Presentation on theme: "Chapter 20: air pollution Pollution unit. 20.1 Layers of the Atmosphere."— Presentation transcript:
Chapter 20: air pollution Pollution unit
20.1 Layers of the Atmosphere
Atmospheric pressure (millibars) , (Sea Level) –80– Pressure = 1,000 millibars at ground level Temperature (˚C) Altitude (kilometers) Altitude (miles) Thermosphere Heating via ozone Mesosphere Stratosphere Ozone layer Heating from the earth Troposphere Temperature Pressure Highlights: Pressure decreases with altitude until it reaches zero Troposphere is the layer we live in; mostly N and O; weather; colder as you go up Stratosphere: has the ozone layer; warmer as you go up Environmental science focuses mostly on those two layers
What SPF is that ozone? Stratospheric ozone absorbs 95% of UV radiation 3O 2 + UV 2 O 3 Tropospheric ozone is harmful to plants, animals, and humans. Tropospheric ozone is made when air pollutants undergo chemical reactions because of UV exposure.
Which ozone is which? The oxygen atom generated from the initial reaction reacts with atmospheric, diatomic oxygen, to form ozone. This polluting ozone of the lithosphere, traps heat and contributes to thermal inversion.
20.2 Outdoor Air Pollution.
Primary & Secondary Pollutants PlayPlay intro video
Primary Pollutants Secondary Pollutants SourcesNatural Stationary COCO 2 SO 2 NONO 2 Most hydrocarbons Most suspended particles SO 3 HNO 3 H 2 SO 4 H2O2H2O2 O3O3 PANs MostandsaltsNO 3 – Mobile SO 4 2 – Primary vs. Secondary
Tip – Cant remember what organic compounds are??? View my PS (Chapter 9) PPT online for a quick refresher.
Table 20-1 Page 436 Major classes of air pollutants Class Carbon oxides Sulfur oxides Nitrogen oxides Volatile organic compounds (VOCs) Suspended particulate matter (SPM) Photochemical oxidants Radioactive substances Hazardous air pollutants (HAPs), which cause health effects such as cancer, birth defects, and nervous system problems Examples Carbon monoxide (CO) and carbon dioxide (CO 2 ) Sulfur dioxide (SO 2 ) and sulfur trioxide (SO 3 ) Nitric oxide (NO), nitrogen dioxide (NO 2 ), nitrous oxide (N 2 O) (NO and NO 2 often are lumped together and labeled NOx) Methane (CH 4 ), propane (C 3 H 8 ), chlorofluorocarbons (CFCs) Solid particles (dust, soot, asbestos, lead, nitrate, and sulfate salts), liquid droplets (sulfuric acid, PCBs, dioxins, and pesticides) Ozone (O 3 ), peroxyacyl nitrates (PANs), hydrogen peroxide (H 2 O 2 ), aldehydes Radon-222, iodine-131, strontium-90, plutonium-239 (Table 3-1, p. 49) Carbon tetrachloride (CCl 4 ), methyl chloride (CH 3 Cl), chloroform (CHCl 3 ), benzene (C 6 H 6 ), ethylene dibromide (C 2 H 2 Br 2 ), formaldehyde (CH 2 O 2 )
CARBON MONOXIDE (CO) Description: Colorless, odorless gas that is poisonous to air-breathing animals; forms during the incomplete combustion of carbon-containing fuels (2 C + O2 2 CO). Major human sources: Cigarette smoking (p. 409), incomplete burning of fossil fuels. About 77% (95% in cities)comes from motor vehicle exhaust. Health effects: Reacts with hemoglobin in red blood cells and reduces the ability of blood to bring oxygen to body cells and tissues. This impairs perception and thinking; slows reflexes; causes headaches, drowsiness, dizziness, and nausea; can trigger heart attacks and angina; damages the development of fetuses and young children; and aggravates chronic bronchitis, emphysema, and anemia. At high levels it causes collapse, coma, irreversible brain cell damage, and death. Carbon Monoxide Table 20-2 Major Outdoor Air Pollutants
Table 20-2 Page 438 Table 20-2 Major Outdoor Air Pollutants NITROGEN DIOXIDE (NO 2 ) Description: Reddish-brown irritating gas that gives photochemical smog its brownish color; in the atmosphere can be converted to nitric acid (HNO 3 ), a major component of acid deposition. Major human sources: Fossil fuel burning in motor vehicles (49%) and power and industrial plants (49%). Health effects: Lung irritation and damage; aggravates asthma and chronic bronchitis; increases susceptibility to respiratory infections such as the flu and common colds (especially in young children and older adults). Environmental effects: Reduces visibility; acid deposition of HNO 3 can damage trees, soils, and aquatic life in lakes. Property damage: HNO 3 can corrode metals and eat away stone on buildings, statues, and monuments; NO 2 can damage fabrics. Nitrogen Dioxide
