Air Pollution Chapter 18 Dr Wesam Al Madhoun

Air Pollution Chapter 18 Dr. Wesam Al Madhoun

Core Case Study: South Asia’s Massive Brown Cloud § Asian Brown Cloud • Causes • Chemical composition • Areas impacted § Air pollution connects the world § Steps taken in China and India to reduce air pollution

The Asian Brown Cloud

Air Pollution in Shanghai, China, in 2004

18 -1 What Is the Nature of the Atmosphere? § Concept 18 -1 The atmosphere is structured in layers, including the troposphere, which supports life, and the stratosphere, which contains the protective ozone layer.

The Atmosphere Consists of Several Layers § Atmosphere varies in • Density • Atmospheric pressure

Air Movements in the Troposphere Play a Key Role in Earth’s Weather and Climate § Troposphere • • 75– 80% of the earth’s air mass Closet to the earth's surface Chemical composition of air Rising and falling air currents: weather and climate • Involved in chemical cycling

The Stratosphere Is Our Global Sunscreen § Stratosphere • Similar composition to the troposphere, with 2 exceptions • Much less water • O 3, ozone layer, filters UV • Location

120 Atmospheric pressure (millibars) 1, 000 200 400 600 800 75 0 110 100 90 Temperature Thermosphere 65 Mesopause 55 Mesosphere 70 60 Stratopause 45 35 50 Stratosphere 40 30 25 Tropopause Ozone layer 20 10 Pressure (Sea 0 level) Altitude (miles) Altitude (kilometers) 80 – 80 Troposphere 80 40 – 40 0 Temperature (˚C) 120 15 5 Pressure = 1, 000 millibars at ground level Fig. 18 -3, p. 470

18 -2 What Are the Major Outdoor Pollution Problems? § Concept 18 -2 Pollutants mix in the air to form industrial smog, mostly the result of burning coal, and photochemical smog, caused by motor vehicle, industrial, and power plant emissions.

Air Pollution Comes from Natural and Human Sources (1) § Air pollution § Natural sources • • Dust blown by wind Pollutants from wildfires and volcanoes Volatile organics released by plants Withdrawing groundwater

Case Study: Air Pollution in the Past: The Bad Old Days (1) § Discovery of fire § Middle Ages § Industrial Revolution § London, England • 1850 s • 1952: yellow fog • Clean Air Act of 1956

Case Study: Air Pollution in the Past: The Bad Old Days (2) § United States • 1948: Donora, PA; first U. S. air pollution disaster • 1963: New York City § Global problem

Some Pollutants in the Atmosphere Combine to Form Other Pollutants § Primary pollutants § Secondary pollutants § Air quality improving in developed countries § Much more needs to be done in developing countries • Indoor pollution: big threat to the poor

Primary Pollutants CO CO 2 SO 2 NO NO 2 Most hydrocarbons Most suspended particles Secondary Pollutants SO 3 HNO 3 H 2 SO 4 H 2 O 2 O 3 PANs Most NO 3− and SO 42− salts Sources Natural Stationary Mobile Fig. 18 -4, p. 472

What Are the Major Outdoor Air Pollutants? (1) § Carbon oxides • • Carbon monoxide (CO) Carbon dioxide (CO 2) Sources Human health and environmental impact

What Are the Major Outdoor Air Pollutants? (2) § Nitrogen oxides (NO) and nitric acid (HNO 3) • • Sources Acid deposition Photochemical smog Human health and environmental impact § Sulfur dioxide (SO 2) and sulfuric acid (H 2 SO 4) • Sources • Human health and environmental impact

What Are the Major Outdoor Air Pollutants? (3) § Particulates • Suspended particulate matter (SPM) • Fine • Ultrafine • Sources • Human health and environmental impact

What Are the Major Outdoor Air Pollutants? (4) § Ozone (O 3) • Sources • Human and environmental impact § Volatile organic compounds (VOCs) • Hydrocarbons and terpenes • Sources • Human and environmental impact

Chemical Reactions That Form Major Outdoor Air Pollutants

Stepped Art Table 18 -1, p. 473

Statue Corroded by Acid Deposition and Other Forms of Air Pollution, RI, U. S.

