Enviro Unit 6
Describe the basic chemical reactions for natural stratospheric ozone formation and destruction.
Formation: 1. In the first step, UVC radiation breaks diatomic oxygen in two oxygen molecules. This happens to only a few oxygen molecules at any given time. O2 + UV-C --------> O + O 2. A free oxygen atom produced in the first reaction encounters and oxygen molecule and they form ozone O + O2 ---------> O3 3. Both UVB and UVC radiation can break a bond in this new ozone molecule, forming molecular oxygen and a free oxygen atom once again Destruction: O3 + UV-B or UV-C ------> O2 + O Thus the formation of ozone in the presence of sunlight and its subsequent breakdown is a cycle that can occur indefinitely as long as there is UV energy entering the atmosphere.
Industrial chemicals
Lead - Neurotoxin Source: paint, gasoline Impact: Impaired learning, nervous system disorders, death Mercury- Neurotoxin Source: coal burning, fish consumption Impact: Damaged brain, kidneys, liver and immune system Arsenic - Carcinogen Source: mining, groundwater Impact: Cancer Asbestos- Carcinogen Source: Building materials Impact: Impaired breathing, lung cancer PCB's - Carcinogen Source: Industry Impact: Cancer, impaired learning, liver damage Radon- Carcinogen Source: Soil, water Impact: Lung cancer Alcohol- teratogen Source: Alcoholic beverages Impact: Reduced fetal growth, brain and nervous system damage DDT- Endocrine disruptor Source: Insecticide Impact: Feminization of males, thin eggshells of birds
Describe the effect of urban noise pollution (i.e., transportation, construction, and domestic and industrial activity) on humans and on animals in ecological systems.
Noise pollution: a sound at levels high enough to cause psychological stress and hearing loss. Effects: - Human hearing can be damaged with sudden or prolonged exposure to noises above 83 DBAs - so hearing loss - Stress, depression, anxiety, high blood pressure, heart disease. - Causes animals in ecosystems to have stress which leads to reduced reproduction, decline in overall health, and disrupted communication. - Noise causes the masking of sounds used to communicate or hunt, damaging hearing, and causing changes to migratory roots to animals.
Scrubbers
Removes PM by using a combination of water and air that actually separates and removes particles. Particles are removed in the scrubber in a liquid or sludge form and clean gas exits. Like the electrostatic precipitators, particles are sometimes ionized before entering the scrubber to increase its efficiency. Scrubbers also remove sulfur dioxide.
Identify at least three major routes of exposure to environmental contaminants.
Routes of exposure: The way in which an individual might come into contact with an environmental hazard, such as a chemical. Water- drinking, bathing, or swimming Food Air- pollutants from burning fuels Soil Fetuses/babies Most chemicals have a limited number of major routes
Define sick building syndrome and at least two causes of this phenomenon.
Sick building syndrome: A buildup of toxic pollutants in an airtight space, seen in newer buildings, in developed countries, in the temperate zone. Causes: 1. Inadequate or faulty ventilation 2. Chemical contamination from indoor sources such as glues, carpeting, furniture, cleaning agents 3. Chemical contamination in the building from outdoor sources such as vehicle exhaust transferred through building air intakes 4. Biological contamination from inside or outside such as molds or pollen Health effects: Headaches, nausea, throat or eye irritation, coughing and sneezing
Vapor Recovery Nozzles
pollution control device Vapor recovery nozzles are used at the gas pump to help reduce air pollution. They capture the gasoline vapors (VOCs and benzene) that escape from automobile tanks when they are being refueled. The vapors are returned to the underground gasoline storage tank through special hoses and pipes.
Range of tolerance
the limits to the abiotic conditions that a species can tolerate - salinity - PH - oxygen availbility - temp
Indoor Air Pollution > Health Impacts
~3 billion people cook and heat their homes using solid fuels (wood, crop wastes, charcoal, coal and dung (*Biomass!) Inefficient cooking technologies and solid fuels produce small soot particles - Penetrate deep into lungs, leading to pneumonia, stroke, heart and lung disease - 4 million people die every year from illnesses caused by pollutants due to cooking with solid fuels Approximately half the world cooks their everyday meals over open fires, resulting in high pollutant exposure. Because women are primarily doing the cooking, they are also the most at risk for this exposure. From using cookstoves, the pollutants of concern are particulate matter, carbon monoxide and VOCs.
Distinguish between the "innocent-until-proven guilty" principle and the precautionary principle.