Table 20-2 Page 438 Table 20-2 Major Outdoor Air Pollutants SULFUR DIOXIDE (SO 2 ) Description: Colorless, irritating; forms mostly from the combustion of sulfur containing fossil fuels such as coal and oil (S + O 2 SO 2 ); in the atmosphere can be converted to sulfuric acid (H 2 SO 4 ), a major component of acid deposition. Major human sources: Coal burning in power plants (88%) and industrial processes (10%). Health effects: Breathing problems for healthy people; restriction of airways in people with asthma; chronic exposure can cause a permanent condition similar to bronchitis. According to the WHO, at least 625 million people are exposed to unsafe levels of sulfur dioxide from fossil fuel burning. Environmental effects: Reduces visibility; acid deposition of H 2 SO 4 can damage trees, soils, and aquatic life in lakes. Property damage: SO 2 and H 2 SO 4 can corrode metals and eat away stone on buildings, statues, and monuments; SO 2 can damage paint, paper, and leather. Sulfur Dioxide
Table 20-2 Page 438 Table 20-2 Major Outdoor Air Pollutants SUSPENDED PARTICULATE MATTER (SPM) Description: Variety of particles and droplets (aerosols) small and light enough to remain suspended in atmosphere for short periods (large particles) to long periods (small particles; Figure 20-6, p. 441); cause smoke, dust, and haze. Major human sources: Burning coal in power and industrial plants (40%), burning diesel and other fuels in vehicles (17%), agriculture (plowing, burning off fields), unpaved roads, construction. Health effects: Nose and throat irritation, lung damage, and bronchitis; aggravates bronchitis and asthma; shortens life; toxic particulates (such as lead, cadmium, PCBs, and dioxins) can cause mutations, reproductive problems, cancer. Environmental effects: Reduces visibility; acid deposition of H 2 SO 4 droplets can damage trees, soils, and aquatic life in lakes. Property damage: Corrodes metal; soils and discolors buildings, clothes, fabrics, and paints. Suspended Particulate Matter
Table 20-2 Page 438 Table 20-2 Major Outdoor Air Pollutants LEAD Description: Solid toxic metal and its compounds, emitted into the atmosphere as particulate matter. Major human sources: Paint (old houses), smelters (metal refineries), lead manufacture, storage batteries, leaded gasoline (being phased out in developed countries). Health effects: Accumulates in the body; brain and other nervous system damage and mental retardation (especially in children); digestive and other health problems; some lead-containing chemicals cause cancer in test animals. Environmental effects: Can harm wildlife. Lead
Table 20-2 Page 438 Table 20-2 Major Outdoor Air Pollutants OZONE (O 3 ) Description: Highly reactive, irritating gas with an unpleasant odor that forms in the troposphere as a major component of photochemical smog (Figures 20-3 and 20-5). Major human sources: Chemical reaction with volatile organic compounds (VOCs, emitted mostly by cars and industries) and nitrogen oxides to form photochemical smog (Figure 20-5). Health effects: Breathing problems; coughing; eye, nose, and throat irritation; aggravates chronic diseases such as asthma, bronchitis, emphysema, and heart disease; reduces resistance to colds and pneumonia; may speed up lung tissue aging. Environmental effects: Ozone can damage plants and trees; smog can reduce visibility. Property damage: Damages rubber, fabrics, and paints. Ozone
20.3 Photochemical and Industrial Smog
Smog Photochemical: brown air smog Caused by UV reacting with chemicals (NOx, VOCs in the atmosphere) Found in modern cities, especially in warm, sunny areas. Industrial smog: gray air smog Caused by burning of fossil fuels, adds sulfur to air. Rare in developed countries now as soot is removed by filters..
