Do Now Read pg. 452-453 and in your notebook describe the composition of the atmosphere. Be ready to discuss

The Atmosphere 15 CHAPTER Placeholder opening page, but maybe we can duplicate the look of the SE chapter opener page by using the same fonts and colors (and maybe that Ch 14 icon?)

Properties of the Atmosphere Lesson 15.1 Earth’s Atmosphere Properties of the Atmosphere Atmosphere-thin layer of gases that surrounds Earth Composition: 78% nitrogen, 21% oxygen, and 1% other gases (water vapor) Temperature: Varies and location Pressure: air pressure (force exerted by air on area below it) decreases with altitude (Pile of books) Barometer

Relative Humidity -ratio of water vapor in air to the maximum amount the same air could contain at the same temperature (*Humidity is high sweat cannot evaporate) •affected by temperature and location; in general, warm air holds more water. •When air cools, water vapor may condense to liquid or to ice. Water vapor can only condense on surfaces, such as a petal or a dust particle. This is also how clouds form

Layers of Atmosphere Troposphere: 0–11 km; movement of air, weather Lesson 15.1 Earth’s Atmosphere Did You Know? The stratosphere and mesosphere are cold, but the upper thermosphere can be hotter than 1500°C. Layers of Atmosphere Troposphere: 0–11 km; movement of air, weather Stratosphere: 11–50 km; ozone layer, absorbs and scatters UV rays Mesosphere: 50–80 km; meteoroids burn up, Coldest layer Thermosphere: 80+ km; disturbances produce aurora borealis

Ozone Layer ozone concentrated in stratosphere. Reduces the amount Ultraviolet (UV) rays. *Can damage living tissue and cause harmful changes in DNA) protective layer Ozone in troposphere - pollutant & harms lung tissue & plant growth

Weather Vs. Climate Weather-atmospheric conditions over a short period of time (Day to Day) Ex: Partly cloudy 60 degrees. Climate- pattern of atmospheric conditions in a large geographic region over long periods of time (Temperate/Desert)

Heat Transfer in the Troposphere Lesson 15.1 Earth’s Atmosphere Heat Transfer in the Troposphere • Radiation: transfer of energy through space, such as heat from the sun to Earth’s atmosphere (handle of a door with sun beating on it) Dark(absorb) vs. lighter(reflect) objects • Conduction: The transfer of heat directly between two objects that are in contact-Between the earth and the earths surface (Touching door handle-Heat from handle to hand) • Convection: transfer of heat by the movement of currents within a fluid (liquid or gas)

Convection Currents Warm air is less dense than cool air. •When air near the surface heats up, it rises; as it rises, it cools and then sinks. •Rising and sinking fluids generate convection currents. •Cause wind and heat to move through the atmosphere

Air Masses and Fronts • Air masses: Large bodies of air with similar properties • Fronts: Boundaries between air masses of different properties Warm front Cold front • Boundary along which a mass of warmer, • Boundary along which a mass of cooler, moister air pushes against a mass of drier air pushes against a mass of cooler, drier air warmer, moister air • Can produce light precipitation • Can produce heavy precipitation

Quick Check 1.What is the main source of energy that influences weather and climate? 2.The air you breathe in mostly made of__________. 3.In what layer does weather occur? 4.T or F Warm air can hold less water vapor than cold air. 5.How does the ozone layer benefit living things on earth?

