Presentation on theme: "The atmosphere is the key symbol of global interdependence. If we can’t solve some of our problems in the face of threats to this global commons, Then."— Presentation transcript:
The atmosphere is the key symbol of global interdependence. If we can’t solve some of our problems in the face of threats to this global commons, Then I can’t be very optimistic about the future of the world. Margaret Mead
The Atmosphere (18) We live at the bottom of a thin envelope of gases surrounding the Earth, called the atmosphere. It is divided into several layers based on drastic changes in temperature caused by differences in the absorption of incoming solar energy. Two other factors that vary throughout the atmosphere are density and atmospheric pressure. Both properties are influenced by gravity, which pulls gas molecules in the atmosphere towards the Earth’s surface. Atmospheric pressure is the force, or mass, per unit area of a column of air. (the weight of the air on your body). At sea level it is equal to 14.69 pounds per square inch. A barometer is used to measure atmospheric pressure. Density is the mass per volume of a substance. The density of air varies with elevation. The air at sea level is far more dense than the air in the high mountains. Atmospheric pressure decreases with altitude because there are fewer gas molecules at higher altitudes.
Altitude Sickness The available amount of oxygen to sustain mental and physical alertness decreases with altitude. Available oxygen drops as the air density drops. Dehydration due to the higher rate of water vapor lost from the lungs at higher altitudes may contribute to the symptoms of altitude sickness. The rate of ascent, altitude attained, amount of physical activity at high altitude, as well as individual susceptibility, are contributing factors to the onset and severity of high- altitude illness.Dehydration Altitude sickness—also known as acute mountain sickness (AMS): is a pathological effect of high altitude on humans, caused by acute exposure to low partial pressure of oxygen at high altitude. It commonly occurs above 2,400 meters (8,000 feet). It presents as a collection of nonspecific symptoms, acquired at high altitude or in low air pressure, resembling a case of "flu, carbon monoxide poisoning, or a hangover".effect of high altitude on humanspartial pressure of oxygenhigh altitudenonspecific symptoms People have different susceptibilities to altitude sickness; for some otherwise healthy people, acute altitude sickness can begin to appear at around 2000 meters (6,500 ft.) above sea level, such as at many mountain ski resorts. This is the most frequent type of altitude sickness encountered. Symptoms often manifest themselves six to ten hours after ascent and generally subside in one to two days as acclimatization occurs, but they occasionally develop into the more serious conditions (can be fatal). Symptoms include headache, fatigue, stomach illness, dizziness, and sleep disturbance. Exertion aggravates the symptoms.
Structure and Composition of the Atmosphere The atmosphere consists of several layers with different temperatures, pressures, and compositions. Atmospheric pressure (millibars) 120 Temperature 75 0 200 400600800 1,000 110 Thermosphere 65 100 90 Mesopause 55 80 70 Mesosphere 45 60 Stratopause 35 50 Altitude (miles) Altitude (kilometers) 40 25 Stratosphere 30 Tropopause 20 Ozone layer 15 10 Pressure Troposphere 5 (Sea level) 0 –80 –40 0 40 80 120 Temperature (˚C) 75-80% of the Earth’s air mass (most of the molecules are here) is found in the troposphere (the layer closest to the Earth). The layer is 11 miles thick at the equator and 5 miles over the poles. Location of Earth’s weather. About 99% of the air we breath consist of two gases: 1.Nitrogen 78% 2.Oxygen 21% 3..01-4% (humid regions) water vapor. 4..038% Carbon dioxide. 5.Trace amounts of argon, methane, ozone (O 3 ) and nitrous oxide. Temperature decreases with altitude until the tropopause, where there is a sudden rise in temperature in the next layer.
The Stratosphere and Ozone Layer The stratosphere is the second-lowest layer of Earth's atmosphere. It lies above the troposphere and is separated from it by the tropopause. This layer extends from the top of the troposphere at roughly 11 miles above Earth's surface to the stratopause at an altitude of about 30 miles. The stratosphere has less matter than the troposphere but the composition is almost the same.tropopausestratopause The atmospheric pressure at the top of the stratosphere is roughly 1/1000 the pressure at sea level. It contains the ozone layer, which is the part of Earth's atmosphere that contains relatively high concentrations of that gas. The stratosphere defines a layer in which temperatures rise with increasing altitude. This rise in temperature is caused by the absorption of ultraviolet radiation (UV) radiation from the Sun by the ozone layer.sea levelultraviolet radiationozone layer The stratospheric temperature profile creates very stable atmospheric conditions, so the stratosphere lacks the weather-producing air turbulence that is so prevalent in the troposphere. Consequently, the stratosphere is almost completely free of clouds and other forms of weather.
Ozone The stratosphere contains 1000x the ozone of the rest of the atmosphere; ozone forms in an equilibrium reaction when oxygen is converted to O 3 by lightning and/or sunlight UV. 3O 2 + UV 2O 3 This photoprotective layer or “global sunscreen” of ozone keeps 95% of the sun’s harmful UV radiation from reaching the Earth’s surface. The UV filter of the ozone allows us and other forms of life to exist on land and helps to protect us from sunburn, skin and eye cancer, cataracts and damage to the immune system. The ozone layer also keeps oxygen from being converted into photochemical ozone that is harmful when found near the ground.