"innocent-until-proven guilty" (US uses) principle: A principle based on the belief that a potential Hazard could not be considered an actual hazard until the scientific data definitively demonstrates that it actually causes harm. - Allows beneficial chemicals to be sold sooner. However, harmful chemicals can affect humans or Wildlife for decades before sufficient scientific evidence accumulates to confirm that they are harmful. Precautionary principle: A principle based on the belief that action should be taken against a plausible environmental hazard. - The plausibility of the risk cannot be speculation, it must have a scientific basis. This approach allows fewer harmful chemicals to enter the environment. - The slower pace of the slower pace of approval can reduce the financial motivation of manufacturers to invest in research for new chemicals.
Explain why air pollution poses a greater health risk to children.
Air pollution poses a greater health risk to children because: - Children have an underdeveloped or less developed immune systems leading to a greater risk of illness following exposure - Children have a lower body mass leading to a higher relative dose of air pollution - Children spend more time indoors with their mothers leading to higher exposure to air pollution - Children have smaller respiratory systems, narrow airways, so mild inflammation may cause more severe respiratory distress.
Identify technological solutions to reduce exposure to indoor air pollution.
- Use more efficient cooking stoves, ventilate cooking areas, cook outside whenever possible, and change customs and practices that will reduce their exposure to indoor air pollution. - The use of an efficient cook stove will have the added benefit of consuming less fuel. This improves air quality and reduces the amount of fuel needed, which reduces the amount of nearby vegetation that must be collected and also reduces the amount of time that a woman must spend searching for fuel. - One method of ensuring a cleaner burn is the use of a small fan to facilitate greater oxygen delivery. However, if someone doesn't have access to electricity some sort of internal source of energy for the fan is needed. - BioLite home stove, physically separates the solid fuel from the gasses that form when the fuel is burned, which allows the stove to burn the gasses. In addition a small electric fan, located inside the stove harnesses energy from the heat of the fire and moves air through the stove at a rate that ensures complete combustion. the result is a more efficient burn, less Fuel use, and less release of carbon monoxide and particulate matter.
Describe two realistic strategies for addressing or mitigating noise pollution
1. Regulate noise production/exposure. For example the US Noise Control Act of 1972 allows the EPA to regulate noise and set emissions standards for sources of noise. 2. Reduce the amount of noise pollution occuring near habitats so it has a lesser effect on the animals.
epidemic vs pandemic
An epidemic is a large-scale outbreak of an infectious disease in an area or country while a pandemic is a global epidemic. Epidemic EXP: A fast-acting strain of influenza claimed the lives of four hundred people in western Ohio.
Describe anthropogenic ozone depletion and mitigation strategies.
Anthropogenic ozone depletion: Chlorofluorocarbons, or CFC were considered essential to Modern Life and considered safe because they were non-toxic and nonflammable. It turned out that these chemicals had adverse effects in the stratosphere. 1. CFC's introduce chlorine into the stratosphere. when chlorine is present, it can attach to an oxygen atom in an ozone molecule thereby Breaking the Bond between that atom and the molecule and forming chlorine monoxide and O2 O3 + Cl ------> ClO + O2 2. Subsequently, the chlorine monoxide molecule reacts with a free oxygen atom, which pulls the oxygen from the chlorine monoxide to produce free chlorine again. ClO + O ----> Cl + O2 Chlorine starts up and ends up as a free atom. however an ozone molecule and a free oxygen atom are converted into two oxygen molecules. The ozone molecules are no longer available to absorb incoming UVB and UVA radiation. Mitigation Strategies: - 24 nations in 1987 signed the Montreal protocol on substances that deplete the ozone layer. This was a commitment to reduce CFC production by 50% by the year 2000. It was the most far-reaching environmental treaty to date in which global CFC exporters prioritize the protection of the global biosphere over their short-term economic self-interest. - The chlorine concentration reduction process is slow because CFCs are not easily removed from the stratosphere.
Describe the effects of acid deposition on aquatic organisms
Aquatic ecosystems: - Lower pH of lakes and streams (less than 5) causes decreased species diversity of aquatic organisms. Many species are able to survive and reproduce only within a narrow range of environmental conditions. When the lake acidifies the pH lowers and some organisms will begin to have developmental or reproductive problems. - Trace metals such as aluminum, mercury, manganese and cadmium, which are leached from sediment and rocks by the increased acidity, are toxic to life. Thus, the pH does not have to decrease very much before fish kills can occur (less food for birds/mammals too). - Acidification also interrupts normal decomposition of dead plant and animal material in lakes and streams because many of the bacteria that assist in decomposition perish. Without the usual decomposition processes, dead material settles to the bottom, making the water look crystal clear.
