Air Pollution Intro • Air is the ocean we breathe. • Air supplies us with oxygen which is essential for our bodies to live. Air is 99.9% nitrogen, oxygen, water vapor and inert gases. • Human activities can release substances into the air, some of which can cause problems for humans, plants, and animals. Atmosphere structure and composition A. What is the atmosphere? 1. Outermost layer of the Earth 2.Comprised of gas, turbulently flowing, held in by gravity 3.Formed by out gassing of the Earth’s interior, since modified by many Earth system processes 4. Compared to the lithosphere and hydrosphere, the atmosphere is more rapidly changing and dynamic 5. Basic atmospheric variables a. Solar energy – sunshine is the major energy source for atmospheric and Earth surface processes b. Humidity and precipitation (moisture) c. Winds – governed by atmospheric pressure differences Composition Types of Pollution • Smog • acid rain • the greenhouse effect • "holes" in the ozone layer • Each of these problems has serious implications for our health and well- being as well as for the whole environment. Effects of Pollution • Pollutants which have an immediate effect are primary air pollutants • Those that become a problem when converted to other forms are secondary air pollutants. • Primary pollutants include carbon monoxide, radioactive wastes and highly toxic compounds such as xylenes, cyantes, and atmospheric metals. • Secondary pollutants include low level ozone which is produced by sunlight reacting with the exhaust from combustion engines. • Some pollutants are natural components of the atmosphere and become pollutants when they reach critical levels that affect life. These natural pollutants include such things as volcanic eruptions, violent storms, forest fires, wind erosion, natural gases from the decay of dead organisms, and pollen and spores. Threats to humans • The Environmental Protection Agency (EPA) has identified six primary pollutants that present a threat to human health: carbon monoxide, low level ozone, lead, the sulfur oxides, the nitrogen oxides, and particulate matter. Carbon Monoxide • Carbon Monoxide: A colorless, odorless, poisonous gas, produced by incomplete burning of carbon-based fuels including gasoline, oil and wood as well as combustion of many natural and synthetic products such as cigarettes. • When carbon monoxide gets into the body, it combines with chemicals in the blood and prevents the blood from transporting oxygen to the cells of the body. Low Level Ozone • Low Level Ozone: A variation of oxygen which contains three atoms of oxygen instead of two. • Ozone occurs in nature; it is the cause of the sharp smell you notice near a lightning strike. • Ozone is found in large concentrations in the stratosphere where it protects the earth from ultraviolet radiation. • Ground level ozone is the main component of smog, and is a product of reactions during combustion of coal, gasoline and other fuels, and also chemicals found in products including solvents, paints and hairspray. • In humans, it can cause lung tissue damage, and create high incidences of asthma and allergenic reactions. • Plants exposed to high ozone concentrations lose their chlorophyll and their food manufacturing abilities. Lead • Lead: There has been a dramatic decrease of lead in human blood levels since the element has been removed from gasoline and paints. Sources for lead in our environment, are large furnaces, incinerators, and battery plants. • Lead in the atmosphere can deposit into lakes and streams where it may be ingested by fish and eventually by humans. • The physical effects of lead poisoning are mental impairment, central nervous system damage and high blood pressure. Sulfur Dioxide • Sulfur Dioxide: A gas produced by burning coal, most notably in power plants, as well as some industrial processes such as paper production and the smelting of metals. • Sulfur dioxide plays an important role in the production of acid rain. Sulfur dioxide can cause nose and throat irritation and lung problems such as bronchitis. Nitrogen Oxide • Nitrogen Oxide: Nitrogen Oxides (NOx) are produced from burning fuels including gasoline and coal. • The major sources of NOx are power plants and transportation--vehicles that burn gasoline and diesel. • Nitrogen Oxides react with organic compounds to form smog, and are also major components of acid rain. Particulate Matter • Particulate Matter: Particulate Matter (PM) includes dust, soot and other tiny bits of solid materials that are released into and move around in the air. • U.S. health standards for air quality are based on the concentration of particles small enough to be inhaled deep into the lungs. • These are particles with a diameter of less than 10 microns. Particulates are produced by many sources, including burning of diesel fuels, incineration of garbage, mixing and application of fertilizers and pesticides, road construction and industrial processes such as steelmaking, mining operations or agricultural burning. • Particulate pollution can cause eye, nose and throat irritation and other health problems. • Fine-particulate air pollution (particles with a diameter of 2.5 microns or less) tend to deposit in the alveoli of the lungs where they remain for a long time. • Fine-particle pollution typically contains soot, acid condensates, and sulfate and nitrate particles. This type of pollution is thought to pose greater health risks not only because the particles can be breathed more deeply into the lungs, but also because they are more likely to be more toxic than larger particles. • One type of particulate pollution is the release of particles into the air from burning fuel for energy. Diesel smoke is a good example of this particulate matter . The particles are very small pieces of matter measuring about 2.5 microns or about .0001 inches. • This type of pollution is sometimes referred to as "black carbon" pollution. • The exhaust from burning fuels in automobiles, homes, and industries is a major source of pollution in the air. • Another type of particulate pollution is the release of noxious gases, such as sulfur dioxide, carbon monoxide, nitrogen oxides, and chemical vapors. These can take part in further chemical reactions once they are in the atmosphere, forming smog and acid rain. Smog • Smog is a type of large-scale outdoor pollution. • It is caused by chemical reactions between pollutants derived from different sources, primarily automobile exhaust and industrial emissions. • Cities are often centers of these types of activities, and many suffer from the effects of smog, especially during the warm months of the year. • The exact causes of pollution may be different. Depending on the geographical location, temperature, wind and weather factors, pollution is dispersed differently. However, sometimes this does not happen and the pollution can build up to dangerous levels. • A temperature inversion occurs when air close to the earth is cooler than