Presentation on theme: "Air Pollution and Stratospheric Ozone Depletion"— Presentation transcript:
1Air Pollution and Stratospheric Ozone Depletion Chapter 15Air Pollution and Stratospheric Ozone Depletion
2Air PollutionAir pollution- the introduction of chemicals, particulate matter, or microorganisms into the atmosphere at concentrations high enough to harm plants, animals, and materials such as buildings, or to alter ecosystems.
6Primary PollutantsPrimary pollutants- polluting compounds that come directly out of the smoke-stack, exhaust pipe, or natural emission source.Examples: CO, CO2, SO2, NOx, and most suspended particulate matter.
7Secondary PollutantsSecondary pollutants- pollutants that have undergone transformation in the presence of sunlight, water, oxygen, or other compounds.Examples: ozone, sulfate and nitrate
8Natural Sources of Air Pollution VolcanoesLightningForest firesPlants
9Global Air Pollution 44% of the Nox emissions are natural 30% of the SO2 emissions are natural44% of the Nox emissions are natural89% of the VOC emissions are natural!Anthropogenic emissions are more than double the natural emission levels.
10Anthropogenic Sources of Air Pollution On-road vehiclesPower plantsIndustrial processesWaste disposal
12AP Quiz Name the 9 major air pollutants (9pts) What is the difference between primary and secondary pollutants? (2pts)Name the four natural sources of air pollution AND one of the pollutants fpr each (8pts)What are the 4 major anthropogenic sources of air pollutants? (4pts)What are the 4 major anthropogenic air pollutants AND what is the primary source of each? (8pts)
14Thermal InversionsThermal Inversion- when a relatively warm layer of air at mid-altitude covers a layer of cold, dense air below.The warm inversion layer traps emissions that then accumulate beneath it.
17Acid DepositionAcid deposition- occurs when nitrogen oxides and sulfur oxides are released into the atmosphere and combine with atmospheric oxygen and water. These form the secondary pollutants nitric acid and sulfuric acid.These secondary pollutants further break down into nitrate and sulfate which cause the acid in acid deposition.
18Effects of Acid Deposition Lowering the pH of lake waterDecreasing species diversity of aquatic organismsMobilizing metals that are found in soils and releasing these into surface watersDamaging statues, monuments, and buildingsEffects of Acid Deposition
19Ways to Prevent Air Pollution Removing sulfur dioxide from coal by fluidized bed combustionCatalytic converters on carsScrubbers on smoke stacksBaghouse filtersElectrostatic precipitators
20Fluidized bed combustion When granulated coal is burned with Limestone (CaCO3)Fluidized bed combustion
21Uses a catalyst to neutralize exhaust and remove pollutants Catalytic Converter
25Stratospheric OzoneThe stratospheric ozone layer exists roughly kilometers above the Earth.Ozone has the ability to absorb ultraviolet radiation and protect life on Earth.
26Formation and Breakdown of Ozone First, UV-C radiation breaks the bonds holding together the oxygen molecule )2, leaving two free oxygen atoms: O2 + UV-C -> 2OSometimes the free oxygen atoms result in ozone: O2 + O -> O3Ozone is broken down into O2 and free oxygen atoms when it absorbs both UV-C and UV-B ultraviolet light: O3 + UV-B or UV-C -> O2 + O(Note: UV-A, UV-B and UV-C refer to the type of wave energy)long med short wave radiation
27Anthropogenic Contributions to Ozone Destruction Certain chemicals can break down ozone, particularly chlorine.The major source of chlorine in the stratosphere is a compound known as chlorofluorocarbons (CFCs)CFCs are used in refrigeration and air conditioning, as propellants in aerosol cans and as “blowing agents” to inject air into foam products like Styrofoam.
28Anthropogenic Contributions to Ozone Destruction When CFCs are released into the troposphere they make their way to the stratosphere.The ultraviolet radiation present has enough energy to break the bond connecting chlorine to the CFC molecule.which can then break apart the ozone molecules.
29Anthropogenic Contributions to Ozone Destruction First, chlorine breaks ozone’s bonds and pulls off one atom of oxygen, forming a chlorine monoxide molecule and O2: O3 + Cl -> ClO + O2Next, a free oxygen atoms pulls the oxygen atom from ClO, liberating the chlorine and creating one oxygen molecule: ClO + O -> Cl + O2One chlorine atom can catalyze the breakdown of as many as 100,000 ozone molecules before it leaves the stratosphere!!!!
30Depletion of the Ozone Layer Global Ozone concentrations had decreased by more than 10%.Depletion was greatest at the polesDecreased stratospheric ozone has increased the amount of UV-B radiation that reaches the surface of Earth.
31Indoor Air PollutantsWood, animal manure or coal used for cooking and heating in developing countries.AsbestosCarbon MonoxideRadonVOCs in home products
32Wood, Manure and Coal3 BILLION people use these as a means of heat or for cooking.Normally they do not have a vent or an exhaust system.Creates a build up of CO and particulate matter.Causes respiratory infections: pneumonia, bronchitis and cancerWHO estimates 1.6 million people die annually 56%-children 90% of deaths are in the developing world.
33Risks in the developed world People spend more time indoorsMore insulations does not allow air to circulate in and out of the home resulting in more contact with the residents.Highly processed products can release harmful chemical vapors
34Asbestos Fibrous mineral used as an insulator Miners are at the most risk.If left undisturbed it poses little to no threat to the env or human health.Causes Asbestosis & Mesothelioma (Lung cancer caused by breathing asbestos fibers)
35Carbon Monoxide- COComes from exhaust: incomplete combustion of fossil fuels (natural gas)Limits oxygen transport in the blood, depriving your body of oxygen will lead to unconsciousness and then death.
36Radon Radon-222 Radioactive gas- produced from the breakdown of U Seeps into homes through cracks in the foundation or in water pumped out of the ground.21,000 people die from lung cancer annually.