Describe these major indoor air pollutants including sources and human health effects: asbestos, carbon monoxide, dust, lead, mold, radon, VOCs
Asbestos- tiny tiny shards of glass Sources: Used as an insulator on steam and hot water pipes and in shingles for the siding of buildings. Health Effects: Respiratory Diseases such as asbestosis and lung cancers. When insulating materials become old or damaged the fine fibers can become airborne and can enter the respiratory tract. Carbon monoxide Sources: Occurs as a result of malfunctioning exhaust systems on household furnace heating systems, most commonly natural gas heaters. When the exhaust system malfunctions, exhaust air escapes into the living space of the house. This gas is colorless and odorless making it very dangerous. Health Effects: In the body carbon monoxide binds with hemoglobin more efficiently than oxygen thereby interfering with oxygen transport in the blood. Extended exposure to high concentrations of carbon monoxide in air can lead to oxygen deprivation in the brain and ultimately death. Dust Sources: Natural sources. Can contain particulates of different sizes. Home heating and cooling systems should be changed often to prevent dust formation. Human Health Effects: Can irritate eyes and breathing. Lead Sources: Old paint found in homes built before 1978. If paint is chipped or deteriorating, paint can create dust, chips and suspended particles that can be inhaled. Human Health Effects: Can adversely affect the nervous system, kidney function, immune system, reproductive and developmental systems, and the cardiovascular system Mold: Sources: Natural source. Can be found in homes, schools, and buildings with poor ventilation. Water leaks and too much humidity can create perfect conditions for mold to grow undetected. Human Health Effects: Infects respiratory passageways. Cause irritation in eyes, nose, nasal passageway Radon Sources: Radon-222 is the most common form in the environment, and it is a member of the radioactive decay chain of uranium-238. Uranium is commonly found in rocks and soil, especially those with high concentrations of granite.Radon can seep into a home through cracks in the foundation, or from underlying rock, soil, or groundwater. Health Effects: Either the radon or the polonium can attach to dust and other particles in the air and then be inhaled by the inhabitants of the home. 21,000 people die each year from radon induced lung cancer making radon the second leading cause of lung cancer. VOCs Sources: Many VOCs are used in building materials, furniture, furniture, and other home products such as glue and paint. One of the most toxic of these compounds is formaldehyde, which is used widely to manufacture a variety of building products such as particle board and carpeting glue. Human Health Effects: a high enough concentrationIn a confIn a confined space can cause a burning sensation in the eyes and throat and breathing difficulties and Asthma in some people.
Distinguish between bioaccumulation and biomagnification and their effects on ecosystems.
Bioaccumulation: An increased concentration of a chemical with an organism/individual over time. The process of bioaccumulation begins when an individual is exposed to small amounts of a chemical from the environment and incorporates the chemical into its tissues, typically its fat tissues. Effects on ecosystems: Negatively impacts the environment because chemicals are building up and becoming toxic in these animals causing them to die. Biomagnification: The increase in chemical concentration in animal tissues as the chemical moves up the food chain. The original concentration in the environment is magnified to occur at a much higher concentration in the top predator of the community. Effects on ecosystems: Chemicals and toxins move more rapidly and dangerously throughout the environment, killing/harming animals as they do.
Gasses
Carbon dioxide (CO2) Cellular respiration, complete combustion Nitrogen dioxide (NO2) High temp. combustion Volatile organic compounds (VOCs) Incomplete combustion, volatiles such as cleaning products, paint, etc. Carbon Monoxide (CO) Incomplete combustion, photochemical reactions in the atmosphere O2 + CO + sunlight → O3 + CO2 (greenhouse gas formation) PM10 (< 10 µm) Ex., pollen, heavy dust, ash PM2.5 (< 2.5 µm) Ex., Dust, bacteria, mold spores PM1 (< 1 µm) Ex., tobacco smoke, smog, soot, viruses Health Impacts: All PM 10 microns or smaller can be inhaled PM10 irritates the eyes, nose, and throat PM2.5 and PM1 can enter the bloodstream through the alveoli
Distinguish between natural (if applicable) and anthropogenic sources for the pollutants listed above.
