When Air Turns Bad

Why it matters

The air is invisible, yet we fill it with smoke, soot and fumes every day. Some of our choices poison it — and some can help clean it right back up.

Predict first

Which of these makes the air DIRTIER?

Smoke and fumes from factories and vehicles add harmful gases and soot to the air — that is air pollution. Trees, solar power and clean fuels help protect the air instead.

• Planting more trees along the road
• Thick black smoke from a factory chimney — correct
• Using solar panels for electricity
• Switching a bus to run on cleaner CNG

What you do

Sort each thing into the correct bin: does it pollute the air, or does it clean and protect the air?

Check yourself

What causes acid rain?

Waste gases such as sulphur dioxide dissolve in rain drops to form acids, giving acid rain that harms plants, buildings and lakes.

Too much carbon dioxide (CO₂) in the air causes which problem?

Carbon dioxide is a greenhouse gas. It traps the Sun's heat near the Earth, so extra CO₂ makes the planet warmer — global warming.

What do CFC gases do to the atmosphere?

CFCs break down the ozone layer high in the atmosphere. That layer shields us from the Sun's harmful ultraviolet (UV) rays, so damaging it is dangerous.

• Gases like sulphur dioxide (SO₂) dissolving in rain water — correct
• Too much oxygen in the air
• Rain falling through clean forests
• Water from the sea evaporating
• Global warming through the greenhouse effect — correct
• The Earth getting colder and colder
• Rivers turning into stone
• The Sun going out
• They damage the ozone layer that blocks harmful UV rays — correct
• They make the ozone layer thicker and stronger
• They turn the sky green
• They have no effect on the air