The Mesosphere The mesosphere is the third highest layer of Earth's atmosphere, occupying the region above the stratosphere and below the thermosphere. It extends from the stratopause at an altitude of about 30miles to the mesopause at 50 miles above sea level. Temperatures drop with increasing altitude to the mesopause that marks the top of this middle layer of the atmosphere. It is the coldest place on Earth and has an average temperature around −85 °C.mesopause°C The mesosphere is also the layer where most meteors burn up upon atmospheric entrance. These burning meteors give off a fiery tail that we see from Earth and call shooting stars. It is too high above Earth to be accessible to jet- powered aircraft, and too low to support satellites and orbital or sub-orbital spacecraft. meteors
Thermosphere The thermosphere extends from the mesopause (at an altitude 50 mi) up to the thermopause at an altitude range 310–620 mi. The temperature of this layer can rise as high as 1,500 °C (2,700 °F), though the gas molecules are so far apart that its temperature in the usual sense is not very meaningful. The air is so rarefied (thin) that an individual molecule travels an average of 1 kilometer between collisions with other molecules. The thermosphere would still feel extremely cold to a human, the few molecules are incapable of transferring an adequate amount of energy to the skin of a human. In other words, a person would not feel warm because of the thermosphere's extremely low pressure.temperature in the usual sense This layer is completely cloudless and free of water vapor. However phenomena such as the aurora borealis and aurora australis are occasionally seen in the thermosphere. The International Space Station orbits in this layer, between 320 and 380 km (200 and 240 mi). aurora borealisaurora australis International Space Station
Exosphere The exosphere is a thin, atmosphere-like volume surrounding a planetary body where molecules are gravitationally bound to that body, but where the density is too low for them to behave as a gas by colliding with each other. In the case of bodies with substantial atmospheres, such as the Earth's atmosphere, the exosphere is the uppermost layer, where the atmosphere thins out and merges with interplanetary space. It is located directly above the thermosphere.moleculescolliding Earth's atmosphere thermosphere The main gases within the Earth's exosphere are the lightest atmospheric gases, mainly hydrogen, with some helium, carbon dioxide, and atomic oxygen near the base of the exosphere. Since there is no clear boundary between outer space and the exosphere, the exosphere is sometimes considered a part of outer space.hydrogenhelium carbon dioxideatomic oxygenouter space Atmospheric pressure decreasesAtmospheric pressure decreases
Sources of Outdoor Air Pollution Air pollution: the presence of chemicals in the atmosphere in concentrations high enough to harm organisms, ecosystems or human made materials. The effects can range from annoying to lethal. Natural sources of air pollution: 1.Dust blown by wind: Usually large areas of land with few or no vegetation 2.Methane, emitted by the digestion of food by animals, for example cattle.Methaneemitteddigestionanimalscattle 3.Radon gas from radioactive decay within the Earth's crust. Radon gas from natural sources can accumulate in buildings, especially in confined areas such as the basement and it is the second most frequent cause of lung cancer, after cigarette smoking.Radonradioactive decayEarth's crustcigarette 4.Pollutants from wildfires and volcanoes. Smoke and carbon monoxide from wildfires. Volcanic activity, which produces sulfur, chlorine, and ash particulates.Smokecarbon monoxidewildfires Volcanicsulfurchlorine 5.Volatile organics released by plants: Vegetation, in some regions, emits environmentally significant amounts of VOCs on warmer days to produce a seasonal haze of secondary pollutants. Most scents or odors are of VOCs. VOCs play an important role in communication between plants, and messages from plants to animals.scents or odors
Stationary and Mobile Sources Anthropogenic (man-made) sources: These are mostly related to the burning of multiple types of fuel. Stationary Sources include smoke stacks of power plants, manufacturing facilities (factories) and waste incinerators, as well as furnaces and other types of fuel-burning heating devices. In developing and poor countries, traditional biomass burning is the major source of air pollutants; traditional biomass includes wood, crop waste and dung.power plants Mobile Sources include motor vehicles, marine vessels, and aircraft.motor vehicles Fumes from paint, hair spray, varnish, aerosol sprays and other solventspainthair sprayvarnishaerosol sprays Waste deposition in landfills, which generate methane. Methane is highly flammable and may form explosive mixtures with air. Methane may displace oxygen in an enclosed space. Asphyxia or suffocation may result if the oxygen concentration is reduced to below 19.5% by displacement.landfills methane Military resources, such as nuclear weapons, toxic gases, germ warfare and rocketrynuclear weaponstoxic gasesgerm warfare rocketry
Primary and Secondary Pollution Primary pollution are harmful chemicals that are directly released into the air. While in the atmosphere some primary pollutants react with one another and the air to form secondary pollutants. Primary Pollutants COCO 2 Secondary Pollutants SO 2 NONO 2 Most hydrocarbons SO 3 Most suspended particles HNO 3 H 2 SO 4 H2O2H2O2 O3O3 PANs SourcesNaturalStationary Mobile Most NO 3 − and SO 4 2− salts
Types of Outdoor Air Pollutants 1. Carbon Oxides (Primary): Major primary pollutants produced by human activity include: Carbon monoxide (CO)- CO is a colorless, odorless, toxic yet non-irritating gas. It is a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide.incomplete combustion Carbon dioxide (CO 2 )-CO 2 is a colorless, odorless gas. 93% of carbon dioxide (CO 2 ) in the troposphere occurs as a result of the carbon cycle. 7% of CO 2 in the troposphere occurs as a result of human activities (mostly burning fossil fuels). Increasing levels have contributed to global warming and climate change. Human health problems: CO stops RBC’s from transporting oxygen efficiently. Chronic exposure can cause heart attacks, lung disease (asthma and emphysema). Can cause headaches, nausea, drowsiness, mental impairment, coma and death. CO detectors are now being required in new homes, before selling a home and for insurance. Annual fluctuations in CO 2 concentrations is due to seasonal photosynthetic activity of primary producers like plants.
2. Nitrogen oxides (primary) and nitric acid (secondary): Nitrogen oxide (NO) forms when nitrogen and oxygen gas in air react at the high-combustion temperatures in automobile engines and coal-burning plants. NO can also form from lightening and certain soil bacteria (nitrogen fixation part of the nitrogen cycle). NO reacts with air to form NO 2. Nitrogen dioxide (NO 2 ) reacts with water vapor in the air to form nitric acid (HNO 3 ) and nitrate salts (NO 3 - ) which are components of acid deposition (rain). Both NO and NO 2 contribute to photochemical smog. Nitrous dioxide N 2 O is a greenhouse gas emitted from fertilizers and animal wastes. Human health and other problems : Irritate eyes, nose and throat. Aggravate lungs (asthma and bronchitis) and increase respiratory infections. They can suppress plant growth and reduce visibility. They can be seen as a brown haze dome above or a plume downwind of cities.hazeplume Historical statues also suffer from acid deposition, the Acropolis in Athens has shown great destruction.