Carbon monoxide (CO) Natural: Volcanoes, bushfires, methane oxidation Anthro: - Incomplete burning of carbon-based fuels (biomass, fossil fuels, cars, power plants), smoking Nitrogen Oxides (NOx) Natural: - Forest fires - Lightning - Microbial activity in soils Anthro: - All combustion in the atmosphere including fossil fuel combustion, wood, and other biomass burning. Sulfur Oxides (SOx) Natural: - Volcanic eruptions - Forest Fires Anthro: - Combustion of fuels that contain sulfur, including coal, oil, and gasoline Part. Matter (PM) Natural: - Volcanic eruptions - Dust Storms - Wood fires Anthro: - Combustion of coal, oil, and diesel, and of biofuels such as manure or wood - Agriculture, road construction, and other activities that mobilize soil, soot, and dust. Ozone (O3) Natural: - Formed by the combination of sunlight, water, oxygen, VOCs, and NOx Lead (Pb) Anthro: Gasoline additive, oil and gasoline, coal, old paint Mercury (Hg) Anthro: Coal, oil, gold mining Volatile Organic Compounds (VOCs) Natural: Evaporations of fuels, solvents, paints Anthro: Improper combustion of fuels such as gasoline Carbon dioxide (CO2) Natural: released during respiration Anthro: Combustion of fossil fuels and clearing of land DRIVING CARS is biggest anthro source!
Identify and describe the ecosystem and human health effects of the nine major air pollutants in the troposphere
Carbon monoxide (CO)- Vehicles largest source Health: Binds with hemoglobin 200x faster than oxygen, Heart & lung disease Enviro: Global warming (greenhouse gas) Nitrogen Oxides (NOx)- Vehicles largest source Health: Respiratory irritant, increases susceptibility to respiratory infection. Enviro: - Ozone precursor leads to formation of photochemical smog. - Converts to nitric acid in the atmosphere which is harmful to aquatic life and some vegetation. - Contributes to over-fertilization of terrestrial and aquatic systems. Sulfur Oxides (SOx)- power plants that generate electricity with coal Health: Respiratory irritants can exacerbate asthma and other respiratory ailments. Enviro: - Gas can harm stomata and other plant tissue - Converts to sulfuric acid in the atmosphere which is harmful to aquatic life and some vegetation. Part. Matter (PM)- fires main source Health: - Can exacerbate respiratory and cardiovascular disease and reduce lung function - Causes headaches at low concentrations - Can cause death with prolonged exposure at high concentrations Enviro: - Since it can scatter and absorb sunlight, it has the possibility of reducing photosynthesis. Ozone (O3) Health: Reduces lung function and exacerbated respiratory systems Enviro: - Degrades plant surfaces - Damages materials such as rubber and plastic Lead (Pb) Health: - Impairs central nervous system - At low concentrations, can have measurable effects on learning and ability to concentrate Enviro: - Interferes with the photosynthesis by reducing the amount of carbon dioxide the plants can process and release as oxygen. Mercury (Hg) Health: Impairs central nervous system Enviro: Bioaccumulates in the food chain Volatile Organic Compounds (VOCs) Enviro: A precursor to ozone formation Carbon dioxide (CO2) Health: - Can cause headaches, fainting, difficulty breathing. Enviro: - increases greenhouse gas concentrations
Describe chemical persistence and the factors that affect persistence. Discuss the concerns associated with POPs.
Chemical Persistence: The length of a time a chemical remains in the environment. Factors that affect: Depends on a number of factors including temperature, ph, whether the chemical is in water or soil, and whether it can be degraded by sunlight or broken down by microbes. Concerns with POPs: POPs are persistent organic pollutants and they are carbon based molecules that break down very slowly in the environment. Chemicals when they persist for many years, can cause even greater harmful effects on humans and other organisms. POPs in the gas phase can move very long distances from their source. POPs are fat soluble and can bioaccumulate within the fatty tissues of organisms. Causes birdshell egg thinning.
Global Distillation Effect
Colder climates favor the deposition of pollutants; often far from point of release Dispersal of Persistent Organic Pollutants (POPs)
Aside from technological solutions, identify two other air pollution control strategies.
Creating a market for Sulfur Emissions: A provision for the buying and selling of allowances that authorized the owner to release a certain quantity of sulfur. sulfur allowances are awarded annually. Part of the Clean Air Act. Using fuels that contain fewer impurities; coal and oil Occur naturally with different sulfur concentrations and are available for purchase at a variety of sulfur concentrations. Low sulfur concentrated fuels are more expensive however.
Explain why ozone concentrations (tropospheric) vary throughout the day. Discuss when concentrations are highest (daily and seasonally)?
DAY= more sunlight so more ozone 1) Sunlight causes Nitrogen dioxide to break apart into nitrogen oxide and a free oxygen atom. 2) The free oxygen atom with diatomic oxygen to form ozone. However, because VOCs have combined with nitrogen oxide in a strong bond, nitrogen oxide is no longer available to combine with ozone. 3) Since the nitrogen oxide is not available to break down ozone by recombining with it, a larger amount of ozone accumulates. This explains the daytime accumulation of ozone and urban areas with an abundance of both vocs and nitrogen dioxide. (Many of the chemical reaction that form ozone proceed more rapidly at higher temperatures) NIGHT: When sunlight intensity decreases and nitrogen oxide is still present in the atmosphere, the ozone combines with nitrogen oxide and reforms into O2 + NO2. This is referred to as ozone destruction and it is a natural process that happens in the latter part of the day and evening. Overall concentrations of ozone are higher during the day/summers and lower during the night/winters.