Photochemical Smog Nitrogen oxide is an essential ingredient of photochemical smog that is produced during the high temperatures associated with combustion of vehicles engines. Be sure to look at sheet Chemistry is indeed relevant to APES.
Initial reaction of nitrogen dioxide with sunlight
Factors in smog formation Precipitation Salty sea spray Wind Reduce factory/car emissions Urban buildings Hills and mountains High temperatures Grasshopper Effect Decrease smogIncrease smog
Grasshopper Effect This is one reason why the dangerous chemicals Canada banned more than 20 years ago continue to turn up in the Great Lakes.
View Chemistry is indeed relevant to APES. See equation – reactants and products of photochemical smog on sheet. Hydrocarbons (including VOCs), carbon monoxide, and nitrogen oxides from vehicle exhausts are irradiated by sunlight in the presence of oxygen gas. The resulting reactions produce a potentially dangerous mixture that include other NOx, ozone, and irritating organic compounds (VOCs), as well as CO2 and H2O vapor
Thats just smoke out your…….
20.4 Regional Outdoor Air Pollution from Acid Deposition
Acid Rain PlayPlay intro video
Chemistry and Acid Rain The pH of rainwater is normally slightly acidic, at about 5.6, due mainly to reaction of carbon dioxide with water to form carbonic acid. Refer to Chemistry is indeed relevant to APES.
Gases from natural events Volcanic eruptions, forest fires, and lightning produce sulfur dioxide, sulfur trioxide, and nitrogen dioxide. These gases can react with atmospheric water in much the same way that carbon dioxide does to produce sulfurous acid, sulfuric acid, nitric acid and nitrous acid. Refer to Chemistry is indeed relevant to APES.
Wind Transformation to sulfuric acid (H 2 SO 4 ) and nitric acid (HNO 3 ) Nitric oxide (NO) Acid fog Ocean Sulfur dioxide (SO 2 ) and NO Windborne ammonia gas and particles of cultivated soil partially neutralize acids and form dry sulfate and nitrate salts Dry acid deposition (sulfur dioxide gas and particles of sulfate and nitrate salts) Farm Lakes in deep soil high in limestone are buffered Lakes in shallow soil low in limestone become acidic Wet acid deposition (droplets of H 2 SO 4 and HNO 3 dissolved in rain and snow) Acid Rain formation
Wind Ocean Farm Which location does sulfuric & nitric acids transform? Y Z X
Wind Ocean Farm Identify the type of acid deposition at point Y Y Z Transformation to sulfuric acid (H 2 SO 4 ) and nitric acid (HNO 3 )
Wind Ocean Farm Identify the type of acid deposition at point Z X Z Dry acid deposition
Wind Ocean Farm Great Job!! X Y Wet acid deposition
Primary Pollutants Secondary Pollutants SourcesNatural Stationary COCO 2 SO 2 NONO 2 Most hydrocarbons Most suspended particles SO 3 HNO 3 H 2 SO 4 H2O2H2O2 O3O3 PANs MostandsaltsNO 3 – Mobile SO 4 2 – Which chemicals lower the pH of rain?