3. Sulfur dioxide (SO 2 primary) and sulfuric acid (secondary): Sulfur dioxide (SO 2 ): Colorless gas with a irritating odor. About one-third of SO 2 in the troposphere occurs naturally through the sulfur cycle (volcanoes). Two-thirds come from human sources (Anthropogenic ), mostly combustion (S+ O 2 SO 2 ) of sulfur-containing coal (electricity) and from oil refining and smelting of sulfide ores. Sulfur dioxide emissions are feeding the Asian Brown Cloud. SO 2 in the atmosphere can be converted to sulfuric acid (H 2 SO 4 ) and sulfate salts (SO 4 2- ) that return to earth as a component of acid deposition (rain). Human health and other problems: Reduce visibility, aggravate breathing problems, damage crops, trees, soils, and aquatic life in lakes. They corrode metals and damage paint, paper, leather and stone buildings and statues.
4. Suspended particulate matter (SPM Primary): SPM: Consists of a variety of solid particles and liquid droplets small and light enough to remain suspended in the air. Some particulates occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power plants, various industrial processes, unpaved roads and smoking also generate significant amounts of SPM. Anthropogenic sources account for 10 % of the atmosphere. Human health and other problems: The most harmful forms of SPM are fine particles (PM-10, with an average diameter < 10 micrometers) and ultrafine particles (PM-2.5). SPM Irritates eyes, nose and throat. Aggravate lungs and reduce life expectancy. Particulates reduce visibility, corrode metal, discolor clothes and plants. According to the EPA, SPM is responsible for about 60,000 premature deaths a year in the U.S. Statue Corroded by Acid Deposition and Other Forms of Air Pollution, RI, U.S.
5. Ozone (O 3 Secondary): Ozone: a colorless, highly reactive gas and is the major cause of photochemical smog. Human health and other problems: Cause and aggravate respiratory illness and heart disease, reduce resistance to the common cold and pneumonia, irritate the eyes, nose and throat. Damage plants, rubber in tires, fabrics, and paints. 6. Volatile organic compounds (VOCs Primary): Are organic compounds that exist as gases in the atmosphere. Most are hydrocarbons emitted by the leaves of many plants and methane. Methane (CH 4 ) is an extremely efficient greenhouse gas which contributes to enhanced global warming. 1/3 of the methane comes from natural sources, plants, wetlands and termites. global warming About two thirds of global methane emissions comes from anthropogenic sources, primarily rice paddies, landfills, oil and natural gas wells and cows (mainly belching). Human health and other problems: Long-term exposure to benzene can cause cancer, blood disorders, and immune system damage. 7. Chlorofluorocarbons (CFCs Primary) - harmful to the ozone layer. These are gases which are released from air conditioners, refrigerators, aerosol sprays, etc. CFC's on being released into the air rises to stratosphere. Here they come in contact with other gases and damage the ozone layer. This allows harmful ultraviolet rays to reach the earth's surface. Compounds like CFC, CCl 2 F 2 are also greenhouse gases and are completely anthropogenic (human made).stratosphereozone layer Human health and other problems: This can lead to skin cancer, disease to eye and can even cause damage to plants.
Lead in the Environment Because it is a chemical element, lead (Pb) does not break down in the environment. Lead is a potent neurotoxin that can harm the nervous system, is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive systems especially in young children. Statistics: 1.12,000-16,000 American children are treated yearly for lead poising and 200 die. 2.30% of survivors suffer from palsy (refers to various types of paralysis often accompanied by loss of feeling and uncontrolled body movements such as shaking) partial paralysis, blindness, and mental retardation. 3.Any amount of lead in the blood to fetuses and children under 6 can lower IQ by 7.4 points, shorten attention span, hyperactivity, and hearing damage. No level of lead in the blood is safe. The brains of adults who were exposed to lead as children. Areas of volume loss are shown in color.
Sources of Lead Past sources of lead in the U.S. 1.Leaded gasoline: Banned in the U.S. in 1976 2.Lead based paint: Banned in the U.S. in 1970 Reduced lead poisoning in children from 85% to 2.2%. Why are children still getting sick? 1.Peeling lead based paint from before the ban and lead contaminated dust in deteriorating or destroyed buildings. 2.In 2007, toy recall as China used lead paint on children’s toys. 3.2/3 of red lipstick in the U.S. contain high amounts of lead. None of them list lead as an ingredient. 4.Leach from water pipes and faucets when old pipes are still lead. An X ray demonstrating the characteristic finding of lead poisoning in humans—dense metaphyseal lines Metaphyseal growth arrest lines are seen in children who experience significant physical stress such as infection, lead poisoning or malnutrition over a sufficient period of time.
The top 20 lead-containing lipsticks from the FDA's 2012 review of 400 lipstick shades
Industrial SMOG Industrial smog is a mixture of sulfur dioxide, droplets of sulfuric acid, and a variety of suspended solid particles emitted mostly by burning coal and oil. Chemistry of industrial smog: Primary Secondary Some unburned coal ends up as soot in the atmosphere giving the smog a grey color.
Industrial SMOG’s Impact In most developed countries where coal and heavy oil is burned, industrial smog is not a problem due to reasonably good pollution control or with tall smokestacks that transfer the pollutant to rural areas. China relies heavily on coal and has some of the highest levels of industrial smog and 16 of the 20 most polluted cities. In China industrial smog prematurely kills 350,000 people a year (981 per day). Another 250,000 a year die form indoor pollution by burring coal for heating and cooking.
Photochemical SMOG Sunlight plus Cars Equals Photochemical Smog. A photochemical reaction is any chemical reaction activated by light. Photochemical smog is a mixture of air pollutants formed by the reaction of nitrogen oxides and volatile organic hydrocarbons under the influence of sunlight. Photochemical smog begins as the exhausts from morning commuters release NOx and VOCs (and CO 2 but not part of photochemical smog) into the air. The nitrogen containing pollutants give the air a reddish-brown colored smog. Ozone in the troposphere is a greenhouse gas and is formed directly from these photochemical reactions.
