is responsible for major health effects. |
| of both global cooperation and conflict. Some areas | | | | Every year, the health of countless people is ruined or |
| now suffer more than others from air pollution. Cities | | | | endangered by air pollution. Many different chemicals in |
| with large numbers of automobiles or those that use | | | | the air affect the human body in negative and |
| great quantities of coal often suffer most severely | | | | destructive ways. Just how sick people will get |
| from problems of air pollution. | | | | depends on what chemicals they are exposed to, in |
| Ancient Greek and Roman thoughts began the | | | | what concentrations, and for how long. Studies have |
| environmental sciences. Major philosophers | | | | estimated that the number of people killed annually in |
| advanced differing views that affected others and | | | | the US alone due to environmental pollution-related |
| shield their views for years to come. The early Greeks | | | | diseases could be over 50,000. Older people are highly |
| searched for a reasonable understanding of nature. | | | | vulnerable to diseases induced by air pollution. Those |
| The ideas they developed influenced Europe in the | | | | with heart or lung disorders are under additional risk. |
| future. Thales of Miletus, the founder of the Ionian | | | | Children and infants are also at serious risk. Because |
| school, was the initiator of Greek philosophy on the | | | | people are exposed to so many potentially dangerous |
| environmental sciences. The Ionian school hoped to | | | | pollutants, it is often hard to know exactly which |
| discover the nature of the universe, and how it came | | | | pollutants are responsible for causing sickness. Also, |
| about. According to Thales, everything was | | | | because a mixture of different pollutants can intensify |
| composed of water and the combination of the sun | | | | sickness, it is often difficult to isolate those pollutants |
| and water was the source of life. | | | | that are at fault. |
| Empedocles (c.493-c.433 BC) argued that the universe | | | | Many diseases could be caused by air pollution without |
| was composed of four elements: earth, air, fire, and | | | | their becoming apparent for a long time. Diseases |
| water, which combined in different ways and | | | | such as bronchitis, lung cancer, and heart disease may |
| proportions to produce different results and products. In | | | | all eventually appear in people exposed to air pollution. |
| his Memorabilia, the Greek writer, Xenophon | | | | Air pollutants such as ozone, nitrogen oxides, and sulfur |
| (c.428-c.354 BC) contends that the planet earth exists | | | | dioxide also have harmful effects on vital systems. |
| for people and the climate of the earth, and the living | | | | They can kill plants and trees by destroying their |
| creatures on it, are for the benefit of humanity. | | | | leaves, and can kill animals, especially fish in highly |
| Xenophon says ‘The earth was created by a god | | | | polluted rivers. Air pollution has many disastrous |
| for people.’ His work later influenced Christianity. In | | | | effects that need to be checked and curbed |
| Rome, Cicero (106-43 BC) wrote that nature should be | | | | prudently. In order to accomplish this, scientists, |
| controlled by humans. According to him the earth | | | | environmentalists, and governments, are using or |
| was designed for humanity, as was each different | | | | testing a variety of methods aimed at reducing |
| species. | | | | pollution. There are two main types of pollution control. |
| In respect of the theory of the four elements, the | | | | Input control involves preventing a problem before it |
| Greek philosopher Aristotle (384-322 BC) added a fifth | | | | occurs, or at least limiting the effects the process will |
| one: the heavens. After breaking with Plato (429-347 | | | | produce. Five major input control methods exist. |
| BC), Aristotle thoroughly investigated the natural | | | | Output control, the opposite method, seeks to fix the |
| world. He thought that the earth could be divided into | | | | problems caused by air pollution. This usually means |
| sections defined by the amount of heat each received, | | | | cleaning up an area that has been damaged by |
| and that people could only live in the more inhabitable | | | | pollution. Input controls are usually more effective than |
| areas. Aristotle accepted the theory that underground | | | | output controls. Output controls are also more |
| wind caused volcanoes and earthquakes. He | | | | expensive, making them less desirable to tax payers |
| understood the origins of rivers and believed in a | | | | and polluting industries. Current air pollution control |
