Presentation on theme: "Air Pollution, Climate Disruption, and Ozone Depletion Chapter 15."— Presentation transcript:
Air Pollution, Climate Disruption, and Ozone Depletion Chapter 15
WHAT IS THE NATURE OF THE ATMOSPHERE?
The atmosphere consists of several layers –The troposphere miles above sea level –The stratosphere 11 to 30 miles above the earth’s surface –Ozone (O 3 ) layer, found roughly 11–19 miles above sea level.
Air pollution comes from natural and human sources –Primary pollutants are harmful chemicals emitted directly into the air from natural processes and human activities. –Secondary pollutants react with one another and with other normal components of air to form new harmful chemicals, called secondary pollutants.
Fig. 15-3, p. 377 Primary Pollutants CO CO 2 Secondary Pollutants SO 2 NO CH 4 and most other hydrocarbons CH 4 and most other hydrocarbons SO 3 Most suspended particles H2O2H2O2 H2O2H2O2 H 2 SO 4 PANs Most NO 3 – and SO 4 2– salts Natural Source Stationary Human Source Mobile NO 2 O3O3 O3O3 HNO 3
What are the major outdoor air pollutants? Primary sources –Carbon oxides –Carbon dioxides –Nitrogen oxides –Nitrogen dioxides –Sulfur dioxides –Particulates (SPM) Secondary sources –H 2 SO 4 (aerosols) –Nitric and sulfate salts –Ozone –VOC’s
Sunlight plus cars equals photochemical smog Photochemical smog is a mixture of primary and secondary pollutants & UV radiation from the sun. (Inversion Layer)
Acid deposition, which consists of rain, snow, dust, or gas with a pH lower than 5.6, is commonly called acid rain
Current and potential regions where acid deposition is a problem
pH Scale Acid Base
Numerous indoor air pollutants are found in most modern homes
We can use the marketplace to reduce outdoor air pollution Allow producers of air pollutants to buy and sell government air pollution shares in the marketplace. The Clean Air Act of 1990 authorized an emissions trading, or cap-and-trade, program, enabled coal- burning power plants to buy and sell SO 2 pollution rights. –Each plant is annually given a number of pollution credits, which allow it to emit a certain amount of SO 2. –A utility that emits less than its allotted amount has a surplus of pollution credits which it can use to offset SO 2 emissions at its other plants, keep for future plant expansions, or sell to other utilities or private parties.
How might the earth’s climate change in the future? Section 15-4
Estimated global average temperatures and average temperature change
Human activities emit large quantities of greenhouse gases A natural process called the greenhouse effect occurs when some of the solar energy absorbed by the earth radiates into the atmosphere as infrared radiation (heat). Four greenhouse gases absorb the heat which warms the lower atmosphere and the earth’s surface, helping to create a livable climate. –Water vapor (H 2 O). –Carbon dioxide (CO 2 ). –Methane (CH 4 ). –Nitrous oxide (N 2 O).
Comparing atmospheric concentrations of carbon dioxide (CO2) and the atmosphere’s average temperature, 1880–2009
Much of Alaska’s Muir Glacier in Glacier Bay National Park melted between 1948 and 2004
Satellite data shows a 39% drop in the average cover of summer arctic sea ice between 1979 and 2010
How CO2 emissions from the burning of fossil fuels in selected countries increased between 1965 and 2009
WHAT ARE SOME POSSIBLE EFFECTS OF A WARMER ATMOSPHERE? Section 15-5
Enhanced atmospheric warming could have severe consequences A 2003 U.S. National Academy of Sciences report laid out a nightmarish worst-case scenario in which human activities trigger new and abrupt climate and ecological changes that could last for thousands of years. –Ecosystems collapsing. –Floods in low-lying coastal cities. –Forests consumed in vast wildfires. –Grasslands, dried out from prolonged drought, turning into dust bowls. –Rivers and supplies of drinking and irrigation water could dry up.
Enhanced atmospheric warming could have severe consequences –Premature extinction of up to half of the world’s species. –Prolonged droughts. –More intense and longer-lasting heat waves. –More destructive storms and flooding. –Much colder weather in some parts of the world. –Rapid spread of some infectious tropical diseases.
