A. Introduction Every day, the average person inhales about 20,000 liters of air. Every time we breathe, we risk inhaling dangerous chemicals that have found their way into the air. We as humans depend on the air around us to live, without it we would die. We rely on this as an essential source for living. Air pollution includes all contaminants found in the atmosphere. It is another major problem that is yet to be solved. These dangerous substances can be either in the form of gases or particles. The air is 99.9% nitrogen, oxygen, water vapor, and inert gases. Air pollution is a common term meaning the dirtying and gradual destruction of our natural resources, especially our air, water and land. This is referred to as environmental pollution. Once, years ago, the air was fresh and clear and the rivers were clean with fish swimming in the crystal clear waters and streams. This is no longer true today. Air pollution is the dirtying of the air. Where once we had blue skies and fresh air to breathe in, this is no longer the case. The air today is choked with toxic fumes from cars and factories. With more and more cars on the road, the carbon monoxide emitted from the car exhausts has polluted the Earth’s atmosphere. The clearing of land to make way for housing or farms has also lead to forests being destroyed and burnt. But did you know that air pollution also found both outdoors and indoors? It can, Pollutants can be trapped inside buildings, causing indoor pollution that lasts for a long time. The effects of air pollution are diverse and numerous. Air pollution can have serious consequences for the health of human beings, and also severely affects natural ecosystems. Because it is located in the atmosphere, air pollution is able to travel easily. As a result, air pollution is a global problem and has been the subject of global cooperation and conflict. Some areas now suffer more than others from air pollution. Cities with large numbers of automobiles or those that use great quantities of coal often suffer most severely from problems of air pollution. The first thing people see, in the morning, when they walk outside is the sky or the colored sun. Is this world giving us the privilege of seeing the natural colors of the sun through all the layers of pollution within the air? Not only are beautiful sights such as this hidden behind the pollution this world causes every day, but an increase in diseases, infections and death occurs. What are the particles in the air that can be harmful to us humans? What causes pollution? What are the effects of air pollution to the environment? What can we do to prevent it, and get rid of it?

B. Sources or Causes The sources of air pollution are both natural and human-based. As one might expect, humans have been producing increasing amounts of pollution as time has progressed, and they now account for the majority of pollutants released into the air. Ozone is not created directly, but is formed when nitrogen oxides and volatile organic compounds mix in sunlight. That is why ozone is mostly found in the summer. Nitrogen oxides come from burning gasoline, coal, or other fossil fuels. There are many types of volatile organic compounds, and they come from sources ranging from factories to trees. Carbon monoxide is released when engines burn fossil fuels. Emissions are higher when engines are not tuned properly, and when fuel is not completely burned. Cars emit a lot of the carbon monoxide found outdoors. Furnaces and heaters in the home can emit high concentrations of carbon monoxide, too, if they are not properly maintained. Nitrogen dioxide mostly comes from power plants and cars. Nitrogen dioxide is formed in two ways—when nitrogen in the fuel is burned, or when nitrogen in the air reacts with oxygen at very high temperatures. Nitrogen dioxide can also react in the atmosphere to form ozone, acid rain, and particles. Particulate matter can be divided into two types—coarse particles and fine particles. Coarse particles are formed from sources like road dust, sea spray, and construction. Fine particles are formed when fuel is burned in automobiles and power plants Sulfur dioxide mostly comes from the burning of coal or oil in power plants. It also comes from factories that make chemicals, paper, or fuel. Like nitrogen dioxide, sulfur dioxide reacts in the atmosphere to form acid rain and particles. Outside, lead comes from cars in areas where unleaded gasoline is not used. Lead can also come from power plants and other industrial sources. Inside, lead paint is an important source of lead, especially in houses where paint is peeling. Lead in old pipes can also be a source of lead in drinking water. Each toxic air pollutant comes from a slightly different source, but many are created in chemical plants or are emitted when fossil fuels are burned. Some toxic air pollutants, like asbestos and formaldehyde, can be found in building materials and can lead to indoor air problems. Many toxic air pollutants can also enter the food and water supplies. CFCs are used in air conditioners and refrigerators, since they work well as coolants. They can also be found in aerosol cans and fire extinguishers. Other stratospheric ozone depletes are used as solvents in industry. Carbon dioxide is the most important greenhouse gas. It comes from the burning of fossil fuels in cars, power plants, houses, and industry. Methane is released during the processing of fossil fuels, and also comes from natural sources like cows and rice paddies. Nitrous oxide comes from industrial sources and decaying plants.