| pattern of rainfall. Teleology, which explained things in | | | | efforts are not all highly effective. In wealthier |
| terms of their purpose, was a major part of Aristotle's | | | | countries, industries are often able to shift to methods |
| theory. It caused him to heavily research | | | | that decrease air pollution. In the United States, for |
| reproduction. Aristotle's Historian Animalium details over | | | | example, air pollution control laws have been |
| 500 species, examining common characteristics | | | | successful in stopping air pollution levels from rising. |
| between the species. Throughout the ancient periods, | | | | However, in developing countries and even in countries |
| interest in botany grew because of its relation to | | | | where pollution is strictly regulated, much more needs |
| medicine. Many philosophers advanced varying | | | | to be done. |
| theories that would affect Europe in later years. | | | | Over the past years, human energy consumption has |
| Today, there are a vast number of environmental | | | | risen dramatically. The rise in use of energy |
| problems, all with unique causes and consequences. | | | | resources has meant increasing costs and the |
| Some people have said that Christianity is one of the | | | | depletion of non-renewable supplies. These and other |
| primary causes of the degradation of the environment. | | | | factors have led people to try to use energy in a more |
| Lynn White has said that the modern destruction of | | | | efficient manner. The First Law of Thermodynamics |
| the environment can be attributed to Christianity. | | | | says that energy can be transferred between forms, |
| According to White the Biblical belief that nature, seen | | | | but not created or destroyed. The Second Law of |
| as inferior to people, can be controlled by man, has | | | | Thermodynamics says that usage of heat to perform |
| brought a lack of respect for the sacredness of the | | | | work inevitably causes some heat to be lost to the |
| environment. White would also argue that Christianity is | | | | surrounding environment. As a result, perfect |
| greatly responsible for the advent of Western science | | | | efficiency in energy use is impossible. |
| and technology. Modern technology has clearly been | | | | For many things and devices that use energy, a |
| one of the main sources of environmental difficulties. | | | | maximum efficiency limit exists. A four-cycle internal |
| The Judeo-Christian notion of nature is that it is not | | | | combustion engine can achieve at most 54% |
| sacred like God. Man, however, is believed by this | | | | efficiency, while a diesel engine can reach 56%. |
| group to be made in God's image, and can therefore | | | | Steam engines only perform at 32% efficiency. In |
| shape nature as God would. There are some who | | | | reality, engines are considerably worse than this due to |
| would disagree with this application of Christianity. | | | | designs that prevent achievement of maximum |
| Those who believe in "stewardship" would say that | | | | efficiency. If one includes all devices that use energy, |
| people must respect and not destroy nature, not | | | | about 85% of energy in the US is lost due to inefficient |
| overexploit natural resources, and allow other animals | | | | usage. Many low-efficiency devices exist because |
| to live in nature as well. Many important theological | | | | when they were developed, energy costs were very |
| thinkers would agree with this version of Christianity. | | | | low. Only later, when energy costs rose, did it make |
| Calvin said that man is the steward of God's earth, | | | | sense to be more energy efficient. |
| and has no right to exploit and destroy it. Also, St. | | | | Devices that increase efficiency often are priced |
| Thomas Aquinas said that man had some responsibility | | | | higher than those that perform inefficiently. However, |
| towards animals. Christianity also favors the | | | | because less energy is used and the devices often |
| environment in some respects. To the benefit of the | | | | last longer (such as fluorescent light bulbs), the efficient |
| environment, the religion encourages caring for other | | | | devices are sometimes cheaper in the long run. |
| people, including those of the future, and some level of | | | | Governments are trying to promote efficient energy |
| respect for the environment. | | | | use for the sake of our future and their future |
| There are many different chemical substances that | | | | generations who may be deprived by us of chances |
| contribute to air pollution. These chemicals come | | | | to generate air pollutants. |
| from a variety of sources. Among the many types of | | | | |