4Troposphere atmosphere’s inner layer contains most of Earth’s air N2 ( 78% ), O2 ( 21% ), CO2 ( 0.04% )weather occurs heretemperature drops with an increase in altitude
5Stratosphere layer above troposphere temperature rises with altitude our global sunscreen
6Stratosphere cont’d contains O3 “good ozone” ozone layer prevents 99% of harmful ultraviolet radiation from reaching Earth’s surface
7Ozone in the Troposphere (Pollutant) Trace amounts of O3 that form in the troposphere as a component of urban smog cause damage to:• plants• materials, e.g., rubber• respiratory systems of humans & other animals
8What is Air Pollution?one or more chemicals in high enough concentrations in the air to:1) harm organisms or materials2) alter climatethese chemicals are called air pollutants.
9Sources of Air Pollution Natural events(e.g., volcanic eruptions, dust storms)2. Human activities(e.g., emissions from cars and smoke stacks)
10Major Air Pollutants Carbon Dioxide ( CO2) linked to global warming 2. Sulfur Dioxide (SO2)Linked to global warming, acid deposition3. Nitrogen OxidesLinked to global warming
11Major Classes of Air Pollutants cont’d 4. Volatile Organic Compounds- e.g., methane, propane, benzene, chlorofluorocarbons (CFCs)found in paints and protective coatingshave long-term health risks including:compromised immune system in infantsrespiratory disorders
12Major Classes of Air Pollutants cont’d 5. Suspended Particles- e.g., solid particles (dust, asbestos, soot)- e.g., liquid droplets (pesticides, sulfuric acid)- linked to respiratory disorders
13Types of Air Pollutants Primary Pollutant- chemical, that occurs in a harmful concentration, added directly to the air by natural events or human activitiese.g. sulphur dioxide, carbon monoxide, carbon dioxide
14Types of Air Pollutants cont’d Secondary Pollutant- harmful chemical formed in atmosphere when a primary air pollutant reacts with the normal air components or with other air pollutantse.g. ozone, sulphur trioxide
15Urban Air Pollution Smog - originally a combination of smoke & fog - now describes other mixtures in the atmosphere
16Urban Air Pollution cont’d Industrial Smog- consists mainly of a mixture of sulfur dioxide, suspended droplets of sulfuric acid and a variety of suspended solid particles- found in cities that burn large amounts of coal and heavy oil which contain sulfur impurities
18Effects of Climate & Topography on Air Pollution Areas with high average annual precipitation, help cleanse the air of pollutants.Winds help sweep pollutants away and bring in fresh air.Hills & mountains reduce the flow of air in valleys below and allow pollutant levels to build up at ground level.
19Effects of Climate & Topography on Air Pollution cont’d Buildings in cities slow wind speed & reduce dilution and removal of pollutants.The process of hot air rising and cold air sinking causing continual mixing of air, helps keep pollutants from reaching dangerous levels near the ground.
20Temperature Inversion also called thermal inversiona layer of warm air settles over a layer of cooler air that lies near the ground.the warm air holds down the cool air and prevents pollutants from rising and scattering allowing them to build up to harmful levels
22Smoke rising in Lochcarron, Scotland is stopped by an overlying layer of warmer air – thermal inversion
23Acid Depositionthe falling of acids and acid-forming compounds from the atmosphere to the earth’s surfacecommonly known as acid rain
24Acid Rainrefers only to wet deposition of droplets of acids and acid-forming compoundsnatural precipitation is slightly acidic (pH )acid rain can have a pH of 4.3 or 3 (as acidic as vinegar)
25Harmful Effects of Acid Deposition contributes to human respiratory diseasesdamages foliage and weaken treescontaminate fishdamages statues, buildings, metals, & car finishesreleases aluminium ions which damage tree roots
26Greenhouse Effect natural effect that traps heat in the troposphere some of the heat flowing back toward space from Earth’s surface is absorbed, by H2O vapour, CO2, O3 and other gases, then radiated back toward Earth’s surface
28Greenhouse Gasesgases in the troposphere that cause the greenhouse effectinclude:carbon dioxidechlorofluorocarbons (CFCs)ozonemethanewater vapournitrous oxide
29Greenhouse Gases cont‘d the 2 predominant greenhouse gases are:water vapourcarbon dioxideif the atmospheric concentrations of these gases increase, the average temperature of the troposphere will gradually rise
30Global Warmingwarming of atmosphere due to increases in the concentrations of one or more greenhouse gases primarily as a result of human activities, mainly:burning of fossil fuelsuse of CFCsagriculturedeforestation
31Global Warming cont’dIn recent decades certain greenhouse gases have increased in concentration:carbon dioxidemethanenitrous oxideCFCsCO2 contributes to ~ 55% of global warming.
33Possible Impacts of Global Warming on Caribbean States disastrous for ecosystems e.g. coral reefs (coral bleaching)alter climatic conditions faster than some species could adaptshift food-growing areasrise in sea levels due to melting of icecaps and glaciers may flood coastal settlements
34Meltwater from Ice Sheet in Greenland flowing into ocean
35Possible Impacts of Global Warming on Caribbean States cont’d more frequent and fierce hurricanesdisastrous for economic and social systems
36Ozone Layerlayer of gaseous ozone that protects life on Earth by filtering out harmful ultraviolet radiation from the sunbeing depleted by CFCs, halons and other chemicals
37CFCs Chlorofluorocarbons used in air conditioners, refrigerators, aerosol spray cans, cleaners for electronic parts, hospital sterilants, fumigants, plastic foamozone eaters
38Impact of Ozone Depletion increased cases of cancer & cataractssuppression of human immune systemlowers crop yielddegradation of materialsreduction in phytoplankton
39Noise Pollution- any unwanted, disturbing or harmful sound that impairs or interferes with hearing, causes stress, hampers concentration and work efficiency or causes accidents
41Solutions to Air & Noise Pollution enforce air & noise pollution lawsuse emission control devicesban or limit smoking to well-ventilated areastax each unit of pollution produceduse office machines in well-ventilated areasshift to less polluting energy sourcesincrease intake of outdoor aircar exhaust inspections