Air Pollution-Chapters 18 and 19

Buffer (2)

A compound that reacts with and neutralizes the acid contained in acid rain (480). Areas that have soils rich in buffers are able to withstand higher amounts of acid rain than are areas with less buffer content in their soils. Many areas where acid rain has been a problem for many years have less buffering capacity now, as the continual exposure to acid has lessened its buffering abilities. An example of a buffer that helps neutralize acid rain is calcium carbonate.

pH (1)

A measure of acidity based on the concentration of OH- ions within a particular solution (37). pH is how rainwater is tested to determine if it is acidic or not. A substance with a pH less than 7 is acidic, and a pH greater than 7 is basic. Precipitation with a pH of 5 or lower is considered "acid rain" which occurred due to air pollution. Natural unpolluted rainwater has a pH of about 5.6 because of carbon dioxide in the air which reacts with water vapor to naturally form carbonic acid.

Photochemical Smog (1)

A mixture of pollutants formed under influence of radiation, light, and heat from the sun (477). It is generally formed when large amounts of nitric oxides and volatile organic chemicals are released into the air. NO mixes with oxygen in the atmosphere to form NO2, and when combined with volatile organic chemicals and hit by radiation form sunlight, produces ground level ozone, nitric acid, aldehydes, peroxyacyl nitrates, and other secondary pollutants that collectively form photochemical smog. Hotter days lead to higher levels of photochemical smog and is more common in sunny areas with a lot of traffic. Examples of areas with high photochemical smog include Los Angeles, Denver, Salt Lake City, Mexico City, Sydney, Buenos Aires, and Bangkok. This causes difficulties seeing (and probably more car accidents), and also causes respiratory and eye irritation.

Industrial Smog (1)

A mixture of smoke and fog in cities where large amounts of coal were burned for both industrial and residential purposes that consisted of sulfur dioxide, droplets of sulfuric acid, and other solid particulates (476). Industrial Smog is formed from the carbon monoxide and carbon dioxide produced from burning coal mixing with the sulfur dioxide (formed from sulfur particles reacting with air particles), sulfuric acid (formed from mixing sulfur dioxide with water particles), and ammonium sulfate (formed from mixing sulfuric acid with ammonia in the air), giving smog its gray color. In the 1960's-1970's, industrial smog was a large problem in cities like London, Chicago, and Pittsburgh, where industry was growing faster than the rate at which pollution controls could be safely set. Today, controls on pollution such as tall smokestacks and large boilers help control pollution in these areas and prevent smog. However, areas like China have huge pollution problems and must make changes in order to reduce the amount of industrial smog they produce.

Smog (1)

A mixture of smoke and fog which forms in areas with high amounts of air pollution. It is a thick form of fog that is gray, dense, and inhibits both vision and breathing (471). Smog causes many problems, such as respiratory illnesses, weakening of the immune system, inhibition of vision (sometimes people could not see their own feet walking on the street!), and even death from the deadly chemicals trapped within the air. Smog is seen today in highly industrialized areas with weak air pollution legislation, such as China. In these areas, streets and even mountains are covered by a haze of smog.

Ozlone Layer (1)

A portion of the stratosphere that contains a highly concentrated amount of O3 (ozone) (470). The ozone layer is important because it is able to block out 95% of the radiation from the sun. Without the ozone layer, there would not be able to have any life on land because the UV radiation would cause cancer, sunburn, and damage to immune systems for the land organisms.

Acid Rain (1)

A specific type of wet acid deposition, where acidic particles such as sulfuric acid or nitric acid fall to the Earth in rain, snow, or fog (479). Due to large coal burning power plants and pollution-emitting cars, the United States has rain that is extremely acidic, up to 10 times more acidic than natural precipitation. Acid rain is damaging to crops, whose roots are not able to withstand the increased acidity from the rainwater and thus die or are unable to reproduce. Acid rain also damages aquatic ecosystem by killing fish unable to survive in acidic environments.