Explain how indoor air pollution differs in developing and developed countries
Developing: Countries that use wood, animal manure, or coal indoors for heat and cooking are at greater risk. Biomass and coal are usually burned in open pit fires that lack the proper mix of fuel and air to allow complete combustion (carbon monoxide). Usually, there is no exhaust system and little or no ventilation available in the home, which makes indoor air pollution from carbon monoxide and particulates a particular hazard in developing countries. Exposure to indoor air pollution from cooking and heating increases the risk of acute respiratory infections, pneumonia, bronchitis, and even cancer. More than 90% of deaths attributable to indoor air pollution occur in developing countries. Developed: People in much of the developed world have begun to spend more time indoors. Although improved insulation and tightly sealed building envelopes reduce energy consumption, these tightly sealed buildings also keep existing air in contact with the inhabitants of homes, schools, and offices for greater amounts of time. An increasing number of materials in the home and office are made from plastics and other petroleum-based materials that can give off chemical vapors. All of these factors combine to allow many possible sources of indoor air pollution to impact occupants. - Household products; pesticides; paints; cleaning fluids--------> VOCs and others - Fireplaces; wood stoves --------> PM - Leaky/unvented gas/wood stoves/furnaces;car left running in garage-> Carbon Monoxide - Floor/ceiling tiles, pipe insulation ----> Asbestos - Rocks and soil beneath house ----> Radon
Explain how scientists use dose-response studies to determine harmful concentrations of chemicals.
Dose-response studies: A study that exposes organisms to different amounts of a chemical and then observes a variety of possible responses, including mortality or changes in behavior or reproduction. These studies expose animals to different amounts of a chemical and then look for a variety of possible responses. the concentration of the chemicals being considered can be measured in air, water, or food. Dose response studies most commonly measure mortality as a response. At the end of a dose response experiment, scientists count how many individuals die after exposure to each concentration. As the concentrations of the chemical increase more individuals begin to die.
Summarize the major effects of ozone depletion
Ecological Impacts: Exposure to UVB is also harmful to the cells of plants, and it reduces their ability to convert sunlight into usable energy. Agricultural Impacts: Exposure to this UV radiation is bad for crops and they will not be able to gain the right energy from the sun to reproduce. Human Health Effects: UV radiation of all types can damage the tissue and DNA of living organisms. exposure to UVB radiation increases the risk of skin cancer and contracts and suppresses the immune system in humans.
Describe how acid deposition forms, including the sources of the pollutants that lead to acid deposition. Discuss why acid deposition may affect regions far from the source of pollutants. Explain why rain is "naturally" slightly acidic.
Formation: 1) Nitrogen oxides (NOx) and sulfur dioxide (SO2) are released into the atmosphere by natural (volcanoes) and anthropogenic combustion processes. 2) Through a series of reactions with atmospheric oxygen and water, these primary pollutants are transformed into secondary pollutants nitric acid (HNO3) and sulfuric acid (H2SO2). 3) These ladder compounds break down further producing nitrate, sulfate and hydrogen ions that generate the acidity in acid deposition. Spread: Acid deposition can affect regions far from the source of pollutants because although these transformations occur over a number of days, during this time, the pollutants can travel 600 miles or more. Eventually the secondary acidifying pollutants are washed out of the air and deposited either as precipitation or in dry form on vegetation, soil, or water. Could be in form snow, rain, fog, sea salts, or wind RAIN: All rain is naturally somewhat acidic; the reaction between water and atmospheric carbon dioxide lowers the pH of precipitation from neutral 7.0 to 5.6.
Describe the effects of acid deposition on soil and human-built structures.
Human-built structures: Acid deposition can harm structures such as statues, monuments, and buildings. Buildings from ancient Greece have been seriously eroded over the last half century by acid deposition. The damage happens because acid deposition reacts with building materials. When the hydrogen ion in acid deposition interacts with Limestone or marble, the calcium carbonate reacts with H+ and gives off Ca+2. In the process, the calcium carbonate material is partially dissolved. Soil: Metal bound in organic or inorganic compounds in soils and sediments are released into surface water. Because metal such as aluminum and Mercury can impair the physiological functioning of aquatic organisms, exposure can lead to species loss.