Photochemical smog is a mixture of ozone, nitric acid, aldehydes, and peroxyacyl nitrates (PANs). NO 2, O 3 and PANs are photochemical oxidants because these chemicals can react with compounds in your lungs. Contributing factors: Sunny, warm, dry cities with a lot of motor vehicles. Top polluted cities: 1.Los Angeles 2.Salt lake city 3.Denver 4.Sydney 5.Bangkok 6.Jakarta 7.Mexico city
Decreasing Outdoor Air Pollution 5 natural factors help reduce outdoor air pollution. 1.Particles heavier than air settle out naturally as a result of gravitational pull. 2.Rain and snow help cleanse the air as particles fall to the Earth with the precipitation. 3.Salty sea spray from the oceans wash out much of the particulates from the air over the oceans. 4.Winds sweep particles away, dilute them with cleaner air, and bring in fresh air. 5.Some pollutants are removed thorough chemical reactions: (SO 2 + O 2 = SO 3 + H 2 0 = H 2 SO 4 Acid deposition).
Factors that Increase Air Pollution Six factors that increase outdoor air pollution 1.Urban buildings can slow wind speed and reduce dilution of particles. 2.Hills and mountains can reduce air flow of air in valleys below and allow pollutant levels to build up at ground level. (San Fernando Valley). 3.High temperatures promote the chemical reactions that lead to photochemical smog. 4.Emissions of VOCs from plants like, oaks, poplars, and kudzu in urban areas lead to photochemical smog. 5.The grasshopper effect or Global distillation : Pollutants (especially persistent organic compounds POPs) from the lower latitudes hop to the poles where they are deposited. This occurs in the winter and explains why top predators in these areas have high levels of pollutants in their bodies even though most of these chemicals are not used there.
6. Temperature inversions are situations where warmer air traps cooler air and all of the pollution below. (remember warm air rises). Occur in two types of topography: A. Cold, cloudy weather in a valley surrounded by mountains can trap air pollutants. B. Areas with sunny climate, light winds, mountains on three sides and an ocean on the other. Warmer air Descending warm air mass Inversion layer Sea breeze Increasing altitude Decreasing temperature Temperature inversion stops atmospheric convection (which is normally present) from happening in the affected area and can lead to the air becoming stiller and murky from the collection of dust and pollutants that are no longer able to be lifted from the surface. This can become a problem in cities where many pollutants exist. Inversion effects occur frequently in big cities such as: Los Angeles, California, Mexico City, Mexico, Mumbai, India, Chengdu, China, Santiago, Chile, São Paulo, Brazil, Tehran, Iran, Vienna, Austria, Milan, Italy, Budapest, Hungary. Los AngelesCaliforniaMexico CityMexicoMumbaiIndiaChengduChina SantiagoChileSão PauloBrazilTehranIranViennaAustriaMilanItalyBudapestHungary
Acid Deposition Most coal burning power plants, ore smelters, and other industrial plants in developed countries use tall smokestacks to emit sulfur dioxides, nitrogen oxides, and particulates into the atmosphere to produce acidic chemicals that can travel long distances before returning to the earth’s surface. Tall smokestacks reduce local air pollution but can increase regional air pollution. Sulfur dioxide is the number one contributing factor to acid deposition. Wind Transformation to sulfuric acid (H 2 SO 4 ) and nitric acid (HNO 3 ) Windborne ammonia gas and some soil particles partially neutralize acids and form dry sulfate and nitrate salts Wet acid deposition (droplets of H 2 SO 4 and HNO 3 dissolved in rain and snow) Nitric oxide (NO) Sulfur dioxide (SO 2 ) and NO Dry acid deposition (sulfur dioxide gas and particles of sulfate and nitrate salts) Acid fog Lakes in shallow soil low in limestone become acidic Lakes in deep soil high in limestone are buffered Acid Rain pH less than5.6
Harmful Effects of Acid Deposition 1.Human respiratory disease. 2.Damages statues, monuments and buildings, metal and car finishes. 3.Leach toxic metals (lead and mercury) out of soil and rock and deposit them into water used for drinking. In lakes and ponds, biomagnification causes animals to accumulate these metals in their bodies making some fish inedible for humans especially pregnant women and young children. 4.Harms aquatic systems. Most fish cannot live in a pH less than 4.5. Aluminum leached into water can asphyxiate fish as mucus clogs their lungs. 5.Harm crops (soil pH drops below 5.1). Productivity (photosynthesis) decreases. 6.Harms forests by leaching essential plant nutrients like calcium, and magnesium and depositing mercury, lead, aluminum that weaken the trees and make them vulnerable to disease, insects and drought.
Most of the world’s forests are not being destroyed or seriously harmed by acid deposition, rather it is a regional problem harming forests and lakes that lie downwind from large car dominated cities and coal burning facilities without good pollution control.
Indoor Air Pollution The most threatening indoor air pollutants are smoke and soot from wood and coal cooking fires (a hazard found mostly in developing countries) and chemicals used in building materials and products. Indoor air pollution usually is a greater threat to human health than outdoor air pollution. If you are reading this lecture inside you are probably inhaling more air pollutant than you would outside. According to the WHO, indoor pollution is, for poor people, the world’s most serious pollution problem. According to the EPA, the four most dangerous indoor air pollutants in developed countries are: Tobacco smoke. Formaldehyde. Radioactive radon-222 gas. Very small fine and ultrafine particles.
Indoor Pollutants 1. Levels of 11 common pollutants are 2-5 times greater indoors. 2. Pollution inside your car when stuck in traffic can become 18 times greater than outside the car. 3. The health risks is magnified in developed contrives because people spend 70-98% of their time indoors. Household dust mites that feed on human skin and dust, live in materials such as bedding and furniture fabrics. Along with dust mites, cockroach droppings Can cause asthma attacks and allergic reactions in some people. Airborne spores of molds, fungal growths and mildew can aggravate asthma, allergies, cause headaches and grows in walls and under houses where it is damp. It is the single greatest cause of allergic reactions to indoor air. Radon-222, a radioactive gas found in some soils and rocks, can seep into some houses and increase the risk of lung cancer. Comes from natural radioactive decay that seeps into homes.
Sources and Paths of Entry for Indoor Radon-222 Gas The best way to protect your home from radon gas is to seal areas where radon enters or ventilate the area with window or vents. Most radon that enters homes comes from the decay of underlying bedrock.
