u5 l4 human impact on the atmosphere

Unit 5 Lesson 4 Human Impact on the Atmosphere

Copyright © Houghton Mifflin Harcourt Publishing Company


Indiana Standards


• 8.2.6 Identify, explain, and discuss some effects human activities have on the biosphere, such as air, soil, light, noise and water pollution.

• 8.2.8 Explain that human activities, beginning with the earliest herding and agricultural activities, have drastically changed the environment and have affected the capacity of the environment to support native species. Explain current efforts to reduce and eliminate these impacts and encourage sustainability.

Air: What Is It Good For?


Why is the atmosphere important?

• Air is an important natural resource.

• The air you breathe forms part of Earth’s atmosphere.

• The atmosphere is a mixture of gases that surrounds Earth.



• The atmosphere provides gases that organisms need to survive, including oxygen and carbon dioxide.

• The atmosphere absorbs harmful high-energy radiation coming from space.




• The atmosphere keeps Earth warm.

• Without the atmosphere, temperatures on Earth would not be stable.

• The greenhouse effect is the way by which certain gases in the atmosphere absorb and reradiate thermal energy.



What is air pollution?

• The contamination of the atmosphere by pollutants from human and natural sources is called air pollution.

• Air pollution can come from natural sources, such as volcanic eruptions, wildfires, and dust storms.

• In cities and suburbs, most air pollution comes from the burning of fossil fuels.



What is air pollution?

• Air pollution can be classified as gases such as carbon monoxide, sulfur dioxide, and ground-level ozone.

• Air pollution can also be classified as particulates. Particulates consist of tiny particles of solids that are suspended in air or water.

• The particulates from vehicle exhaust are a major cause of pollution in cities.



It Stinks!


What pollutants can form from vehicle exhaust?• Vehicle exhaust is a common source of air

pollution in urban areas.

• Ground-level ozone is produced when sunlight reacts with vehicle exhaust and oxygen in the air.

• Although ozone in the ozone layer is necessary for life, ground-level ozone is harmful.


What pollutants can form from vehicle exhaust?• Vehicle exhaust also produces smog.

• Smog is a brownish haze that forms when ground-level ozone and vehicle exhaust react in the presence of sunlight.



What pollutants can form from vehicle exhaust?• Smog can damage the lungs and irritate the eyes

and nose.



How does pollution from human activities produce acid precipitation?• Precipitation such as rain, sleet, or snow that

contains acids from air pollution is called acid precipitation.

• Burning fossil fuels releases sulfur dioxide and nitrogen oxides into the air.

• When these gases mix with water in the atmosphere, they form sulfuric acid and nitric acid.



How does pollution from human activities produce acid precipitation?• Sulfuric acid and nitric acid are strong acids. They

can make precipitation so acidic that it is harmful to the environment.



What are some effects of acid precipitation?• Acid precipitation can cause soil and water to

become more acidic than normal.

• Changes in soil acidity cause soil to lose some of the nutrients that plants need.



What are some effects of acid precipitation?• Acid precipitation can also make lakes and

streams more acidic and cause soils to release toxic metals into the water.

• This can harm aquatic organisms.



How’s the Air?


What are measures of air quality?

• Air quality is the measure of how clean or polluted the air is.

• As pollution increases, air quality decreases.

• Two major threats to air quality are vehicle exhausts and industrial pollutants.



• The Air Quality Index (AQI) is a number used to describe the air quality of a location.

• The higher the AQI number, the more people are likely to have health problems linked to air pollution.

• The air inside a building can become more polluted than the air outside.




• What are some sources of indoor air pollution?



How can air quality affect health?

• Daily exposure to small amounts of air pollution can cause serious health problems.

• Certain people, such as children, elderly people, and people with health problems, are especially vulnerable to the effects air pollution.

• Short-term effects include coughing, headaches, and wheezing. Long-term effects include lung cancer and emphysema.



Things are changing


How might humans be changing Earth’s climates?• As a result of burning fossil fuels, the atmosphere

today contains about 37 percent more carbon dioxide than it did in the mid-1700s.

• Average global temperatures have also risen in recent decades.


How might humans be changing Earth’s climate?• It is hard to know exactly how much the extra

greenhouse gases change the temperatures.

• Computer models designed to understand climate change predict that average global temperatures will continue rising.



What are some predicted effects of climate change?• Many changes on Earth have already been linked

to higher temperatures.

• Changes in rainfall patterns and rising sea levels will have many negative effects on life on Earth.

• Such changes will likely have political and economic effects on the world.



How is the ozone layer affected by air pollution?• Earth’s protective ozone layer is thinning over the

polar regions, allowing more harmful ultraviolet radiation to reach Earth’s surface.

• Chemicals called chlorofluorocarbons (CFCs) cause ozone to break down. CFCs once had many industrial uses, but now they are banned.

• However, CFCs released in the atmosphere decades ago will stay there many more decades, breaking down more ozone.



u5 l4 human impact on the atmosphere

Science

human impact

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water pollution

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pollution increases

atmosphere important

acid precipitation