H2CO3 (2)

Carbonic acid. This compound is naturally formed in unpolluted rain when carbon dioxide (CO2) reacts with water vapor in the air (479). The presence of carbonic acid naturally occurring due to the reaction between carbon dioxide and water vapor is why unpolluted rainwater has a natural acidity less than a pH of 7. This is why even unpolluted rainwater is somewhat acidic. Increased CO2 emissions however can create increased acidity, because more CO2 in the air creates more carbonic acid in the rainwater, increasing rain acidity.

CFC (1)

Chloroflourocarbon. Chemicals developed in 1930s known as Freons that are chemically un-reactive, odorless, non-flammable, non-toxic, non-corrosive, and inexpensive that were used as coolants, electronic cleaners, insulation fillers, and fumigants (524). CFCs are persistent chemicals that destroy ozone in the stratosphere. It is estimated that 75-85% of ozone depletion is due to the release of CFCs into the atmosphere. CFCs break down due to radiation when they reach the stratosphere, releasing chlorine, flourine, and bromine atoms, which then break down O3 atoms into O2 and O atoms. The O atom bonds to a chlorine/ flourine/ bromine, which is released when another oxygen bonds to the oxygen atom, releasing the highly electronegative chlorine/ flourine / bromine, thus furthering the cycle. These CFCs can last in the stratosphere for 300+ years, making them very damaging to the ozone layer and powerful ozone depletion agents.

SOx Gases (Sulfur Oxides)

Gases formed from mixtures of sulfur pollutants reacting with oxygen and water particles in the atmosphere (473). Examples of these gases include sulfur dioxide (SO2) which is a naturally occuring colorless gas that comes from the burning of coal and smelting of ores. Sulfuric Acid and sulfate particulates are also examples of SOx gases, andare major components of acid rain and acid deposition. These gases reduce visibility, make breathing problems such as asthma worse, damage plant and soil life, corrode metals and damage states and stone work, and destroy aquatic life.

Primary Pollutant (3)

Harmful chemicals that are emitted directly from into the air and could be from either natural or human sources (471). Examples of primary pollutants include a carbon dioxide, carbon monoxide, sulfur dioxide, nitrogen oxide, nitrogen dioxide, most hydrocarbons, and most suspended particles (smoke).

Ozone (1)

O3, a component of the ozone layer. It is formed when radiation from the sun comes in contact with oxygen in the air. It is a colorless, highly reactive gas and a component of photochemical smog (470) (474). Ozone is important because it is the global sunscreen that keeps out radiation and makes up the ozone layer. It is also important because the ozone layer prevents all of the oxygen in the lower atmosphere from becoming ozone as well which would hinder life to survive. It is also a pollutant that causes breathing problems and aggravates lung diseases, reduces resistance of the immune system, and damages plants. It is considered "bad ozone" if it is in the troposphere because it can harm human life in the troposphere, whereas the "good" ozone in the stratosphere protects human life from excess radiation. Human pollution has decreased the ozone in the stratosphere and increased the ozone in the troposphere.

PANs (3)

Peroxyacyl Nitrates. These are part of the mixture of chemicals that form as secondary pollutants. (477). PANs are photochemical oxidants that oxidize certain chemicals in the atmosphere and in lungs, causing health problems. They are also a part of photochemical smog, which impedes vision and can cause breathing difficulties in sunny areas with a lot of traffic.

H2SO4 (2)

Sulfuric Acid formed when sulfur dioxide is converted into aerosols by reacting with water particles in the air (473) This acid then falls in droplets as acid rain, damaging crop life, aquatic ecosystems, and causing a higher soil and rainfall pH than can be supported in an ecosystem.

Troposphere (1)

The atmospheric layer that is closest to the earth's surface which extends from 11 miles above the sea level to 5 miles above the earth (469). The troposphere contains all of the air that we breathe as well as all of the pollution that we put into it. This is the most important layer of the atmosphere studied in environmental science because it is the layer used by life to breathe. It is responsible for chemical and weather cycling on the planet.

