Ch. 20 Air Pollution

Layers of the Atmosphere Fig. 20-2 p. 434 Troposphere- layer closest to Earth; 78% N, 21% O Stratosphere = “sunscreen” thinning ozone layer (3O2+UV -> 2O3) due to CFC’s

Outdoor Air Pollution Primary pollutants Secondary pollutants

Effects

Air Quality Index (AQI) Real Time Data - by location

Smog – 2 TYPES Industrial Smog Burning coal; soot, CO, CO2 (Gray Smog) China; NYC, India London during Industrial Revolution 1952 Burning coal; soot, CO, CO2 Mercury and sulfur – sulfur oxides

Smog – 2 TYPES Photochemical Smog (Brown smog) Fig. 20-5 p. 440 Mexico City Los Angeles, CA Photochemical oxidants nitrous oxides Fig. 20-5 p. 440 Low level Ozone (Tropo.)

Temperature Inversions Thermal inversion – how it forms and increases potential for consistent photochemical smog Fig. 20-7 p. 443

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

Acid Deposition in the US Fig. 20-9 p. 445 Remember Limestone lab! High levels of calcium carbonate in soil helps neutralize the effects of acid rain!

Acid Deposition Effects Respiratory diseases Metal leaching –Al ions (toxic)in soil; Mg ions loss for plant uptake (non-toxic) Damage to structures, especially containing calcium carbonate Decreased visibility Fish declines Coral bleaching

Emission Acid deposition SO2 H2O2 PANs NOX O3 Others Increased Susceptibility to drought, extreme cold, insects, mosses, and disease organisms Direct damage to leaves and bark Reduced photosynthesis and growth Soil acidification Tree death Leaching of Soil nutrients Release of toxic metal ions Root damage Reduced nutrient and water uptake Acid Groundwater

Indoor Air Pollution Fig. 20-13 p. 450

Effects of Air Pollution on People Respiratory diseases (see Fig. 20-15 p. 452) Asthma Air purifiers – Consumer Reports best for removing small particulates (allergies) Lung cancer Chronic bronchitis Emphysema Premature death

Solutions: Preventing and Reducing Air Pollution Clean Air Act (1970, amended 1990) National Ambient Air Quality Standards (NAAQS) Emissions trading Cleaning technologies: Electrostatic precipitators (electrodes; particulates) Scrubbers (sulfur dioxides =smoke stacks=coal) Cleaning coal to remove sulfur before burning

Clean Air Act 1970 Set stricter standards to air quality Imposed emissions limits Funds for pollution control research amended include reduction in vehicle emission; catalytic converter technology (reduced 98% of 1960’s vehicle emissions) and Clean Air Facts of vehicle technology 1990 Strengthened air quality standards Emission trading program for SO2

(See minimum levels on EPA website) EPA Standards (NAAQS) 6 Main “Criteria” Pollutants: Carbon monoxide (CO) Sulfur dioxide (SO2) Nitrogen dioxide (NO2) Tropospheric ozone (O3) Particulate Matter (PM10, PM2.5) Lead (Pb) *Volatile Organic Compounds (VOCs)- hydrocarbons from burning methane, propane, butane (See minimum levels on EPA website)

More serious health risks! Particulate Matter More serious health risks!

Particulate Matter Collectors

Emission Reduction - Scrubbers = smoke stacks of coal plants Fig. 20-18a p. 457

Climate Change and Ozone Loss Chapter 21 Climate Change and Ozone Loss

Past Climate Changes Past global temperatures 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) C02 concentrations Sea Level Changes

Major Greenhouse Gases Water vapor Carbon Dioxide (highest concentrations) CFCs (Chlorofluorocarbons) Ozone (O3) Methane (CH4) Nitrous Oxide (N2O) These gases absorb infrared radiation. CH4 = Burning biomass, production of Coal and natural gas Ag. Activities (anaerobic decomposition) CFC/ HCFC/HFC = Anthropogenic only Air Conditioners, refrigerators *use to be the major propellant of aerosol sprays CO2 = Fossil fuels Deforestation N2O = Fertilizers Burning of fossil fuels, livestock wastes, nylon products CFC and methane accumulate faster than CO2. CFC’s stay in the stratosphere longer.

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

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

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

Possible Benefits from a Warmer Atmosphere (depending on where you live) Less severe winters More precipitation in some dry areas Less precipitation in some wet areas Increased food production in some areas 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 Do nothing Do more research Act now to reduce risks Precautionary principle

through abandoned oil field Coal power plant Tanker delivers CO2 from plant to rig Oil rig Tree plantation CO2 is pumped down from rig for deep ocean disposal Abandoned oil field Switchgrass Crop field CO2 is pumped down to reservoir through abandoned oil field Spent oil reservoir is used for CO2 deposit = CO2 deposit = CO2 pumping

Reducing Greenhouse Gas Emissions Kyoto Treaty (1997) – 39 countries agreed to reduce their greenhouse gas emissions; by 2004 it included more than 120 countries! U.S. withdraws from Kyoto Treaty (2001)- controversial Other reductions in CO2 – schools, businesses, and homes converting to use of more energy efficient products Refer to Fig. 21-18 p. 483

Global Warming vs. Ozone Depletion Involves troposphere Substances involved: greenhouse gases that trap heat (CO2, CH4, N2O) Problem: burning of FF, deforestation increase trapping of heat and increase Earth’s temp. Consequences: changes in climate, agric. productivity, H2O supplies, and sea level Responses: decrease fossil fuel use and deforestation; prepare for climate change Ozone Depletion Involves stratosphere Substances involved: O3, O2, 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 O2 – life driven

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

movie Ultraviolet light hits a chlorofluorocarbon (CFC) molecule, such as CFCl3, breaking off a chlorine atom and leaving CFCl2. Sun Cl Cl C Once free, the chlorine atom is off to attack another ozone molecule and begin the cycle again. Cl F UV radiation movie Cl Cl O O A free oxygen atom pulls the oxygen atom off the chlorine monoxide molecule to form O2. The chlorine atom attacks an ozone (O3) molecule, pulling an oxygen atom off it and leaving an oxygen molecule (O2). Cl Cl O O O O O The chlorine atom and the oxygen atom join to form a chlorine monoxide molecule (ClO). Cl O Summary of Reactions CCl3F + UV Cl + CCl2F Cl + O3 ClO + O2 Cl + O Cl + O2 Repeated many times O O

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

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

Effects of Ozone Depletion 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 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 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

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