Source: Chlorine-treated water in hot showers Possible threat: Cancer Source: Air fresheners, mothball crystals Threat: Cancer Source: Dry-cleaning fluid fumes on clothes Threat: Nerve disorders, damage to liver and kidneys, possible cancer Source: Aerosol sprays Threat: Dizziness, irregular breathing 1,1,1-Trichloroethane Source: Furniture stuffing, paneling, particleboard, foam insulation Threat: Irritation of eyes, throat, skin, and lungs; nausea; dizziness Formaldehyde Styrene Nitrogen oxides Source: Carpets, plastic products Threat: Kidney and liver damage Source: Unvented gas stoves and kerosene heaters, woodstoves Threat: Irritated lungs, children's colds, headaches Source: Tobacco smoke, woodstoves Threat: Lung cancer Benzo- α -pyrene Particulates Source: Pollen, pet dander, dust mites, cooking smoke particles Threat: Irritated lungs, asthma attacks, itchy eyes, runny nose, lung disease Source: Radioactive soil and rock surrounding foundation, water supply Threat: Lung cancer Radon-222 Tobacco smoke Source: Cigarettes Threat: Lung cancer, respiratory ailments, heart disease Asbestos Carbon monoxide Methylene chloride Source: Pipe insulation, vinyl ceiling and floor tiles Threat: Lung disease, lung cancer Source: Faulty furnaces, unvented gas stoves and kerosene heaters, woodstoves Threat: Headaches, drowsiness, irregular heartbeat, death Source: Paint strippers and thinners Threat: Nerve disorders, diabetes ChloroformPara-dichlorobenzeneTetrachloroethylene
Health Effects of Air Pollution Air pollution can contribute to asthma, chronic bronchitis, emphysema, lung cancer, heart attack, and stroke. The respiratory system’s defenses against air pollution: 1.Hairs in your nose filter out large particles. 2.Mucous lining in the upper respiratory tract captures small particles. 3.Sneezing and coughing help expel the trapped particles. 4.The respiratory tract is lined with tiny hairs called cilia that move particles and mucous to the throat to be swallowed or expelled. Prolonged exposure to fine and ultrafine air pollutants (including tobacco smoke) can overload our defenses. In the U.S. 17 million people suffer from asthma and 14 die from it each day.
Lung Diseases Chronic obstructive pulmonary disease (COPD), among others, is a type of obstructive lung disease characterized by chronically poor airflow. It typically worsens over time. The main symptoms include shortness of breath, cough, and sputum production. Tobacco smoking is the most common cause of COPD, with a number of other factors such as air pollution and genetics playing a smaller role.obstructive lung disease shortness of breathcoughsputum Tobacco smokingair pollutiongenetics Long-term exposure to irritants causes an inflammatory response in the lungs resulting in narrowing of the small airways and breakdown of lung tissue known as emphysema. The diagnosis is based on poor airflow as measured by lung function tests. In contrast to asthma, the airflow reduction does not improve significantly with the administration of medication. inflammatory responselung function testsasthma Lungs of a person who died of emphysema Normal lungs
Air Pollution is a Big Killer Each year, air pollution prematurely kills about 3 million people, mostly from indoor air pollution in developing countries. In the U.S., the EPA estimates that annual deaths related to indoor and outdoor air pollution range from 150,000 to 350,000. According to the EPA, each year more than 125,000 Americans get cancer from breathing diesel fumes. These are related to concentrations of coal burning plants.
Air Quality Laws and Regulations Legal, economic, and technological tools can help to clean up air pollution, but much greater emphasis should be focused on preventing air pollution. The Clean Air Act (1970, 1977, 1990) is a United States federal law designed to control air pollution on a national level. It requires the Environmental Protection Agency (EPA) to develop and enforce regulations to protect the public from airborne contaminants known to be hazardous to human health.United States federal lawair pollutionEnvironmental Protection Agencyregulationsairborne contaminants The National Ambient Air Quality Standards (NAAQS) are standards established by the United States Environmental Protection Agency under authority of the Clean Air Act that apply for outdoor air throughout the country. Primary standards are designed to protect human health especially sensitive populations such as children, the elderly, and individuals suffering from respiratory diseases.United StatesEnvironmental Protection AgencyClean Air Act Focus of the CAA and NAAQS Carbon monoxide Nitrogen oxides Sulfur dioxides Suspended particulate matter (less than PM-10) Ozone Lead Accomplishment of the CAA since 1970: Particulate Matter (PM)- down 78% Carbon Dioxide (CO 2 )- down 23% Nitrogen Dioxide (Nox)- up 14% Lead (Pb)- down 98% Sulfur Dioxide (SO 2 )- down 32% Air quality is worse in developing countries: Mexico City & Beijing: air exceeds WHO standards 350 days/year
To help reduce SO 2 emissions, the Clean Air Act authorized an emission trading (cap-and-trade) program. Clean Air Act Emission Trading Enables the 110 most polluting power plants to buy and sell SO 2 pollution rights. Each year these coal burning plants are given a set number of pollution credits. Each year extra pollution credits can be: 1.Given to other of the companies plants. 2.Keep for future plant expansions 3.Sell them to other companies, private citizens or environmental groups. Between 1990-2006, the emission trading system reduced emissions. However, the EPA reported the cap-and-trade system produced less emission reductions than were projected.
Reducing Outdoor Air Pollution There are a number of ways to prevent and control air pollution from coal-burning facilities. Electrostatic precipitator: are used to attract negatively charged particles in a smokestack into a collector. Used to keep particulates from being emitted into the air. Wet scrubber: fine mists of water vapor trap particulates and convert them to a sludge that is collected and disposed of usually in a landfill. Used to reduce SO 2 emissions.
There are a number of ways to prevent and control air pollution from motor vehicles. Because of the Clean Air Act, a new car today in the U.S. emits 75% less pollution than did pre-1970 cars. There is and increase in motor vehicle use in developing countries and many have no pollution control devices and burn leaded gasoline.
Little effort has been devoted to reducing indoor air pollution even though it poses a much greater threat to human health than outdoor air pollution. Environmental and health scientists call for us to focus on preventing air pollution (especially indoor) in developing countries.