Montreal Protocol
In 1987 24 Nations signed the Montreal protocol. This was a commitment to reduce CFC production by 50% by the year 2000. The Amendments required the elimination of CFC production and use in the developed World by 1996.
Describe the mechanism by which endocrine disruptors impair normal endocrine system function.
In normal endocrine processes, hormones bind with receptors on cells to regulate the functioning of the body including growth, metabolism, and the development of reproductive organs. hormone disrupting chemicals mimic the hormones in the body and also bind to receptive cells and cause the cell to respond in ways that are not beneficial to the organism.
Explain the importance of stratospheric ozone to life on Earth
In the stratosphere ozone forms a necessary protective shield against radiation from the Sun, it absorbs ultraviolet light, a specific type, and prevents harmful ultraviolet radiation from reaching Earth. The ultraviolet wavelengths are classified into three groups; UVA, or low energy ultraviolet radiation, and the shorter higher energy UVB and UVC wavelengths, UV radiation of all types can damage the tissue and DNA of living organisms. - exposure to UVB radiation increases the risk of skin cancer and contracts and suppresses the immune system in humans. - - Exposure to UVB is also harmful to the cells of plants, and it reduces their ability to convert sunlight into usable energy. The layer of ozone in the stratosphere absorbs ultraviolet radiation, filtering out harmful UV rays from the Sun.
Human diseases
Infectious Diseases - diseases caused by pathogens (e.g., malaria) Acute Disease - short duration, progresses rapidly and requires urgent care (e.g., myocardial infarction, Ebola) Chronic Disease - longer duration, progresses more slowly, symptoms lasting > 3 months (e.g., cancer, autoimmune) top three leading causes of death in the world 1. Cardiovascular diseases 2. Cancers 3. Infectious diseases top three infectious diseases worldwide 1. Respiratory infections 2. Direherial diseases 3. Tuberculosis
Explain how to read and interpret an LD50 graph (percent mortality, LD50, threshold level).
LD50: The lethal dose of a chemical that kills 50% (threshold level) of the individuals in a dose response study. To compare the harmful effects of different chemicals scientists measure the LD50. The LD50 value helps assess the relative toxicity of a chemical to a particular species. Determination: To determine the LD50 endpoint from the graph, read from where the 50 percent point intercepts the dose. Response curve to the concentration along the x-axis. This concentration is the LD50 value. Threshold: dose at which an effect is first observed ED50 the effective dose that causes 50% of the individuals to display a harmful, but nonlethal, effect. As the LD50 decreases chemical toxicity increases (inversely related)
Clean Air Act
LIMITATIONS: Outdoor air quality only The original Act in 1970 identified six pollutants that significantly threatened the enviroment: carbon monoxide, particular matter, tropospheric ozone, and lead. These were called criteria air pollutants because under the Clean Air Act, EPA must specify allowable concentrations of each pollutant. In 2007, the Supreme Court ruled that carbon dioxide should be considered an air pollutant under the Clean Air Act, and in 2012, a federal appeals court agreed that the EPA is required to impose limits on harmful greenhouse gas emissions. Through the national ambient air quality standards (NAAQS), the EPA periodically specifies concentration limits for each air pollutant. One of the most innovative aspects of the Clean Air Act amendments was the provision for the buying and selling of allowances that authorize the owner to release a certain quantity of sulfur. Each allowance authorizes a power plant or Industrial Source to emit one ton of SO2 in a given year. sulfur allowances are awarded annually to existing sulfur emitters proportional to the amounts of sulfur they were emitting before 1990 and the emitters are not allowed to emit more sulfur then the amount for which they have permits.
Identify and briefly describe the five major types of harmful chemicals: neurotoxins, carcinogens, allergens, teratogens and endocrine disruptors
Neurotoxins: A chemical that disrupts the nervous systems of animals. Many insecticides are neurotoxins that interfere with an insect's ability to control its nerve transmissions. These animals can become completely paralyzed, cannot obtain oxygen, and quickly die. Other important neurotoxins include lead and Mercury. Carcinogens: A chemical that causes cancer. carcinogens cause cell damage and lead to uncontrolled growth of these cells either by interfering with the normal metabolic processes of the cell or by damaging the genetic material of the cell (mutagens). Some of the most well-known carcinogens include asbestos, radon, formaldehyde, and the chemicals found in tobacco. Allergens: A chemical that causes allergic reactions. allergens are capable of causing an abnormally strong response from the immune system which can cause breathing difficulties and even death. Teratogens: A chemical that interferes with the normal development of embryos or fetuses. One of the most infamous was the drug thalidomide prescribed to pregnant women during the late 1950s. Thousands of women gave birth to children with defects before the drug was taken off the market. One of the most common modern teratogens is alcohol. Endocrine disruptors: A chemical that interferes with the normal functioning of hormones in an animal's body. An endocrine disruptor can bind to receptor cells and cause the cell to respond in ways that are not beneficial to the organism. They impair normal growth and development of reproductive organs.