Science Focus: Detecting Air Pollutants § Chemical instruments § Satellites § Nanotechnology § Biological indicators • Lichens

Natural Capital: Lichen Species, Vulnerability to Air Pollutants

Case Study: Lead Is a Highly Toxic Pollutant (1) § Does not break down in the environment § Sources § Human health and environmental impact • Most vulnerable

Case Study: Lead Is a Highly Toxic Pollutant (2) § Reduction of lead (Pb) • Unleaded gasoline • Unleaded paint § Still problems • 2007: toys with Pb paint recalled • Global ban on lead in gasoline and paint

SOLUTIONS Lead Poisoning Prevention Control Phase out leaded gasoline worldwide Replace lead pipes and plumbing fixtures containing lead solder Phase out waste incineration Remove leaded paint and lead dust from older houses and apartments Ban use of lead solder Ban lead glazing for ceramicware used to serve food Sharply reduce lead emissions from incinerators Remove lead from TV sets and computer monitors before incineration or land disposal Ban candles with lead cores Test for lead in existing ceramicware used to serve food Test blood for lead by age 1 Test existing candles for lead Ban use of lead in computer and TV monitors Wash fresh fruits and vegetables Fig. 18 -7, p. 476

Burning Coal Produces Industrial Smog § Chemical composition of industrial smog § Reduction of this smog in urban cities of the United States § China and smog • Human deaths

Ammonium sulfate [(NH 4)2 SO 4] Ammonia (NH 3) Sulfuric acid (H 2 SO 4) Water vapor (H 2 O) Sulfur trioxide (SO 3 ) Carbon monoxide (CO) and carbon dioxide (CO 2) Oxygen (O 2) Sulfur dioxide (SO 2) Burning coal and oil Oxygen (O 2) Sulfur (S) in coal and oil Carbon (C) in coal and oil Stepped Art Fig. 18 -8, p. 476

Sunlight Plus Cars Equals Photochemical Smog § Photochemical Smog • Chemical composition • Sources § VOCs + NO 2 + Heat + Sunlight yields • Ground level O 3 and other photochemical oxidants • Aldehydes • Other secondary pollutants § Human health and environmental impact

PANS and other pollutants Volatile organic compounds (VOCs) Ozone (O 3) Oxygen (O 2) Nitric oxide (NO) + Oxygen atom (O) Water vapor Hydrocarbons (H O) UV radiation 2 Peroxyacyl nitrates Nitrogen dioxide (NO 2) (PANs) Oxygen (O 2) Nitric oxide (NO) Oxygen (O 2) Burning fossil fuels Nitrogen (N) in fossil fuel Fig. 18 -9, p. 477

Global Outlook: Photochemical Smog in Santiago, Chile

Denver’s Brown Cloud: http: //www. infrastructurist. com/wp-content/uploads/brown-cloud. jpg

Several Factors Can Decrease or Increase Outdoor Air Pollution (1) § Outdoor air pollution may be decreased by • • • Settling of particles due to gravity Rain and snow Salty sea spray from the ocean Winds Chemical reactions

Several Factors Can Decrease or Increase Outdoor Air Pollution (2) § Outdoor air pollution may be increased by • • • Urban buildings Hills and mountains High temperatures Emissions of VOCs from certain trees and plants Grasshopper effect Temperature inversions

Descending warm air mass Warmer air Inversion layer Sea breeze Increasing altitude Decreasing temperature Fig. 18 -11, p. 478

18 -3 What Is Acid Deposition and Why Is It a Problem? § Concept 18 -3 Acid deposition is caused mainly by coal-burning power plant and motor vehicle emissions, and in some regions, threatens human health, aquatic life and ecosystems, forests, and human-built structures.

Acid Disposition Is a Serious Regional Air Pollution Problem § Acid deposition, acid rain • • • Formation Local versus regional problems Effects of prevailing winds Buffers Where is the worst acid deposition?