I thought I saw a blue jay this morning. But the smog was so bad that it turned out to be a cardinal holding its breath. Michael J Cohen
Climate Change (19) The overwhelming scientific consensus is that the earth’s atmosphere is warming rapidly, mostly because of human activities, and that this will lead to significant climate change during this century. Global warming and cooling are not new. Changes in the Earth’s climate over the past 4.5 billion years is not unusual. The planets climate has been altered by: 1.Volcanic emissions 2.Changes in solar input 3.Continents slowly moving 4.Impacts of meteors When volcanoes erupt, they emit a mixture of gases and particles into the air. Some of them, such as ash and sulfur dioxide, have a cooling effect, because they (or the substances they cause) reflect sunlight away from the earth. Others, such as CO 2, cause warming by adding to the greenhouse effect. Although volcanoes emit carbon dioxide they have a greater cooling effect on the Earth.greenhouse effect The cooling influence is particularly marked in the case of large eruptions able to blast sun- blocking particles all the way up to the stratosphere – such as Mount Pinatubo in 1991, which caused a significant dip in global temperatures in the following year or two.Mount Pinatubo
Global Cooling and Warming Over the past 900,000 years, the troposphere has experienced prolonged periods of global cooling and global warming. These alternating cycles of freezing and thawing are known as glacial and interglacial (between ice ages) periods. For the past 10,000 years, we have been lucky enough to live in an interglacial period characterized by a fairly stable climate. This allowed agriculture and then cities to flourish. For the past 1,000 years, temperatures have remained fairly stable but began to rise during the last century. The last glacial period, popularly known as the Ice Age, was the most recent glacial period occurring during the last years of the Pleistocene, from approximately 110,000 to 12,000 years ago.glacial period Pleistocene
The Greenhouse Gases Name:Origin:Sources: Water vapor (H 2 O)Most abundant nonanthropogenic greenhouse gas. Clouds and water vapor Carbon Dioxide (CO 2 )Both non-anthropogenic and anthropogenic Cellular respiration Burning fossil fuels and deforestation Methane (CH 4 )Both non-anthropogenic and anthropogenic Swamp gas (by product of anaerobic respiration), stored underground, and livestock. Fracking, livestock, and landfills. Nitrous oxide (NOx)Both non-anthropogenic and anthropogenic Produced during denitrification (nitrogen cycle) Burring fossil fuels Ozone (O 3 )Both non-anthropogenic and anthropogenic Natural in stratosphere Man made in the troposphere Chlorofluorocarbons (CFC’s)Only anthropogenicFreon refrigerators and fire extinguishers. A greenhouse gas (sometimes abbreviated GHG) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect.gasabsorbs emitsthermal infrared greenhouse effect
Atmospheric lifetime and GWP relative to CO 2GWP Gas name Chemical formula Lifetime (years) Global warming potential (GWP) for given time horizon 20-yr100-yr500-yr Carbon dioxide CO 2 variable111 MethaneCH 4 1272257.6 Nitrous oxideN2ON2O114289298153 CFC’sCCl 2 F 2 10011 00010 9005 200 The Global warming potential (GWP) is the ability of the greenhouse gas to absorb and trap thermal radiation (Infrared (IR) or heat). Although CFC’s levels are lower than carbon dioxide, methane and nitrous oxide, their GWP is much higher.
The Natural Greenhouse Effect Along with solar energy, a natural process called the greenhouse effect warms the earth’s lower troposphere and surface because of the presence of greenhouse gases. Without the natural greenhouse effect the world would be a cold uninhabitable place. The major greenhouse gases in the lower atmosphere are water vapor, carbon dioxide, methane, and nitrous oxide. These gases have always been present in the earth’s troposphere in varying concentrations. Fluctuations in these gases, plus changes in solar output are the major factors causing the changes in tropospheric temperature over the past 400,000 years. Oceans store CO 2 and heat, evaporate and receive water, move stored heat to other parts of the world. Oceans represent the largest active carbon sink on Earth, absorbing more than a quarter of the carbon dioxide that humans put into the air. A carbon sink is a natural or artificial reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period.carbon
Human Activities Emit Large Amounts of Greenhouse Gas Since the beginning of the Industrial Revolution about 275 years ago, human actions have led to significant increase in greenhouse gases. 1.Carbon dioxide (CO 2 ) 2.Methane (CH 4 ) 3.Nitrous oxide (N 2 O) In 2005, an ice core showed that CO 2 levels in the troposphere are the highest they have been in 650,000 years. Carbon dioxide and methane levels in the lower atmosphere correlate fairly closely with global temperature changes. Increases in average concentrations of three greenhouse gases in the troposphere between 1860 and 2004, mostly due to fossil fuel burning (including coal for electricity), deforestation, and agriculture.