Atmospheric Pressure (3)

The force per unit area of a certain column of air that is exerted on whatever is around it (469). Atmospheric pressure decreases as the height (altitude) increases, because there is a lower air particle density at higher altitudes, leading to less collisions of particles in the same area of space, leading to a lower atmospheric pressure.

Stratosphere (1)

The layer of the Earth above the troposphere that extends from 11 to 30 miles above the surface of the Earth (470). This layer is important because it contains the layer of atmosphere known as ozone, which is a vital atmospheric layer enabling all life to occur on land, as it blocks the rays of radiation from the sun.

Mesosphere (3)

The layer of the atmosphere that is above the troposphere and is significantly colder (470).

Acid Deposition (1)

The mixture of acidic particles in either wet or dry deposition, which includes rain, snow, fog, or acidic particulate matter itself (479). Acid deposition can be wet or dry. Wet acid deposition occurs when particulate matter mixes in with a water source or with cloud vapor, and then falls to the earth as snow, rain, or fog, and generally can happen up to two weeks later in areas far from an emission site. Dry acid deposition is when acidic particles themselves occurs near emission sources and generally near an emission source. Acid deposition causes harm in several ways. It causes many health problems (such as respiratory illnesses), can destroy architecture, decreases visibility, leaches heavy metals into soils and drinking water and build up in organisms which we eat through bioaccumulation, harms aquatic ecosystems through increased acidity and the release of aluminum ions deadly to fish, harms crops and reduces plant productivity, weakens trees, and has hindered tree growth in general. Acid deposition can be reduced by preventing the emissions of sulfur dioxide, nitrogen oxides, and particulates into the atmosphere through reducing coal use, increasing renewable energy resource use, removing SOx and NOx particulates from smokestack gases, and improving energy efficiency. Acid deposition can also be cleaned up by using limestone to neutralize acidified areas, and by adding phosphate fertilizer to neutralize acidified lakes.

Air Pollution (1)

The presence of chemicals in the atmosphere at levels high enough that they cause harm to other organisms (including humans) (470). Air pollution can occur through natural and human sources. Natural sources include volcanoes and forest fires, while human sources include fossil fuel burning plants and cars. Human sources are mostly seen in urban industrialized areas and have been steadily increasing since the industrial age. Air pollution is important because it can deplete the ozone layer, be harmful for human health, and are a major cause of global warming.

Ozone Depletion (1)

The thinning of the concentration of ozone in the stratosphere (523) Measurements show that this thinning has occurred over the antarctic, the arctic, and these masses of ozone depleted air move to Australia, New Zealand, and South Africa. Scientists have determined that this ozone depletion is a major threat to all forms of life on land on Earth, as the ozone layer is necessary in order for life to survive the sun's radiation. Ozone depletion could cause humans to develop skin cancer and worse skin cancers, would reduce yields for crops and reduce forest productivity, would decrease certian populations of aquatic species, increase smog, and increase acid deposition. Most importantly, ozone depletion could kill off phytoplankton, which are not only majorly important to their aquatic ecosystems, but also are vital in converting CO2 to O2. Losing this species would accelerate global warming enormously.

NOx Gases (Nitrogen Oxides)

These gases are formed when nitrogen reacts with oxygen in the air at a high termperature (like in car engines or powerplants) (473). These gases include nitric oxide (NO), nitric acid (HNO3), nitrous oxide (N20) and nitrate salts (HNO3). These gases are important because they can cause irritation to eyes nose and mouth, irritate asthma and make it difficult to breathe, create petrochemical smog, cause acid deposition, suppress plant growth, and reduce visibility.

Secondary Pollutants (3)

When primary pollutants in the air combine and react to form other harmful chemical compounds (471). Examples of secondary pollutants are hydrogen peroxide, ozone, most nitrate and sulfate salts, PANs, SO3, nitric acid, and sulfuric acid.