Transcript Atmosphere
Chapter 15 The Atmosphere You breathe out of which layer? The air we breathe and all the weather we see is contained in the lowest 1% of the Earth’s atmosphere. Take a deep breath What is air made out of? Is air strong? Is it matter? Why is our atmosphere important? Why doesn’t it float away Chapter 15 Big Idea Our atmosphere is critical to all life on Earth. Human actions have a great impact on our atmosphere. Section: Earth’s Atmosphere Describe the properties of the atmosphere. Identify the main layers of the atmosphere. Explain how heat is transferred in the atmosphere What is the Atmosphere? The atmosphere is a thin layer of gases surrounding our planet Why is the ATMOSPHERE important? Earth’s atmosphere makes life on Earth possible. 1. Protects us from sun’s rays. 2. Provides vital gases like oxygen, nitrogen and carbon dioxide. 3. Keeps temperature comfortable 4. Allows water to circulate around planet. 5. Protects us from meteoroids. The Air Around You Weather Weather is the state of the atmosphere at any one moment. What is it made of? Earth’s Atmosphere is made of: 1. 78 % Nitrogen 2. 21% Oxygen 3. 1% a bunch of others (Argon, Carbon Dioxide, Water Vapor…) Water in the Air Relative Humidity Amount of water vapor in the air Changes constantly Warm Air = More Moisture Condensation = Clouds Air Pressure The force of a column of air pushing down on an area Where is air pressure greater, sea level or top of a mountain? As altitude increases air pressure decreases…quickly Barometers An instrument used to measure air pressure. Changing air pressure is a great indicator of weather changes. Air pressure Differences in air pressure is going to help us understand: 1. Wind 2. Cloud formation 3. Tornadoes 4. Almost all weather Four Main Layers of Atmosphere The four main layers of our atmosphere are classified according to changes in temperature. Troposphere Stratosphere Mesosphere Thermosphere The Troposphere The Troposphere: Inner most layer (0 to 12km) Where all weather occurs The temperature decreases to -60 degrees at top. The Troposphere Clouds, rain, snow and all precipitation occur here. Air Pressure and Temperature drop quickly in troposphere. Stratosphere Layer above troposphere where atmosphere warms slightly Ozone layer located there blocks out harmful UV Rays Mesosphere “Middle Layer” Temperatures reach 90 degrees Celsius Where meteoroids burn up in atmosphere Thermosphere “Thermo” means heat Air is only 0.0001 % as dense as sea level Air slowly blends into outer space Hottest layer of atmosphere because energy from the sun strikes it first Heat Transfer in the Troposphere 1) Radiation: The transfer of energy through space, such as heat from the sun to Earth’s atmosphere Heat Transfer in the Troposphere 2) Conduction: The transfer of heat directly between two objects that are in contact Heat Transfer in the Troposphere 3) Convection: The transfer of heat by the movement of currents within a fluid (liquid or gas) Air Masses And Fronts The Air Outside Today, Was Somewhere Else Yesterday What IS An Air Mass? An Air Mass is a huge body of air with similar temperature, humidity and pressure. They sometimes spread over hundreds of square miles. Types of Air Masses There are 4 main types of air masses: 1) Polar 2) Tropical 3) Maritime 4) Continental Each has unique weather associated with it. 4 Major Air Masses of North America 1. 2. 3. 4. Maritime Tropical: Warm, Moist Air Maritime Polar: Cold, Moist Air Continental Tropical: Warm, Dry Air Continental Polar: Cold, Dry Air Where do they originate? What Are Fronts? Fronts are areas where 2 or more air masses collide. Air with different temperature, humidity and pressure DO NOT MIX WELL. Types of Fronts There are four types of front: 1) Cold Front 2) Warm Front 3) Stationary Front 4) Occluded Front Cold Fronts Cold Fronts occur where cold air runs into slowly moving warm air. Cold air being more dense pushes warm air up. Warm moist rising air can cause clouds and storms. Cold Fronts Warm Fronts Warm Fronts occur where a warm air mass collides with a slower moving cold air mass. Because warm air is less dense, it rides above the cold air. Warm Fronts Warm Fronts move more slowly than cold fronts so weather changes occur more slowly. In winter they often bring snow. Warm Fronts Section: Pollution of The Atmosphere What are the main sources of air pollution? Describe how smog forms Explain what a temperature inversion is and how it can make are pollution worse. TERMS: primary and secondary air pollution, catalytic converter, ZEVs, smog, temperature inversion What Causes Air Pollution? Air pollution is harmful substances in the air To plants, animals and other organisms Impact ecosystem functions WHAT SHOULD BE IN THE AIR? Some Natural Most Human Made Can you think of other human made AND natural sources of air pollution? Primary vs. Secondary Primary pollutant: put directly in the air (soot from smoke) Secondary forms when primary pollutant react with other pollutants (Smog) Primary vs. Secondary Primary vs. Secondary Sources of Air Pollution Main Sources of Air Pollution Burning fossil fuels in cars and at power plants (coal, oil and natural gas) Urban areas vehicles and industry Mobile vs. Stationary Sources What can you learn from this graph? Human Made vs. Natural History of Air Pollution Not a new problem Why do you think world air-quality today is a bigger problem? History of Air Pollution Not a “new” problem, but scale has changed during industrial revol. London “smog” killed 2,000 in 1880, 1,000 in 1911 and between 4,000 and 12,000 in 1952 1948 Donora PA 6,000 sick 1963 NYC 300 killed Today’s U.S. Air Quality http://airnow.gov/ U.S. Government Web Site With Up To Minute Air Quality Data From Monitors Across the country http://www.epa.gov/air/data/geosel.html U.S. EPA Air Quality Data: Tons of data regarding air quality across the U.S. http://www.epa.gov/airtrends/ EPA report on air trends in U.S. Smog (Smoky – Fog) Smog Secondary Pollutant in many urban areas Forms from chemical reaction Vehicle exhaust Needs sunlight and warm temperatures OZONE Smog Smog Levels Are Influenced By: Local climate Topography Population Density Amount of industry Transportation Huge Problem in cities …WHY? Smog: Why care? Smog Impacts: Breathing Problems Coughing, Eye Irritation Aggravates asthma, heart problems Speeds up aging of lung tissue Damage plants Reduce Visibility Smog and Temperature Inversion Normally as you go up in the troposphere what happens to temperature? Temperature Inversion occurs when a warmer layer forms above a cooler layer Traps air near ground Temperature Inversion Helena Montana Clean Air Act U.S. Law Passed Congress in 1963 and strengthened 1990 Has been huge success Since the Clean Air Act was first enacted in 1963, emissions of the worst pollutants in the U.S. have decreased by 57%. Clean Air Act Cars today are about 95% cleaner running Zero-Emission Vehicles (ZEV) Have no tailpipe emissions Chevy Volt 2010: will travel 30 miles on a battery before gas engine kicks in Nissan Leaf travels about 100 miles before needing to be charged again http://www.youtube.com/ watch?v=f48x9baSuF0 Clean Air Act Requires industries to clean up smokestack emissions Requires Scrubbers Scrubbers Section Review What are the main sources of air pollution? Describe how smog forms Explain what a temperature inversion is and how it can make are pollution worse. TERMS: primary and secondary air pollution, catalytic converter, ZEVs, smog, temperature inversion What will be the future?