Ch 20 Air Pollution The Atmosphere Troposphere 78

Ch. 20 Air Pollution

The Atmosphere Ø Troposphere Ø 78% N, 21% O Ø Stratosphere Ø Ozone layer Fig. 20 -2 p. 434

Outdoor Air Pollution Ø Primary pollutants Ø Secondary pollutants

Photochemical Smog Ø Brown-air smog Ø Gray Smog Ø Photochemical oxidants Fig. 20 -5 p. 440

Temperature Inversions Ø Utah’s Air Quality division Fig. 20 -7 p. 443 Thermal inversion

Regional Outdoor Air Pollution from Acid Deposition Ø Acid deposition- wet and dry Fig. 20 -8 p. 444

Acid Deposition in the US Fig. 20 -9 p. 445

Acid Deposition Effects Ø Respiratory diseases Ø Toxic metal leaching Ø Damage to structures, especially containing calcium carbonate Ø Decreased visibility Fish declines

Emission Acid deposition SO 2 H 2 O 2 PANs NOX O 3 Others Reduced photosynthesis and growth Direct damage to leaves and bark Increased Susceptibility to drought, extreme cold, insects, mosses, and disease organisms Soil acidification Leaching of Soil nutrients Groundwater Acid Tree death Release of toxic metal ions Root damage Reduced nutrient and water uptake

Indoor Air Pollution Fig. 20 -13 p. 450

Effects of Air Pollution on People Ø Respiratory diseases (see Fig. 20 -15 p. 452) Ø Asthma Ø Lung cancer Ø Chronic bronchitis Ø Emphysema Ø Premature death

Solutions: Preventing and Reducing Air Pollution Ø Clean Air Act Ø National Ambient Air Quality Standards (NAAQS) Ø Emissions trading

Emission Reduction Fig. 20 -17 p. 456 Fig. 20 -18 a p. 457

Chapter 21 Climate Change and Ozone Loss

Past Climate Changes Ø Past global temperatures Ø Recent trends in global temperatures Fig. 21 -2 p. 463

How Scientists Monitor Climate change Ocean sediment cores • Fossils of plankton • Isotopes of various chemicals • Depths of different layers/particle size Fossil record • Fossil pollen • Fossil flora • Fossil fauna Tree cores Ice cores • Isotopes of oxygen in ice (related to temperature) • C 02 concentrations Sea Level Changes

Major Greenhouse Gases Water vapor & Carbon Dioxide (highest concentrations), as well as CFCs, Ozone, Methane, Nitrous Oxide (N 2 O) These gases absorb infrared radiation. CO 2 = Fossil fuels Deforestation CFC/ HCFC/HFC = Anthropogenic only Air Conditioners, refrigerators *use to be the major propellant of aerosol sprays CH 4 = Burning biomass, production of Coal and natural gas Ag. Activities (anaerobic decomposition) N 2 O = Fertilizers Burning of fossil fuels, livestock wastes, nylon products CFC and methane accumulate faster than CO 2. CFC’s stay in the stratosphere longer.

Factors Affecting the Earth’s Temperature Ø Changes in solar output Ø Changes in Earth’s albedo (ability of white ice caps to reflect 80 -90% of incoming sunlight) Ø Moderating effect of oceans Ø Clouds and water vapor Ø Air pollution

Courtesy of http: //topex-www. jpl. nasa. gov/education/images/oc_heat. gif

Climate Change and Human Activities Ø Increased use of fossil fuels Ø Deforestation Ø Global warming Ø Melting icecaps and glaciers Ø Rising sea level

Possible Benefits from a Warmer Atmosphere (depending on where you live) Ø Less severe winters Ø More precipitation in some dry areas Ø Less precipitation in some wet areas Ø Increased food production in some areas Ø Expanded population and ranges of some species (spruce bark beetle) Refer to Fig. 21 -13 p. 476

Some Possible Effects of a Warmer World GLOBAL EFFECTS of Climate change

Solutions: Dealing with the Threat of Climate Change Fig. 21 -16 p. 479 Options Ø Do nothing Ø Do more research Ø Act now to reduce risks Ø Precautionary principle

Oil rig Coal power plant Tanker delivers CO 2 from plant to rig Tree plantation CO 2 is pumped down from rig for deep ocean disposal Abandoned oil field Switchgrass Crop field CO 2 is pumped down to reservoir through abandoned oil field Spent oil reservoir is used for CO 2 deposit = CO 2 pumping

Reducing Greenhouse Gas Emissions Ø Kyoto Treaty (1997) – 39 countries agreed to reduce their greenhouse gas emissions; by 2004 it included more than 120 countries! Ø U. S. withdraws from Kyoto Treaty (2001)- controversial Ø Other reductions in CO 2 – schools, businesses, and homes converting to use of more energy efficient products Refer to Fig. 21 -18 p. 483

Global Warming vs. Ozone Depletion Global warming § Involves troposphere § Substances involved: greenhouse gases that trap heat (CO 2, CH 4, N 2 O) § Problem: burning of FF, deforestation increase trapping of heat and increase Earth’s temp. § Consequences: changes in climate, agric. productivity, H 2 O supplies, and sea level § Responses: decrease fossil fuel use and deforestation; prepare for climate change Ozone Depletion § Involves stratosphere § Substances involved: O 3, O 2, CFC’s § Problem: human activities and CFC’s destroy ozone allowing more UV radiation to reach Earth § Consequences: increase skin cancer, cataracts, damage to crops/phytoplankon § Responses: Eliminate/substitute for CFC’s and ODC’s

Ozone • Stratospheric Ozone – good thing! 97% of all UV absorbed by 03 • Formed from O 2 – life driven

Former Uses of CFCs Ø Air Conditioners Ø Refrigerators Ø Spray cans Ø Cleaners for electronic parts Ø Sterilizing medical instruments Ø Fumigants for granaries and cargo ships

Ultraviolet light hits a chlorofluorocarbon (CFC) molecule, such as CFCl 3, breaking off a chlorine atom and leaving CFCl 2. Sun Cl Cl C F Cl UV radiation Once free, the chlorine atom is off to attack another ozone molecule and begin the cycle again. movie Cl Cl O The chlorine atom attacks an ozone (O 3) molecule, pulling an oxygen atom off it and leaving O O O an oxygen molecule (O 2). Cl Summary of Reactions CCl 3 F + UV Cl + CCl 2 F Cl + O 3 Cl. O + O 2 Repeated Cl + O 2 many times O A free oxygen atom pulls the oxygen atom off the chlorine monoxide Cl molecule to form O 2. O O Cl The chlorine atom and the O oxygen atom join O to form a chlorine monoxide molecule O (Cl. O).

Seasonal Ozone Layer Thinning at the Poles Ø Ozone thinning (hole) Ø Polar vortex

http: //www. epa. gov/ozone/science/hole/size. html

Effects of Ozone Depletion Human Health • Worse sunburns • More eye cataracts • More skin cancers • Immune system suppression Food and Forests • Reduced yields for some crops • 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 CO 2 from atmosphere by phytoplankton and CFCs acting as greenhouse gases

Solutions: Protecting the Ozone Layer Ø CFC substitutes Ø Montreal Protocol- 1987 limits/ bans CFC’s ; production stopped in 1995; India and China not a part of the treaty Ø Copenhagen Protocol Fig. 21 -25 p. 489