the air above it. Under these conditions the pollution cannot rise and be dispersed. • Cities surrounded by mountains also experience trapping of pollution. • Inversion can happen in any season. Winter inversions are likely to cause particulate and or inversions are more likely to create smog. Acid Rain • Another consequence of outdoor air pollution is acid rain. When a pollutant, such as sulfuric acid combines with droplets of water in the air, the water (or snow) can become acidified . The effects of acid rain on the environment can be very serious. Acid Rain damage • Acid rain damages plants by destroying their leaves • it poisons the soil • it changes the chemistry of lakes and streams • Damage due to acid rain kills trees and harms animals, fish, and other wildlife. The Greenhouse effect • The Greenhouse Effect, also referred to as global warming, is generally believed to come from the build up of carbon dioxide gas in the atmosphere. • Carbon dioxide is produced when fuels are burned. • Plants convert carbon dioxide back to oxygen, but the release of carbon dioxide from human activities is higher than the world's plants can process. • The situation is made worse since many of the earth's forests are being removed, and plant life is being damaged by acid rain. • Thus, the amount of carbon dioxide in the air is continuing to increase. This buildup acts like a blanket and traps heat close to the surface of our earth. • Changes of even a few degrees will affect us all through changes in the climate and even the possibility that the polar ice caps may melt. Ozone • Chemicals released by our activities affect the stratosphere , one of the atmospheric layers surrounding earth. The ozone layer in the stratosphere protects the earth from harmful ultraviolet radiation from the sun. • Release of chlorofluorocarbons (CFC's) from aerosol cans, cooling systems and refrigerator equipment removes some of the ozone, causing "holes"; to open up in this layer and allowing the radiation to reach the earth. • Ultraviolet radiation is known to cause skin cancer and has damaging effects on plants and wildlife. Indoor Air pollution • Pollution also needs to be considered inside our homes, offices, and schools. • In the United States, we spend about 80-90% of our time inside buildings, and so our exposure to harmful indoor pollutants can be serious. Sources of indoor pollution • There are many sources of indoor air pollution. Tobacco smoke, cooking and heating appliances, and vapors from building materials, paints, furniture, etc. cause pollution inside buildings. • Radon is a natural radioactive gas released from the earth, and it can be found concentrated in basements in some parts of the United States. • Pollution exposure at home and work is often greater than outdoors. • The California Air Resources Board estimates that indoor air pollutant levels are 25-62% greater than outside levels and can pose serious health problems. Radon • Radon-222 is a radioactive gas released during the natural decay of thorium and uranium, which are common, naturally occurring elements found in varying amounts in rock and soil. Odorless, invisible, and without taste, radon cannot be detected with the human senses. • Radon-222 decays into radioactive elements, two of which -- polonium-218 and polonium-214 -- emit alpha particles, which are highly effective in damaging lung tissues. These alpha-emitting radon decay products have been implicated in a causal relationship with lung cancer in humans. Characteristics and Sources of Radon • Outdoors, where it is diluted radon poses significantly less risk than indoors. • In the indoor air environment, the magnitude of radon concentration indoors depends primarily on a building's construction and the amount of radon in the underlying soil. • The soil composition under and around a house affects radon levels and the ease with which radon migrates toward a house. • Normal pressure differences between the house and the soil can create a slight vacuum in the home that can draw radon gas from the soil into the building. • Radon gas can enter a home from the soil through cracks in concrete floors and walls, floor drains, sump pumps, construction joints, and tiny cracks or pores in hollow-block walls. • Radon levels are generally highest in basements and ground floor rooms that are in contact with the soil. • Factors such as the design, construction, and ventilation of the home affect the pathways and sources that can draw radon indoors. • Another source of radon indoors may be air released by well water during showering and other household activities. Mold • Molds produce tiny spores to reproduce. Mold spores waft through the indoor and outdoor air continually. • When mold spores land on a damp spot indoors, they may begin growing and digesting whatever they are growing on in order to survive. • There are molds that can grow on wood, paper, carpet, and foods. • The key to mold control is moisture control. It is important to dry water damaged areas and items within 24-48 hours to prevent mold growth. • Clean up the mold and get rid of the excess water or moisture. Fix leaky plumbing or other sources of water. Wash mold off hard surfaces with detergent and water, and dry completely. Absorbent materials (such as ceiling tiles & carpet) that become moldy may have to be replaced. Noise pollution • Although noise is a significant environmental problem, it is often difficult to quantify associated costs. An OECD report on the social costs of land transport identified four categories of impact from transport noise: • productivity losses due to poor concentration, communication difficulties or fatigue due to insufficient rest • health care costs to rectify loss of sleep, hearing problems or stress • lowered property values • loss of psychological well-being. effects Healthaffect our health in • Air pollution can many ways with both short-term and long-term effects. • Different groups of individuals are affected by air pollution in different ways. • Some individuals are much more sensitive to pollutants than are others. Young children and elderly people often suffer more from the effects of air pollution. • People with health problems such as asthma, heart and lung disease may also suffer more when the air is polluted. • The extent to which an individual is harmed by air pollution usually depends on the total exposure to the damaging chemicals. • Short-term effects include irritation to the eyes, nose and throat, and upper respiratory infections such as bronchitis and pneumonia. Other symptoms can include headaches, nausea, and allergic reactions. • Short-term air pollution can aggravate the medical conditions of individuals with asthma and emphysema. In the great "Smog Disaster" in London in 1952, four thousand people died in a few days due to the high concentrations of pollution. • 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.
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