3 Air pollution

p.268

Objectives

• Students should learn:• that air can be polluted with smoke and gases,

such as sulfur dioxide, which contributes to acid rain

• that acid rain may damage trees• that plants and animals cannot survive if the

water in rivers and lakes becomes too acidic• that tiny solid particles polluting the air can

cause global dimming

Outcomes

• Most students should be able to:• describe how acid rain is formed• describe some of the effects of acid rain on

living organisms• explain how air pollution can result in global

dimming.• Some students should also be able to:• analyse and interpret scientific data concerning

the effects of acid rain.

Specification

• Waste may pollute:• – … air, with smoke and gases such as sulfur

dioxide, which contributes to acid rain.• Analyse and interpret scientific data

concerning environmental issues.

Biology B3 4.3 Air pollution

Answers to in-text questions

a Oil, coal, natural gas. b Sulfur dioxide and nitrogen oxides. c The acid kills the leaves, so the trees cannot make food. If it soaks into the soil, it can kill the roots.

Summary answers

 1 fossil, carbon dioxide, sulfur, nitrogen oxides, sulfuric, nitric, acid rain 2 a i Sulfur dioxide, carbon dioxide and nitrogen oxides are produced from impurities when fossil fuels are burned. These cause air pollution. ii Sulfur dioxide and nitrogen oxides in the air dissolve in the rain and fall to the ground. The water runs into streams, rivers, etc. and lowers the pH, making them more acidic. iii Acid rain falls on the ground, soaks in and causes it to be acidic.

b The sulfur dioxide and nitrogen oxides produced by burning fossil fuels are carried high in the air by the prevailing winds. They can be blown hundreds of miles before they dissolve in rain and are carried to the ground. So every country needs to control emissions from the burning of fossil fuels to prevent any country being affected by acid rain. 3 a Global dimming is the reduction in light reaching the surface of the Earth because light is refl ected away by the build up of pollution particles in the air (from sulphur compounds and smoke particles).

b 14 x 100 = 78% 18

c Europe has controlled air pollution as seen by reduction in sulfur emissions; smoke will be controlled at the same time; this reduces the number of particles in the air reflecting the light and so reverses dimming effect of air pollution.

Compulsory slides you must complete and use;

Global dimming

• What is it and what effect does it have?

What causes acid rain?

• Give detail on smoke, gases and sulfur dioxide

What damage does acid rain cause

• Trees• Animals and plants in rivers and lakes

The effects of acid rain on cress

Acid kills the leavesIt lands on

It soaks into the soilAnd kills roots too

‘fun’ activity

• Class card sort (see next slide)

Class card sort;

A

A

A

A

A A

B

B B C

D

D

Useful slides you may use;

• Look in the air quality files (presentation near end is good)

Air pollutionHuman activity produces two main types of air pollutant:

particulates – These are tiny particles suspended in air (e.g. smoke), which are usually produced by the combustion of fossil fuels.

noxious gases – These include carbon dioxide (CO2), sulfur dioxide (SO2) and nitrogen oxides (NOx).

Air pollution has been a major problem since the Industrial Revolution of the late 18th Century, and has been made worse by humans’ reliance on burning fossil fuels for energy.

Air pollution, global warming, acid rain, damage to the ozone layer and smog. Each of these has serious implications for the environment and human health.

Acid rain

Acid rain

Digital Vision 15(NT)

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Get the gas right

Holes in the ozone layer

Sulfur dioxide and nitrogen oxidesAcid rain

Carbon dioxideGlobal warming

GasPollution problem

CFCs

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Acid rain• Sulfur dioxide is released when

fossil fuels like coal and oil are burned.

• Acid rain damages rivers and lakes, making them more acid, so killing fish.

• Acid rain damages trees.• Acid rain damages limestone

buildings. • Nitrogen oxides released in car

and jet fumes also cause acid rain.

Digital Vision (NT)

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Formation of acid rain

Sulfurimpurities in coal and oil

Sulfurdioxide releasedwhenburnt

Dissolves in rainand clouds

Falls as acidrain, less thanpH5.5

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Formation of acid rain

Acid rain

• Sulfur dioxide is released when fossil fuels like coal and oil are burned.

• It dissolves in rain water to make sulphuric acid

• Acid rain (pH less than 5.5) damages rivers and lakes, making them more acid, so killing fish.

• Acid rain damages trees.• Acid rain damages limestone

buildings. • Nitrogen oxides released in car

and jet fumes also cause acid rain.

Digital Vision (NT)

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Preventing acid rain

• International agreements to reduce sulfur dioxide pollution.

• Energy efficiency means less coal burned to make electricity.

• Ultra low sulfur petrol.• Alternative energy sources like natural gas, solar,

wind farms and nuclear.

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The effect of international agreements