CO 2 Increases If Carbon dioxide emissions continue to increase at the current exponential rate of about 3.3% per year, levels in the atmosphere will rise to: 1.560 ppm by 2050 2.1390 ppm by 2100 Bringing about major ecological and economic disruption. Scientific studies indicate that we should try to prevent CO 2 levels from exceeding 450 ppm, the estimated threshold, or irreversible tipping point. As over 2007 the largest CO 2 producers in order: 1.United States 25% 2.China 5% 3.The European Union (27 countries) 4.Indonesia 5.Russia 6.Japan 7.India
CO 2 Decreases Some natural process remove carbon dioxide from the atmosphere: 1.Photosynthetic organisms: Carbon dioxide + Water + sunlight = Glucose + oxygen. 2.Diffusion into the oceans from the atmosphere. 3.Indirectly removed from the atmosphere by coral reefs as that use carbon dioxide to make calcium carbonate, which is the main component of corals. Unfortunately the anthropogenic increases far outweigh the natural decreases which contributes to global warming. Carbon sequestration is the process of capture and long-term storage of atmospheric carbon dioxide (CO 2 )capturecarbon dioxide
Intergovernmental Panel on Climate Change (IPCC)IPCC The 20 th century was the hottest century in the past 1000 years. The IPCC concludes that there is evidence that the earth’s troposphere is warming, mostly because of human actions: 1. 1906–2005: Ave. temp increased about 0.74˚C 2. 1970–2005: Annual greenhouse emissions up 70% 3. Over the past 50 years, Arctic temperatures have risen almost twice as fast as those in the rest of the world. 4. Melting of glaciers and floating sea ice, Prolonged droughts: increasing 5. Last 100 years: sea levels rose 10–20 cm. mostly due to runoff from melting and land-based ice and the expansion of ocean water as temperatures rise. 6. Warmer temperatures in Alaska, Russia, and the Arctic are melting permafrost releasing more CO 2 and CH 4 into the troposphere. The Big Melt: Arctic sea ice dropped 20%
The Scientific Consensus about Future Climate Change Measured and projected changes in the average temperature of the atmosphere. Scientists have identified several natural and human influenced factors that might amplify (positive feedback Harmful or speed it up) and some can dampen (negative feedback or slow it down) projected global warming. 1.Hotter sun? The sun’s output has varied throughout history. Since 1975 the troposphere has warmed but the stratosphere has cooled. This is not what a warmer sun would do. The atmosphere is heating from the bottom up. 2. Can the oceans save us? The oceans have absorbed 50% of the CO 2 released from the start of the Industrial Revolution. The solubility of CO 2 decreases as temperature increases. This could speed up global warming as CO 2 bubbles out of the oceans and into the atmosphere. The oceans have warmed by 1.2 F o in the last century. There is uncertainty about how much CO 2 and heat the oceans can remove from the troposphere and how long the heat and CO 2 might remain there.
3. More Clouds? Warmer temperatures create more clouds Thick, light-colored low altitude clouds: decrease surface temperature by reflecting more sunlight back to space. Thin, cirrus clouds at high altitudes: increase surface temperature by holding heat in. What are some possible effects of a warmer atmosphere? Why should we care? What is the big deal? The projected rapid change in the atmosphere's temperature during this century is very likely to increase drought and flooding, shift areas where food can be grown, raise sea levels, result in intense heat waves, and cause the premature extinction of many species. Tipping point and irreversible climate change. Worst-case scenarios Ecosystems collapsing Low-lying cities flooded Wildfires in forests Prolonged droughts: grasslands become dust bowls More destructive storms Glaciers shrinking; rivers drying up
Global Warming Global warming (Global climate change): refers to an unequivocal and continuing rise in the average temperature of Earth's climate system. Since 1971, 90% of the warming has occurred in the oceans. Despite the oceans' dominant role in energy storage, the term "global warming" is also used to refer to increases in average temperature of the air and sea at Earth's surface. Since the early 20th century, the global air and sea surface temperature has increased about 1.2 °F, with about two-thirds of the increase occurring since 1980. Each of the last three decades has been successively warmer at the Earth's surface than any preceding decade since 1850. This global climate change occurs because higher concentration of greenhouse gases in the troposphere absorb (trap) escaping inferred radiation (heat) and trap it near the Earth’s surfaceclimate system Global warming is changing ocean currents Global warming could alter ocean currents and cause both excessive warming and severe cooling. Global warming will increase deaths from: Heat and disruption of food supply. Spread of tropical diseases to temperate regions. Increase the number of environmental refugees.
The Browning of the Earth Drought occurs when evaporation greatly exceeds precipitation for a prolonged period. Global warming has increased the area of land experiencing severe drought from 15% to 30%. Effects of drought and the browning of the Earth: 1.Less moisture in soil and surface water will decline 2.Primary productivity will decline 3.Growth of trees and other plants will decline which will reduce carbon dioxide removal from the atmosphere intensifying global warming. (positive feedback) 4.Forest and grassland fires will increase adding carbon dioxide to the atmosphere. 5.Lakes will shrink and disappear. Some rivers will not reach the ocean. 6.1-3 billion people will face severe water shortages 7.Biodiversity will decrease especially specialist species, deserts and chaparrals will increase. 8.It will accelerate global warming and lead to even more drought. 9.The hardest hit ecosystems (when considering species loss) are fragile ecosystems like coral reefs, polar seas, costal wetlands, arctic tundra and mountain tops. 10.Shift the areas in which crops can be grown. In a warmer world, agricultural productivity may increase in some areas and decrease in others. 11.Global warming will lead to prolonged heat waves and droughts in some areas and prolonged heavy rains and increased flooding in other areas. 12.A warmer troposphere can decrease the ability of the ocean to remove and store CO 2 by decreasing the nutrient supply for phytoplankton and increasing the acidity of ocean water. 13.Insects carrying disease are on the move and heat related deaths among the elderly are on the rise.
Ice and Snow are Melting Light colored ice and snow helps to cool the Earth by reflecting incoming solar energy. 1.Melted ice will expose darker land that will absorb solar energy causing polar regions to warm faster than lower latitudes. 2.Sea ice will melt increasing atmospheric temperatures speeding up global warming. 3.Sea ice plays a vital role in where and how much precipitation falls per year. These changed weather patterns can affect food production by limiting irrigation water in many places. 4.Melting land ice is contributing to sea levels rising. 5.Melting permafrost is reducing the size of the arctic tundra and releasing stored methane accelerating global warming. Sea levels are rising 1.Sea level is expected to rise.6-1.9 feet this century from the thermal expansion of water as it warms (2/3) and melting of land based ice (1/3). 2.Destroy 1/3 of coastal estuaries, wetlands, and coral reefs. 3.Flood some coastlines and lowlands where much of the world’s rice is grown. 4.Contamination of freshwater coastal aquifers with saltwater decreasing supplies of groundwater used for irrigation. 5.Submerge low-lying islands which is the home for 5% of the world’s population.