Wind Transformation to sulfuric acid (H 2 SO 4) and nitric acid (HNO 3) Nitric oxide (NO) Windborne ammonia gas and some soil particles partially neutralize acids and form dry sulfate and nitrate salts Sulfur dioxide (SO 2) and NO Acid fog Dry acid deposition (sulfur dioxide gas and particles of sulfate and nitrate salts) Wet acid depostion (droplets of H 2 SO 4 and HNO 3 dissolved in rain and snow) Lakes in shallow Lakes in deep soil low in soil high in limestone are become acidic buffered Fig. 18 -12, p. 479

Potential problem areas because of sensitive soils Potential problem areas because of air pollution: emissions leading to acid deposition Current problem areas (including lakes and rivers) Fig. 18 -13, p. 480

Acid Deposition Has a Number of Harmful Effects (1) § Human respiratory disorders § Aquatic ecosystems affected § Release of toxic metals

Acid Deposition Has a Number of Harmful Effects (2) § Leaching of soil nutrients § Loss of crops and trees § Damage to buildings, statues, and monuments

Emissions NOx SO 2 Acid HO deposition 2 2 O 3 PANs Others Direct damage to leaves and bark Reduced photosynthesis and growth Soil acidification Leaching of soil nutrients Acids Release of toxic metal ions Increased susceptibility to drought, extreme cold, insects, mosses, and disease organisms Tree death Root damage. Reduced nutrient and water uptake Lake Groundwater Fig. 18 -14 a, p. 481

Science Focus: Hubbard Brook Study Effects of Acid Rain § White Mountains, NH, U. S. § Experimentation supports: • Trees do not suffer from direct contact with acid rain • Nutrients are leached out of the soil • Effect of Ca 2+ on regrowth of the forest

We Know How to Reduce Acid Deposition § Prevention approaches § Clean up • Add lime to neutralize acidified lakes and soil • Add phosphate fertilizer to neutralize acidified lakes

SOLUTIONS Acid Deposition Prevention Cleanup Reduce coal use Add lime to neutralize acidified lakes Burn low-sulfur coal Increase natural gas use Increase use of renewable energy resources Add phosphate fertilizer to neutralize acidified lakes Remove SO 2 particulates and NOx from smokestack gases Remove NOx from motor vehicular exhaust Tax emissions of SO 2 Reduce air pollution by improving energy efficiency Fig. 18 -15, p. 483

Indoor Air Pollution

18 -4 What Are the Major Indoor Air Pollution Problems? § Concept 18 -4 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 Is a Serious Problem (1) § Developing countries • Indoor burning • Poor suffer the greatest risk § Developed countries • Indoor air pollution is greater than outdoor air pollution

Indoor Air Pollution Is a Serious Problem (2) § Why? • 11 of the common air pollutants higher inside than outside • Greater in vehicles than outside • Health risks magnified: people spend 70– 98% of their time is indoors

Indoor Air Pollution Is a Serious Problem (3) § Who are at greatest risk from indoor air pollution? • • Children under 5 and the elderly Sick Pregnant women People with respiratory disorders or heart problems • Smokers • Factory workers

Indoor Air Pollution Is a Serious Problem (4) § Four most dangerous indoor air pollutants • • Tobacco smoke Formaldehyde Radioactive radon-222 gas Very small particles § Sources of these pollutants § Human health risks

Indoor Air Pollution Is a Serious Problem (5) § Other possible indoor air pollutants • Pesticide residue • Pb particles • Living organisms and their excrements • E. g. , Dust mites and cockroach droppings • Airborne spores of molds and mildews § Sick-building syndrome

Some Important Indoor Air Pollutants

Science: Magnified View of a Household Dust Mite in a Dust Ball

Case Study: Radioactive Radon Gas § Sources § Human health risks § Testing for radon § Correcting a radon problem

Outlet vents for furnaces and dryers Open window Cracks in wall Openings around pipes Slab joints Wood stove Cracks Clothes in floor Furnace dryer Slab Radon-222 gas Sump pump Uranium-238 Soil Fig. 18 -18, p. 485

18 -5 What Are the Health Effects of Air Pollution? § Concept 18 -5 Air pollution can contribute to asthma, chronic bronchitis, emphysema, lung cancer, heart attack, and stroke.

