14.4 The Air We Breathe

Name some sources of air pollution.

Air pollution The contamination of atmosphere by the introduction of pollutants from human and natural sources. The contamination of atmosphere by the introduction of pollutants from human and natural sources.

Primary Pollutants Pollutants that are put directly into the air by human or natural activity. Natural sources: dust, sea salt, volcanic gases and ash, pollen Other examples: vehicle exhaust

Smog Forms when the ozone and vehicle exhaust react with sunlight. Forms when the ozone and vehicle exhaust react with sunlight.

Secondary Pollutants Pollutants that form when primary pollutants react with other primary pollutants or with naturally occuring substances, such as water vapor. Pollutants that form when primary pollutants react with other primary pollutants or with naturally occuring substances, such as water vapor. Example: ozone, smog Example: ozone, smog

Smog

How does the burning of gasoline by cars contribute to air pollution? The burning of gasoline releases exhaust, which reacts with sunlight to form ozone and smog.

Industrial Air Pollution Industrial plants burn fossil fuels, coal, to produce energy which can cause large amounts of air pollutants. Industrial plants burn fossil fuels, coal, to produce energy which can cause large amounts of air pollutants. Other plants pollute the air with chemicals (oil refineries, chemical manufacturing plants) Other plants pollute the air with chemicals (oil refineries, chemical manufacturing plants)

How does burning of fuels to produce energy affect air quality? The burning of fossil fuels releases smoke and other pollutants.

Indoor Air Pollution Ventilation and limit the use of chemical cleaners can lower indoor air pollution. Ventilation and limit the use of chemical cleaners can lower indoor air pollution.

Acid Precipitation Precipitation such as rain, sleet, or snow that contains acids from air pollution. Precipitation such as rain, sleet, or snow that contains acids from air pollution.

Acid Rain

What causes acid precipitation? When pollutants that are released when fossil fuels are burned combine with water in the atmosphere, acid rain forms.

Acid precipitation and Plants Acidification – the process where acid precipitation can cause the acidity of soil to increase. ( some nutrients dissolves) Acidification – the process where acid precipitation can cause the acidity of soil to increase. ( some nutrients dissolves)

Acid Precipitation and Aquatic Ecosystems Acid shock Acid shock –a rapid change in a body of water’s acidity –can cause fish to die –Some communities spray powdered lime on acidified lakes to reduce the effects of acid precipitation.

What effects can the burning of fossil fuels have on aquatic ecosystems? The burning of fossil fuels can cause acid precipitation. When acid precipitation falls on lakes or streams, it may cause a rapid change in the acidity of the lake or stream. This process, called acid shock, can kill or damage large numbers of organisms.

The Ozone Hole The ozone layer is thinning The ozone layer is thinning Chemicals called CFCs are causing the ozone to break down into oxygen which doesn’t block the sun’s harmful rays. Chemicals called CFCs are causing the ozone to break down into oxygen which doesn’t block the sun’s harmful rays.

The Ozone Hole

Clean Air Act A law that allows the Environmental Protection Agency the authority to control the amount of air pollutants that can be released from any source. A law that allows the Environmental Protection Agency the authority to control the amount of air pollutants that can be released from any source. Scrubber – a device that is used to remove some pollutants before they are released by smokestacks Scrubber – a device that is used to remove some pollutants before they are released by smokestacks

Allowance Trading System EPA establishes allowances for the amount of a pollutant that companies can release. EPA establishes allowances for the amount of a pollutant that companies can release. Companies can sell some of their allowances or buy more. Companies can sell some of their allowances or buy more.

Controlling Pollution

Review Questions 1. How does smog form? * Vehicle exhaust reacts with sunlight and ozone to create smog. 2. What is the difference between primary and secondary pollutants? * Primary pollutants are pollutants that are put into the air directly by human or natural activity. Secondary pollutants form when primary pollutants react with other substances.

3. How are fossil fuels related to air pollution and acid precipitation? * When fossil fuels are burned, they release pollutants such as sulfur dioxide and nitrogen oxide. These chemicals react with water in the atmosphere to cause acid precipitation. They can also react with sunlight and ozone to form smog. 4.Is all air pollution caused by humans? Explain your answer. * No, some air pollutants, such as volcanic ash and gases, pet dander, and plant pollen, come from natural sources.