Primary Pollutants Secondary Pollutants SourcesNatural Stationary COCO 2 SO 2 NONO 2 Most hydrocarbons Most suspended particles SO 3 HNO 3 H 2 SO 4 H2O2H2O2 O3O3 PANs MostandsaltsNO 3 – Mobile SO 4 2 – Secondary Pollutants in RED
pH levels of US soil
Effects of Acid Rain Decrease soil pH (more acidic) Decrease pH of rivers, lakes, ponds, etc Fish kills Lung/respiratory problems Degrade metal pipes, leading to water pollution Plants become susceptible to disease, parasites, etc
Reduce air pollution by improving energy efficiency Reduce coal use Increase natural gas use Increase use of renewable resources Burn low-sulfur coal Remove SO 2 particulates, and No x from smokestack gases Remove No x from motor vehicular exhaust Tax emissions of SO 2 Add lime to neutralize acidified lakes Add phosphate fertilizer to neutralize acidified lakes Acid Rain Prevention and Solution Solutions Acid Deposition Prevention Cleanup
20.5 Indoor Air Pollution
Go outside and play Indoor air is typically a greater threat People are inside up to 98% of their time Less air flow to remove pollutants Top pollutants: cigarette smoke, formaldehyde, radon, particulate matter. Sick building Typically newer buildings because of less air leaks. Symptoms: headache, coughing, sneezing, tiredness.
Formaldehyde Found in: plywood, furniture, upholstery, floor adhesives, dry cleaning chemicals. Causes: breathing problems, headache, sore throat, dizziness, eye irritation in those sensitive to low levels. Chronic exposure to higher levels can lead to cancer. Radon Naturally occurring from radioactive decay of U-238. Occurs in soils, bedrock and can get into homes through cracks. Cant get out and builds up Can lead to lung cancer
Chloroform: chlorine- treated hot water; cancers Para-dichlorobenzene: air fresheners, moth balls; cancers Tetrachloroethylene: dry cleaning residue; nerve, liver, kidney problems Formaldehyde: from processed wood; eye, nose, throat, lung irritant Benzo- -pyrene: from smoke; lung cancer Styrene: from carpet/plastic. Kidney/liver problems Radon- 222: from soils, lung disease Methylene Chloride: paint stripper, thinner; nerve, diabetes Tobacco Smoke Carbon Monoxide Asbestos: old floor tile, Pipe insulation; lung problems, cancer Nitrogen Oxides: Gas ovens, kerosene heaters, un-vented gas burning; lung irritation, headaches 1, 1, 1- Trichloroethane: aerosals; dizziness, irregular breathing
Solutions Indoor Air Pollution PreventionCleanup Cover ceiling tiles and lining of AC ducts to prevent release of mineral fibers Ban smoking or limit it to well- ventilated areas Set stricter formaldehyde emissions standards for carpet, furniture, and building materials Prevent radon infiltration Use office machines in well- ventilated areas Use less polluting substitutes for harmful cleaning agents, paints, and other products Use adjustable fresh air vents for work spaces Increase intake of outside air Change air more frequently Circulate buildings air through rooftop greenhouses Use exhaust hoods for stoves and appliances burning natural gas Install efficient chimneys for wood-burning stoves
Particulates - Aka: particulate matter (PM) What are they? aerosols or fine particles, are tiny particles of solid (a smoke) or liquid (an aerosol) suspended in a gas. Size: 100 µm in diameter. Who do they effect? Sensitive populations such as children, the elderly, and individuals suffering from respiratory disease.
Particulate Matter (PM) Larger particles are generally filtered in the nose and throat and do not cause problems. PM smaller than about 10 µm, referred to as PM 10, can settle in the bronchi and lungs and cause health problems.
Particulate Matter (PM) Includes a wide range of pollutants – –road dust – diesel soot – fly ash – wood smoke – sulfate aerosols (suspended as particles in the air) These particles are a mixture of visible and microscopic solid particles and minute liquid droplets known as aerosols.