Pg. 453 Figure 1 1-Dry air is mainly composed of what gas? 2-Give two examples of other gases found in dry air. 3-Turn to pg. 460 and answer #1&4

Do Now: In notebook answer the questions from pg. 460 #2 & 3

Sources of Air Pollution Lesson 15.2 Biomes Sources of Air Pollution Natural processes: Windblown dust, particles in volcanic eruptions, smoke and soot from fire Human sources: Most come directly or indirectly from the burning of fossil fuels. Did You Know? Humans can increase the hazards of natural air pollution. For example, by removing trees, humans expose soil, which can dry out and add to huge dust storms when picked up by wind. Dust storm approaching a U.S. farm during the 1930s

Types of Air Pollutants Lesson 15.2 Pollution of the Atmosphere Types of Air Pollutants Primary air pollutants: Released directly into the atmosphere; example: soot Secondary air pollutants: Formed when primary pollutants react chemically with other substances; example: sulfuric acid Refer to Chart page 463 *In your notes copy two primary pollutants and copy into notes the secondary pollutants *

How Air Pollutants Affect Your Health Lesson 15.2 Pollution of the Atmosphere How Air Pollutants Affect Your Health Lung irritation &respiratory illnesses (asthma) Carbon monoxide- interferes with body’s ability to use oxygen. Trace amounts of some air pollutants (benzene/soot) may contribute to cancer.

Smog mix of air pollutants that forms over cities Lesson 15.2 Pollution of the Atmosphere Smog mix of air pollutants that forms over cities Industrial smog (soot, sulfur, and water vapor) comes from industrial sources. Photochemical smog -tropospheric ozone created when primary pollutants from vehicle exhaust react to sunlight.

Temperature Inversions Lesson 15.2 Pollution of the Atmosphere Temperature Inversions Did You Know? A thermal inversion caused London’s “killer smog.” Normally, air near Earth’s surface warms and rises, carrying pollutants with it. When a layer of warmer air sits over a layer of cooler air, it traps pollution near Earth’s surface.

Lesson 15.2 Pollution of the Atmosphere Acid Deposition Sulfur dioxide & nitrogen oxides react w/ water, oxygen, &other chemicals form acids. Acid falls as particles or dissolves in precipitation, lowering the pH of rain and snow. pH Scale- 0-14 0-6 Acidic 7-Neutral 8-14 basic Acid deposition harms forest and lakes and damages human structures. Pg. 468- Jot down some effects of acid deposition Did You Know? Rainwater is naturally acidic (pH 5.6), but acid precipitation in some parts of the U.S. has a pH as low as 4.

Quick Check 1.How does carbon monoxide affect human health? 2.Acid Rain would have a pH of what? 3.Chemicals releases into the air are called ___________

Answer the following questions Pg. 465 Reading check point Pg. 466 Reading checkpoint Figure 15 answer the question underneath

Lesson 15.3 Controlling Air Pollution The Clean Air Act First passed 1963 -to protect human & environmental health by improving air quality(revised) Limits emissions of pollutants, sets standards for air quality establishes a legal framework for suing industries that break the rules provides funding for pollution control

Major Accomplishments of the Clean Air Act Lesson 15.3 Controlling Air Pollution Major Accomplishments of the Clean Air Act Catalytic converters, present in all cars since 1975, reduced vehicle emissions. Lead -phased out of gasoline. Industries & power plants have reduced releases of pollutants by using: Scrubbers- remove or alter chemicals before they leave factory smokestacks. Did You Know? The removal of lead from gasoline has led to a 99% reduction in lead emissions since 1973.

The Ozone Hole Ozone-pollutant in troposphere Lesson 15.3 Controlling Air Pollution The Ozone Hole Ozone-pollutant in troposphere -stratosphere it creates a protective barrier against UV radiation. Chlorofluorocarbons- chemicals used to be found in everything from aerosol cans to refrigerators, destroyed ozone, causing an “ozone hole” to form over Antarctica. ozone hole- allows more UV radiation to reach Earth’s surface, potentially increasing cases of skin cancer. Aerosol spray can 25

Recovery of the Ozone Layer Lesson 15.3 Controlling Air Pollution Recovery of the Ozone Layer Montreal Protocol -international treaty signed in 1987 that has cut CFC production by 95% since the 1980s. Ozone levels in the stratosphere have begun to stabilize, and the ozone hole will likely start to disappear. Pg 471 REAL DATA Ozone Hole 1979 Ozone Hole 2000