Electrostatic precipitators
Remove PM by using an electrical charge to make particles coalesce so they can be removed. Polluted air enters the precipitator and the electrically charged particles within are attracted to negative or positive charges on the sides of the precipitator. The particles collect and relatively clean gas exits the precipitator.
Compare and contrast industrial smog and photochemical smog in terms of their chemistry of formation, pollutants of concern, health effects and strategies to reduce their concentrations.
Only difference is chemistry and composition!!! Industrial smog: Smog dominated by sulfur dioxide and sulfate compounds. (London-type/gray/sulfurous) Formation: 1. Sulfur in oil and coal forms SOx - S + O2 → SO2 - 2SO2 + O2 → 2SO3 2. Sulfuric acid forms in the atmosphere SO3 + H2O → H2SO4 3. Sulfuric acid combines with ammonia in atmosphere to form the brown, solid ammonium sulfate - H2SO4 + 2NH3 → (NH4)2SO4 Typically exists in urban areas where factories burn fossil fuels such as coal, which creates smoke and sulfur dioxide that mix with fog droplets to create a thick blanket of haze close to the ground (burning coal, accumulates in winter) (SOx and particulates) Pollutants: Sulfur dioxide, sulfate compounds. Health Effects: When inhaled, smog irritates our airways, increasing our risk of serious heart and lung diseases. Reductions: Reduce the number of trips you take in your car. Reduce or eliminate fireplace and wood stove use. Avoid burning leaves, trash. Avoid using gas-powered lawn and garden equipment. Photochemical smog: A class of air pollutants formed as a result of sunlight acting on compounds such as nitrogen oxides. (Brown/LA-type) Formation: 1. 6-9 A.M. - people drive to work - N2 + O2 → 2NO 2. 9-11 A.M. - traffic decreases - 2NO + O2 → 2NO2 3. 11 A.M. - 4 P.M. - sunlight intensifies - NO2 + UV → NO + O - O2 + O → O3 *Ozone naturally breaks down in reactions with NO In the absence of VOCs, ozone will form during the daylight hours. After sunset, the ozone will break down. The VOCs will combine with nitrogen oxides to form photochemical oxidants which reduce the amount of ozone that will break down later and contribute to prolonged periods of photochemical smog. (Combustion engines, worst in summer) (VOCs, NOx, O3, CO) - caused by a mixture of oxidants and particulate mater. - is responsible for haze due to the scattering of light. Pollutants: VOCs, nitrogen oxides, ozone Health Effects: eye irritation, heart and lung problems which lead to emphysema, bronchitis, asthma. Reductions: Walk or bike to places that are short distances away instead of driving. Reduce electricity usage.
Describe the difference between primary and secondary pollutants. Provide two examples of primary and secondary pollutants.
Primary pollutants: A polluting Compound that comes directly out of a smoke stack, exhaust pipe, or natural emission source. - EX: CO2, SO2 Secondary pollutant: A primary pollutant that has undergone transformation in the presence of sunlight, water, oxygen, or other compounds. - EX: Ozone, formed as a result of the emissions of primary pollutants. Sulfate. (Occurs more rapidly during the day and in more wet environments) Primary Pollutants combine with sunlight, water, oxygen or other compounds to form Secondary Pollutants.
Explain how the solubility of a chemical influences its potential for bioaccumulation or biomagnification (e.g., DDT, Mercury, PCBs).
Solubility is how well a chemical dissolves in a liquid; the movement of a chemical in the environment depends in part on its solubility. Bioaccumulation: Chemicals that are soluble in fats and oils can also become stored in the fatty tissues of animals. DDT accumulates in the fatty tissues of aquatic Birds such as pelicans and those such as Eagles that feed on aquatic animals representing the process of bioaccumulation. Biomagnification: DDT is not soluble in water so when sprayed over water it quickly binds to particulates in the water and underlying soil or as quickly taken up by the Tiny Zoo Plankton that act as primary consumers on algae. Very low concentrations of DDT in the water bioaccumulates in the bodies of zooPlankton where it becomes approximately a thousand times more concentrated. Small fish eat the zoo plankton for many weeks and the DDT is further concentrated. - As methylmercury passes through successive trophic levels it becomes more concentrated (biomagnification) - Methylmercury stays in the environment for a very long time, making it very dangerous as it accumulates in the tissues of organisms. It is the only form of mercury able to cross the blood brain barrier where it can cause serious damage to the nervous system. - The PCBs are fat-soluble substances to which everyone is exposed through ingesting animal fats, inhalation, or dermal contact. Exposure to PCBs suppresses the immune system, thereby increasing the risk of acquiring several human diseases.