We usually think of air pollution as being outdoors, but the air in your house or office could also be polluted. Sources of indoor pollution include * Biological contaminants like mold and pollen * Tobacco smoke * Household products and pesticides * Gases such as radon and carbon monoxide * Materials used in the building such as asbestos, formaldehyde and lead
Sick building syndrome occurs when several people are affected, but no specific source of the illness is found. Indoor air quality problems usually only cause discomfort, and most people feel better as soon as they eliminate the source of the pollution. However, some pollutants can cause diseases that show up much later, such as respiratory diseases or cancer. Making sure that your building is well-ventilated and eliminating pollutants can improve the quality of your indoor air. C. Pollutants The Clean Air Act requires EPA to set National Ambient Air Quality Standards for six common air pollutants. These commonly found air pollutants is also known as "criteria pollutants". They are particle pollution, ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead. These pollutants can harm your health and the environment, and cause property damage. Of the six pollutants, particle pollution and ground-level ozone are the most widespread health threats. EPA calls these pollutants "criteria" air pollutants because it regulates them by developing human health-based and/or environmentally-based criteria for setting permissible levels. The set of limits based on human health is called primary standards. Another set of limits intended to prevent environmental and property damage is called secondary standards. Air pollution is a real public health and environmental problem that can lead to—among other things—global warming, acid rain, and the deterioration of the ozone layer.
What are Common Air Pollutants? Ozone. A gas that can be found in two places. Near the ground (the troposphere), it is a major part of smog. The harmful ozone in the lower atmosphere should not be confused with the protective layer of ozone in the upper atmosphere (stratosphere), which screens out harmful ultraviolet rays. Carbon monoxide. A gas that comes from the burning of fossil fuels, mostly in cars. It cannot be seen or smelled. Nitrogen dioxide. A reddish-brown gas that comes from the burning of fossil fuels. It has a strong smell at high levels. Particulate matter. Solid or liquid matter that is suspended in the air. To remain in the air, particles usually must be less than 0.1-mm wide and can be as small as 0.00005 mm. Sulfur dioxide. A corrosive gas that cannot be seen or smelled at low levels but can have a “rotten egg” smell at high levels. Lead. A blue-gray metal that is very toxic and is found in a number of forms and locations. Toxic air pollutants. A large number of chemicals that are known or suspected to cause cancer. Some important pollutants in this category include arsenic, asbestos, benzene, and dioxin. Stratospheric ozone depleters.Chemicals that can destroy the ozone in the stratosphere. These chemicals include chlorofluorocarbons (CFCs), halons, and other compounds that include chlorine or bromine. Greenhouse gases. Gases that stay in the air for a long time and warm up the planet by trapping sunlight. This is called the “greenhouse effect” because the gases act like the glass in a greenhouse. Some of the important greenhouse gases are carbon dioxide, methane, and nitrous oxide. D. Effect to Environment A variety of air pollutants have known or suspected harmful effects on human health and the environment. In most areas of Europe, these pollutants are principally the products of combustion from space heating, power generation or from motor vehicle traffic. Pollutants from these sources may not only prove a problem in the immediate vicinity of these sources but can travel long distances.
Air pollution causes damage to plants and animals, affecting biodiversity and crop yields. Defra has a number of research projects investigating the effects of air pollution on vegetetation and ecosystems. Along with harming human health, air pollution can cause a variety of environmental effects: Acid rain is precipitation containing harmful amounts of nitric and sulfuric acids. These acids are formed primarily by nitrogen oxides and sulfur oxides released into the atmosphere when fossil fuels are burned. These acids fall to the Earth either as wet precipitation (rain, snow, or fog) or dry precipitation (gas and particulates). Some are carried by the wind, sometimes hundreds of miles. In the environment, acid rain damages trees and causes soils and water bodies to acidify, making the water unsuitable for some fish and other wildlife. It also speeds the decay of buildings, statues, and sculptures that are part of our national heritage. Acid rain has damaged Massachusetts lakes, ponds, rivers, and soils, leading to damaged wildlife and forests. Eutrophication is a condition in a water body where high concentrations of nutrients (such as nitrogen) stimulate blooms of algae, which in turn can cause fish kills and loss of plant and animal diversity. Although eutrophication is a natural process in the aging of lakes and some estuaries, human activities can greatly accelerate eutrophication by increasing the rate at which nutrients enter aquatic ecosystems. Air emissions of nitrogen oxides from power plants, cars, trucks, and other sources contribute to the amount of nitrogen entering aquatic ecosystems. Haze is caused when sunlight encounters tiny pollution particles in the air. Haze obscures the clarity, color, texture, and form of what we see. Some haze-causing pollutants (mostly fine particles) are directly emitted to the atmosphere by sources such as power plants, industrial facilities, trucks and automobiles, and construction activities. Others are formed when gases emitted to the air (such as sulfur dioxide and nitrogen oxides) form particles as they are carried downwind. Effects on wildlife. Toxic pollutants in the air, or deposited on soils or surface waters, can impact wildlife in a number of ways. Like humans, animals can experience health problems if they are exposed to sufficient concentrations of air toxics over time. Studies