Water Vapor Increased global temperature will cause more evaporation which will increase water vapor in the troposphere. This increased water vapor may lead to more cloud formation which can alleviate (negative feedback) or accelerate (positive feedback) global warming. The chemical composition of the troposphere is essentially uniform, with the notable exception of water vapor. The source of water vapor is at the surface through the processes of evaporation and transpiration.water vapor evaporationtranspiration
Dealing with global Warming Climate change is such a difficult problem to deal with because: 1. The problem is global. 2. The effects will last a long time. 3. The problem is a long-term political issue. 4. The harmful and beneficial impacts of climate change are not spread evenly. 5. Many actions that might reduce the threat are controversial because they can impact economies and lifestyles. Two ways to deal with global warming: Mitigation that reduces greenhouse gas emissions. Adaptation, where we recognize that some warming is unavoidable and devise strategies to reduce its harmful effects. To slow the rate of global warming and climate change, we can increase energy efficiency, sharply reduce greenhouse gas emissions, rely more on renewable energy resources, and slow population growth. Governments can subsidize energy efficiency and renewable energy use, tax greenhouse gas emissions, set up cap-and-trade emission reduction systems, and help to slow population growth.
WHAT IS BEING DONE TO REDUCE GREENHOUSE GAS EMISSIONS? The Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) is an international treaty that sets binding obligations on industrialized countries to reduce emissions of greenhouse gases. According to the UNFCC website, the Protocol "recognizes that developed countries are principally responsible for the current high levels of GHG emissions in the atmosphere as a result of more than 150 years of industrial activity.United Nations Framework Convention on Climate Changegreenhouse gases Getting countries to agree on reducing their greenhouse emissions is difficult. A 2006 poll showed that 83% of Americans want more leadership from federal government on dealing with global warming. International Climate Negotiations: It requires 38 participating developed countries to cut their emissions of CO 2, CH 4, and N 2 O to 5.2% below their 1990 levels by 2012. Developing countries were excluded. 1. The U.S. did not sign, but California and Maine are participating. 2. U.S. did not sign because developing countries such as China, India and Brazil were excluded. The Kyoto Protocol will have little effect on future global warming without support and action by the U.S., China, and India.
Ozone Depletion Widespread use of certain chemicals has reduced ozone levels in the stratosphere, which allows for more harmful ultraviolet radiation to reach the earth’s surface. The ozone layer keeps about 95% of the sun’s harmful UV radiation from reaching the earth’s surface. Chlorofluorocarbons (CFCs) and other halogenated ozone depleting substances (ODS) are mainly responsible for man-made chemical ozone depletion. CFCs were invented by Thomas Midgley, Jr. in the 1920s. They were used in air conditioning and cooling units, as aerosol spray propellants prior to the 1970s, and in the cleaning processes of delicate electronic equipment. They also occur as by-products of some chemical processes. No significant natural sources have ever been identified for these compounds—their presence in the atmosphere is due almost entirely to human manufacture.Thomas Midgley, Jr.air conditioning aerosol spray propellants In 1988 CFCs were no longer manufactured due in part to The Montreal Protocol on Substances that Deplete the Ozone Layer Ozone depletion describes two distinct but related phenomena observed since the late 1970s: a steady decline of about 4% per decade in the total volume of ozone in Earth's stratosphere (the ozone layer), and a much larger springtime decrease in stratospheric ozone over Earth's polar regions.ozoneEarthstratosphere ozone layer Each CFC molecule can last 65- 385 years In 1992 the Copenhagen Protocol called for other ODS to be phased out.
Sun Ultraviolet light hits a chlorofluorocarbon (CFC) molecule, such as CFCl 3, breaking off a chlorine atom and leaving CFCl 2. UV radiation ClO + O → Cl + O 2 Repeated many times Cl + O 3 → ClO + O 2 Summary of Reactions CFCl 3 + UV → Cl + CFCl 2 Cl F C F Once free, the chlorine atom is off to attack another ozone molecule and begin the cycle again. Cl O O O Ozone O O O O O O A free oxygen atom pulls the oxygen atom off the chlorine monoxide molecule to form O 2. O Cl O O O O The chlorine atom and the oxygen atom join to form a chlorine monoxide molecule (ClO). O O Cl The chlorine atom attacks an ozone (O 3 ) molecule, pulling an oxygen atom off it and leaving an oxygen molecule (O 2 ). C
During the Antarctic spring (our October) of each year up to half of the ozone in the stratosphere over Antarctica and a smaller amount over the Artic is depleted causing the ozone hole. Ozone thinning: caused by CFCs and other ozone depleting chemicals (ODCs). Increased UV radiation reaching the earth’s surface from ozone depletion in the stratosphere is harmful to human health, crops, forests, animals, and materials such as plastic and paints. To reverse ozone depletion, we must stop producing ozone-depleting chemicals and adhere to the international treaties that ban such chemicals.
Human Health Worse sunburn More eye cataracts More skin cancers (Australia, New Zealand, South America, South Africa impacted hardest as ozone depleted air over Antarctica move north) Immune system suppression Food and Forests Reduced yields for some crops, destroys plant cells reducing photosynthesis Reduced seafood supplies from reduced phytoplankton Decreased forest productivity for UV-sensitive tree species Wildlife Increased eye cataracts in some species Decreased population of aquatic species sensitive to UV radiation Reduced population of surface phytoplankton Disrupted aquatic food webs from reduced phytoplankton Air Pollution and Materials Increased acid deposition Increased photochemical smog Degradation of outdoor paints and plastics Global Warming Accelerated warming because of decreased ocean uptake of CO2 from atmosphere by phytoplankton and CFCs acting as greenhouse gases Effects of Ozone Depletion Natural Capital Degradation
Climate Change Atmosphere Global Warming E Gases Causes: 1.Cars, Coal power plants and rice farming (rice paddies are one of the largest human sources of methane). 2.Cattle belching and flatulent. 3.Landfills (Methane) Chemicals: H 2 0, CH 4, CO 2, NOx, and CFC’s E Gases Solar radiation (IR) trapped in troposphere Ozone depletion Stratosphere suppose to absorb 95-99% of UV Environmental effects: 1.Glaciers melting increase sea level. 2.Ocean acidification 3.Stronger storms 4.More droughts and floods 5.Thermal expansion of the oceans. Chemicals: CFC’s Causes: 1.Aerosols 2.Propellants 3.Refrigerators 4.Styrofoam burning Environmental effects: 1.Destroys plant cells can’t photosynthesize 2.Animal cataracts and skin problems. Treaty: Kyoto protocol Treaty: Montreal protocol