If the average sea level rises by 1 meter (3.3 feet), the areas shown in red in Florida will be flooded
The orange-colored trees are those that are dead or dying—killed by mountain pine beetles
Areas in blue show counties in 28 U.S. states where one or both species of mosquitoes that transmit dengue fever have been found as of 2005
HOW HAVE WE DEPLETED OZONE IN THE STRATOSPHERE AND WHAT CAN WE DO ABOUT IT? Section 15-7
Our use of certain chemicals threatens the ozone layer A layer of ozone in the lower stratosphere keeps about 95% of the sun’s harmful ultraviolet (UV-A and UV-B) radiation from reaching the earth’s surface. Measurements show considerable seasonal depletion (thinning) of ozone concentrations in the stratosphere above Antarctica and the Arctic and a lower overall ozone thinning everywhere except over the tropics. Ozone depletion in the stratosphere poses a serious threat to humans, other animals, and some primary producers (mostly plants) that use sunlight to support the earth’s food webs.
A massive ozone thinning over Antarctica during several months in 2009
Our use of certain chemicals threatens the ozone layer Problem began with the discovery of the first chlorofluorocarbon (CFC) in 1930 and later Freon. –Popular non-toxic, inexpensive coolants in air conditioners and refrigerators, propellants in aerosol spray cans, cleaners for electronic parts such as computer chips, fumigants for granaries and ship cargo holds, and gases used to make insulation and packaging. –CFCs are persistent chemicals that destroy the ozone layer.
Why should we worry about ozone depletion? More biologically damaging UV-A and UV- B radiation will reach the earth’s surface. Causes problems with human health, crop yields, forest productivity, climate change, wildlife populations, air pollution, and degradation of outdoor materials.
Solid and Hazardous Waste Chapter 16
WHAT ARE SOLID WASTE AND HAZARDOUS WASTE, AND WHY ARE THEY PROBLEMS? Section 16-1
We throw away huge amounts of useful things and hazardous materials No waste in natural world because wastes of one organism become nutrients for others as a natural recycling of nutrients occurs. Modern humans produce huge amounts of waste that go unused and pollute. Solid waste—any unwanted or discarded material we produce that is not a liquid or a gas. –Industrial solid waste produced by mines, agriculture, and industries that supply people with goods and services. –Municipal solid waste (MSW), consisting of the combined solid waste produced by homes and workplaces.
Harmful chemicals are found in many homes
We throw away huge amounts of useful things and hazardous materials Classes of hazardous wastes are: –Organic compounds Various solvents, pesticides, PCBs, and dioxins. –Nondegradable toxic heavy metals Lead, mercury, and arsenic. –Highly radioactive waste produced by nuclear power plants and nuclear weapons facilities.
HOW SHOULD WE DEAL WITH SOLID WASTE? Section 16-2
We can burn or bury solid waste or produce less of it Waste management in which we attempt to manage wastes in ways that reduce their environmental harm without seriously trying to reduce the amount of waste produced. Waste reduction (produce much less waste and pollution), and the wastes we do produce are considered to be potential resources that can be reused, recycled, or composted. Integrated waste management—a variety of strategies for both waste reduction and waste management.
Integrated waste management
Put in Perpetual Storage Landfill Underground injection wells Surface impoundments Underground salt formations Stepped Art Convert to Less Hazardous or Nonhazardous Substances Natural decomposition Incineration Thermal treatment Chemical, physical, and biological treatment Dilution in air or water Produce Less Hazardous Waste Change industrial processes to reduce or eliminate hazardous waste production Recycle and reuse hazardous waste Fig , p. 422
Three big ideas The order of priorities for dealing with solid waste should be to produce less of it, reuse, and recycle as much of it as possible and safely burn or bury what is left. The order of priority for dealing with hazardous waste should be to produce less of it, reuse or recycle it, convert it to less-hazardous material, and safely store what is left. We need to view solid wastes as wasted resources and hazardous wastes as materials that we should not be producing in the first place.