Take a deep breath… Asthma: on the rise! WHY?? Varying opinions: Overly sterile environment as children; dont build up natural immunity Exposure to allergens Genetic make up Exposure to pollution Lung cancer Chronic bronchitis Emphysema
National Ambient Air Quality Standards (NAAQS) Standards established by the EPA that apply for outdoor air throughout the country. Primary standards are designed to protect human health. Secondary standards are designed to protect public welfare (e.g. building facades, visibility, crops, and domestic animals).
EPAs watchful eye NAAQS requires the EPA to set standards on six criteria pollutants: 1.Ozone (O 3 ) 2.Particulate Matter 3.Carbon monoxide (CO) 4.Sulfur dioxide (SO 2 ) 5.Nitrogen oxides (NO x ) 6.Lead (Pb)
Temperature Inversions (pg. 442) and Heat Islands (online activity)
Warmer air Inversion layer Cool layer Mountain Valley Decreasing temperature Increasing altitude Temperature Inversion Traps pollutants near surface. Mountains prevent wind in area and shadow sun to keep lower air cool.
Inversion layer Mountain range Sea breeze Descending warm air mass Decreasing temperature Increasing altitude Temperature Inversion Traps pollutants near surface. Mountains prevent pollutants leaving. Sea breeze blows in, not out This is what is happening in LA. Video clipVideo clip
20.7 Preventing and Reducing Air Pollution
Solutions Stationery Source Air Pollution Prevention Dispersion or Cleanup Burn low-sulfur coal Remove sulfur from coal Convert coal to a liquid or gaseous fuel Shift to less polluting fuels Disperse emissions above thermal inversion layer with tall smokestacks Remove pollutants after combustion Tax each unit of pollution produced
Out-put or Control Methods See text pg. 457 Fig 20-18
Electrostatic Precipitator – static plates collect particles Dirty gas Dust discharge Electrodes Cleaned gas
Dirty gas Baghouse Filter – only one to remove hazardous fine particles Dust discharge Bags
Dirty gas Dirty water Clean water Wet Scrubber – Expensive Wet gas Cleaned gas Remove 98% of SO2 and PM from emissions
Cyclone Separator - Cheap Dirty gas Dust discharge Cleaned gas Does NOT produce hazardous materials like other
Solutions Motor Vehicle Pollutions Prevention Cleanup Mass transit Bicycles and walking Less polluting engines Less polluting fuels Improve fuel efficiency Get older, polluting cars off the road Give buyers tax write- offs for buying low- polluting, energy- efficient vehicles Restrict driving in polluted areas Emission control devices Car exhaust Inspections twice a year Stricter emission standards Solutions for mobile emissions
Solutions Air Pollution PreventionCleanup Improve energy efficiency to reduce fossil fuel use Rely more on lower- polluting natural gas Rely more on renewable energy (especially solar cells, wind, and solar- produced hydrogen) Transfer technologies for latest energy efficiency, renewable energy, and pollution prevention to developing countries. Reduce poverty Distribute cheap and efficient cookstoves to poor families in developing countries Reduce or ban indoor smoking Develop simple and cheap test for indoor pollutants such as particulates, radon, and formaldehyde
Clean Air Acts US Congress in 1970, 1977, 1990 EPA regulation of emissions that contribute to global warming, ozone depletion and air pollution. View clipView clip You should read ALL case studies in the chapter! Ea: The Bad Old Days, A Burning Controversy and section 20-7 specifically.
VI. Pollution (25-30%) Air pollution 1.Sources-primary and secondary (20.2 & air pollution lab) 2.major air pollutants (20.2 & pollutant chart) 3.measurement units (air pollution lab & emissions trading game) 4.smog (20.3 & Demo: Smog in a jar) 5.acid deposition-causes and effects (20.4, pH/acid rain lab, video) 6.heat islands (online activity) and temperature inversions (20.3) 7.indoor air pollution (20.5 & air particulate lab) 8.remediation and reduction strategies (air pollution allowance trading article, emissions trading game) and Fig ) 9.Clean Air Act and other relevant laws (Law sheet, NAAQS)