Describe the effects of acid deposition on terrestrial ecosystems (forests)
Terrestrial ecosystems: Acid deposition can alter soil chemistry, nutrient availability and plant growth. In their weakened condition, trees and shrubs become vulnerable to insects, diseases and fungus infestations. One of the most severely impacted areas of the world is the industrialized Ruhr Valley in West Germany. There, white fir trees became defoliated and died in the early 1970s. Diseases in spruce soon followed. The dominant tree in Vermont's Green Mountains, the red spruce, is suffering severe mortality and parts of the mountain range have become denuded. Sugar maples all over the northeastern U.S. and Canada are declining. In the Shenandoah and Great Smoky Mountains of the southeastern U.S., spruce and fir are failing to reproduce and are dying. Pine also is impacted.
Discuss possible solutions for counteracting the effects of acid deposition (e.g., how acidic compounds interact with limestone?)
The Clean Air Act Amendments of 1990 established an Acid Rain Program to reduce emissions of sulfur dioxide and nitrogen oxides at the lowest cost to society. To achieve reductions of 10 million tons of sulfur dioxide by the year 2010, the Act requires a two-phase tightening of the restrictions placed on fossil-fuel-fired power plants. To reduce sulfur dioxide emissions, fossil fuel burning plants can burn low-sulfur coal, install flue-gas desulfurization equipment (scrubbers) and implement clean combustion technologies.
Explain why the ozone "hole" first appeared over Antarctica (discuss the circumpolar vortex and stratospheric clouds) and why ozone concentrations are lowest in spring in the S. Hemisphere.
The ozone hole first appeared over Antarctica because atmospheric and chemical conditions unique to this region increase the effectiveness of ozone destruction by reactive halogen gasses. Ozone-depleting substances are present throughout the stratospheric ozone layer because they are transported great distances by atmospheric air motions. The severe depletion of the Antarctic ozone layer occurs because of the special atmospheric and chemical conditions that exist there and nowhere else on the globe. The very low winter temperatures in the Antarctic stratosphere cause polar stratospheric clouds (PSCs) to form. Special reactions that occur on PSCs, combined with the relative isolation of polar stratospheric air, allow chlorine and bromine reactions to produce the ozone hole in Antarctic springtime. - Stratospheric air in the polar regions is relatively isolated from other stratospheric regions for long periods in the winter months. The isolation comes about because of strong winds that encircle the poles, forming a polar vortex, which prevents substantial motion of air into or out of the polar stratosphere. Once chemical changes occur in polar regions from reactions on PSCs, the isolation preserves those changes for many weeks to months. - Reactions on the surfaces of liquid and solid PSCs can substantially increase the relative abundances of the most reactive chlorine gasses. These reactions convert the reservoir forms of reactive chlorine gasses, chlorine nitrate (ClONO2) and hydrogen chloride (HCl), to the most reactive form, ClO. With increased ClO, additional catalytic cycles involving ClO and BrO become active in the chemical destruction of ozone whenever sunlight is available.
Explain how thermal inversions form and dissipate and their relationship to air pollution events.
Thermal Inversion: A situation in which a relatively warm layer of air at mid-altitude covers a layer of cold, dense air below. 1) The warm layer of air trapped between the two cooler layers is an inversion layer. Because the air closest to the surface of Earth is denser than the air above it, the cool air and the pollutants within it do not rise. 2) Thus, the inversion layer traps emissions that then accumulate beneath it, and these trapped emissions can cause a severe pollution event. Thermal inversions that cause pollution events are common in some cities, where high concentrations of vehicle exhaust and industrial emissions are easily trapped by the inversion layer. Normal conditions = unstable air Inversion = warm air acts like a cap and shuts down convection, trapping smog over the city (stable air)
Catalytic converters
a device incorporated in the exhaust system of a motor vehicle, containing a catalyst for converting pollutant gases into less harmful ones. Honeycomb shape to maximize surface area All vehicles in the US are required to have one; it reduces nitrogen oxide, carbon monoxide, and hydrocarbon emissions. In order to work right the metals in the catalytic converters cannot be exposed to lead therefore gasoline could no longer contain lead. Decreases lead and nitrogen oxide pollutants.