Your Body’s Natural Defenses against Air Pollution Can Be Overwhelmed § Respiratory system protection from air pollutants • Role of cilia, mucus, sneezing, and coughing § Effect of smoking and prolonged air pollution exposure • Chronic bronchitis • Emphysema

Major Components of the Human Respiratory System

Normal Human Lungs and the Lungs of a Person Who Died of Emphysema

Air Pollution Is a Big Killer § 3 Million deaths per year world-wide • Mostly in Asia • Main causes § EPA: proposed stricter emission standards for diesel-powered vehicles § Link between international trade and air pollution • Cargo ships and pollution

Premature Deaths from Air Pollution in the U. S.

18 -6 How Should We Deal with Air Pollution? § Concept 18 -6 Legal, economic, and technological tools can help to clean up air pollution, but much greater emphasis should be focused on preventing air pollution.

Laws and Regulations Can Reduce Outdoor Air Pollution (1) § United States • Clean Air Acts: 1970, 1977, and 1990 § EPA • National ambient air quality standards (NAAQs) for 6 outdoor criteria pollutants • National emission standards for 188 hazardous air pollutants (HAPs) • Toxic Release Inventory (TRI)

Laws and Regulations Can Reduce Outdoor Air Pollution (2) § Good news in U. S. • Decrease in emissions • Use of low-sulfur diesel fuel • Cuts pollution § Developing countries • More air pollution

Case Study: U. S. Air Pollution Can Be Improved (1) § Rely on cleanup more than prevention of pollution § Raise fuel-efficiency for cars, SUVs, and light trucks § Better regulation of emissions of motorcycles and two-cycle gasoline engines § Regulate air pollution for oceangoing ships in American ports

Case Study: U. S. Air Pollution Can Be Improved (2) § Why are airports exempt from many regulations? § Regulate greenhouse gas emissions § Ultrafine particles are not regulated § Urban O 3 levels too high

Case Study: U. S. Air Pollution Can Be Improved (3) § What about indoor air pollution? § Better enforcement of the Clean Air Acts § Is intense pressure needed from citizens to make improvements?

We Can Use the Marketplace to Reduce Outdoor Air Pollution § Emission trading or cap-and-trade program • Mixed reactions to program • SO 2 emissions down significantly • NO 2 will be tried in the future

There Are Many Ways to Reduce Outdoor Air Pollution § 1980 – 2006 • SO 2 emissions from U. S. electric power plants decreased by 66% • NOx emissions by 41% • Particulate emissions by 28% § Older plants not governed by the same regulations § New cars have better emissions

SOLUTIONS Stationary Source Air Pollution Prevention Burn low-sulfur coal Remove sulfur from coal Convert coal to a liquid or gaseous fuel Shift to less polluting energy sources Dispersion or Cleanup Disperse emissions above thermal inversion layer with tall smokestacks Remove pollutants after combustion Tax each unit of pollution produced Fig. 18 -22, p. 491

SOLUTIONS Motor Vehicle Air Pollution Prevention Use mass transit Walk or bike Cleanup Require emission control devices Use less polluting fuels Improve fuel efficiency Get older, polluting cars off the road Give large tax writeoffs or rebates for buying low-polluting, energy efficient vehicles Inspect car exhaust systems twice a year Set strict emission standards Fig. 18 -23, p. 491

Reducing Indoor Air Pollution Should Be a Priority § Greater threat to human health than outdoor pollution § What can be done? • Prevention • Cleanup

SOLUTIONS Prevention Indoor Air Pollution Cleanup or Dilution Clean ceiling tiles and line 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 a building’s air through rooftop greenhouses Use efficient venting systems for woodburning stoves Use exhaust hoods for stoves and appliances burning natural gas Fig. 18 -24, p. 492

What Can You Do? Indoor Pollution: Ways to Reduce Your Exposure

We Need to Put More Emphasis on Pollution Prevention § Output approaches § New shift to preventing outdoor and indoor pollution • Pressure from citizens

SOLUTIONS Air Pollution Outdoor Indoor Improve energy efficiency to reduce fossil fuel use Reduce poverty Rely more on lowerpolluting natural gas Distribute cheap and efficient cookstoves or solar cookers to poor families in developing countries Rely more on renewable energy (especially solar cells, wind, and solarproduced hydrogen) Reduce or ban indoor smoking Transfer energy efficiency, renewable energy, and pollution prevention technologies to developing countries Develop simple and cheap tests for indoor pollutants such as particulates, radon, and formaldehyde Fig. 18 -26, p. 493