show that air toxics are contributing to birth defects, reproductive failure, and disease in animals. Persistent toxic air pollutants are of particular concern in aquatic ecosystems. These pollutants accumulate in sediments and may bio magnify in tissues of animals at the top of the food chain to concentrations many times higher than in the water or air. Particulate matter. Air pollutants can be in the form of particulate matter which can be very harmful to our health. The level of effect usually depends on the length of time of exposure, as well the kind and concentration of chemicals and particles exposed to. Short-term effects include irritation to the eyes, nose and throat, and upper respiratory infections such as bronchitis and pneumonia. Others include headaches, nausea, and allergic reactions. Short-term air pollution can aggravate the medical conditions of individuals with asthma and emphysema. Long-term health effects can include chronic respiratory disease, lung cancer, heart disease, and even damage to the brain, nerves, liver, or kidneys. Continual exposure to air pollution affects the lungs of growing children and may aggravate or complicate medical conditions in the elderly. Ozone depletion. Ozone is a gas that occurs both at ground-level and in the Earth's upper atmosphere, known as the stratosphere. At ground level, ozone is a pollutant that can harm human health. In the stratosphere, however, ozone forms a layer that protects life on earth from the sun's harmful ultraviolet (UV) rays. But this "good" ozone is gradually being destroyed by man-made chemicals referred to as ozone-depleting substances, including chlorofluorocarbons, hydrochlorofluorocarbons, and halons. These substances were formerly used and sometimes still are used in coolants, foaming agents, fire extinguishers, solvents, pesticides, and aerosol propellants. Thinning of the protective ozone layer can cause increased amounts of UV radiation to reach the Earth, which can lead to more cases of skin cancer, cataracts, and impaired immune systems. UV can also damage sensitive crops, such as soybeans, and reduce crop yields. Crop and forest damage. Air pollution can damage crops and trees in a variety of ways.Ground-level ozone can lead to reductions in agricultural crop and commercial forest yields, reduced growth and survivability of tree seedlings, and increased plant susceptibility to disease, pests and other environmental stresses (such as harsh weather). As described above, crop and forest damage can also result from acid rain and from increased UV radiation caused by ozone depletion. Global climate change. The Earth's atmosphere contains a delicate balance of naturally occurring gases that trap some of the sun's heat near the Earth's surface. This "greenhouse effect" keeps the Earth's temperature stable. Unfortunately, evidence is mounting that humans have disturbed this natural balance by producing large amounts of some of these greenhouse gases, including carbon dioxide and methane. As a result, the Earth's atmosphere appears to be trapping more of the sun's heat, causing the Earth's average temperature to rise - a phenomenon known as global warming. Many scientists believe that global warming could have significant impacts on human health, agriculture, water resources, forests, wildlife, and coastal areas. For more information, visit EPA's Global. E. Recommendation how to minimize or stop Air pollution can get worse if we do not control it today. We should remember that air is a precious commodity and without it, we would all die. To cut down on all the pollution being released into the air, we have removed the pollutant before materials are used, removed the pollutant after it is formed, or altered the process to lower pollutant levels produced. The government should enforce laws to prevent pollution from worsening. Car production should perhaps be limited and on days when the pollution level is high, car drivers should not go out in their cars but should instead use public transport. As one can surely see these types of air pollutants are harmful to our atmosphere, environment and personal health. Factory owners can help prevent all of these effects. Factories that emit toxic gases should be fined heavily so that they will be more careful after that. People who practice open burning of trash or wood should be fined heavily. Researchers have found different ways to remove these pollutants from the air. One device designed to remove hydrocarbons from the atmosphere "is an improved low pollution invisible flare burner which comprises a tall stack lined with ceramic. Primary air is introduced under pressure in a tube below and coaxial with the stack. The top of the tube contains a burner for the vented hydrocarbon gases" (Sittig 227). Within this device different air mixtures provide means for complete combustion of the vented gases with low emission of smoke and light. Another method wherein gases contaminate with vapors from volatile organic liquids are recovered by containing the vapor- containing gas in an absorbed tower with a sponge oil which absorbs the vapors. Both methods can successfully remove hydrocarbon (Sittig 348).

A method has been discovered for removing nitrogen oxides from gases. An ionizing radiation allows the noxious gas pollutants to enable a collection of the particles or mist electrostatic precipitators (Sittig 409).

In the book, How to Remove Pollutants and Toxic Materials from Air and Water, it reports: to remove sulfur oxides and particulate matter from waste gases comprises crosscurrent contacting of the waste gas stream with a moving bed or supported, copper-containing acceptor in a first zone removing in subsequent separate zones the particulate matter and the sulfur oxides from the acceptor in a subsequent zone before introducing it back into the first zone for further removal of sulfur oxides and particulate matter. Sittig 565 Another air pollutant which is able to be reduced is carbon monoxide. Factories simply have to change their coal or oil combustions to natural gas combustion. Afterburners can cause the combustion of CO. This combustion is a source of heat as in blast furnaces.

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