10 min readConcept sheetSection A MCQ (1 mark) and objective (2 marks, fill in the blanks); Section B very short answer (2 marks) or short answer (3 marks)

Pollution of air, soil and noise

Pollution is any undesirable change in air, water or land that harms living things and buildings. Smoke, soot, plastics and unwanted sound (noise) are everyday pollutants.

PollutionAn undesirable change in the physical, chemical or biological features of air, water or land that harms people, wildlife and buildings or monuments

Four typesAir, water, soil (land) and noise pollution

NoiseUnwanted sound; loudness is measured in decibels (dB)

Particulate pollutantsFine solid particles in air, such as dust, soot, cement and fibres; they block leaf stomata and harm the lungs

What pollution means

Almost every activity releases some unwanted substance. Soaps and detergents from washing change the quality of water. Cooking on firewood gives out smoke. Farms add fertilisers and pesticides, which help crops but pollute when overused. When unwanted substances build up to a level that harms living things, we call it pollution. In full, pollution is an undesirable change in the physical, chemical or biological features of air, water or land. It can harm people, wildlife and cultural assets such as buildings and monuments.

Air pollution: sources and control

Every activity, from cooking at home to running factories, adds to air pollution.
Vehicle exhaust gives out gases such as carbon monoxide and oxides of nitrogen, and soot from diesel engines.
Burning fuels raises the level of carbon dioxide, which adds to global warming.
Suspended particulate matter, such as dust and soot, stays in the air and causes allergies, asthma and bronchitis.
Control: fit filters and dust-catching devices in factory chimneys, use cleaner fuels such as CNG, and keep vehicles well serviced.

Activity: compare particulate pollution on leaves (practical)

1
Collect leaves of the same kind from different places: a quiet residential area, a park, a busy road crossing and a construction site.
2
Spread an old white cotton cloth on a flat surface.
3
Place each leaf face down on the cloth and press it gently with an outward stroke of your fingers.
4
Compare the imprints and record the place and the shade of each imprint in a table.
5★
Conclusion: leaves from busy, polluted areas leave the darkest marks, because more soot from vehicle exhaust settles on them.

★ key step

Soil (land) pollution

Soil pollution is the addition of substances that make soil less fertile and unable to support life.
From homes: plastic bags, glass bottles, kitchen scraps and other solid waste.
From industry: leftover chemicals, fly ash (left after burning coal) and metal scrap.
Agricultural sources: too much fertiliser and pesticide.
Soil erosion, from uprooting plants and overgrazing, also degrades the land.

Noise pollution at a glance

Aspect	Details
What it is	Unwanted sound; usually higher in cities and industrial areas than in villages
Sources	Industries; aircraft, trains and road vehicles; loudspeakers and loud music in public places; noisy firecrackers; a loud television
Effects on health	Earache, temporary or permanent hearing loss, ringing in the ears, headache, irritability, poor concentration, high blood pressure, irregular heartbeat, disturbed sleep and slow recovery from illness
Control	Keep radio and TV low; use the horn only in emergencies; avoid noisy crackers; service machines and fit silencers; plant a green belt of trees, which absorbs sound; report loudspeakers at odd hours to the police

Activity: a noise survey near a busy road

1
Pick two noisy sites, such as a busy road, a railway crossing or a construction site.
2
Talk to at least two people who live at each site.
3
Ask whether they have stress, headaches, trouble concentrating or reduced hearing, and record their answers in a table.
4
Compare the two sites and note which effects are most common.
5★
Suggest two ways to cut noise without moving house. Examples: a row of trees in front of the house, and keeping your own TV and music low.

★ key step

In real life

Traffic police at busy crossings breathe soot and hear loud horns for hours, so many wear masks. 'No honking' signs near hospitals are a direct step against noise pollution.

Exam angle

1 marks: “In which unit is the loudness of sound measured?” The decibel (dB).

2 marks: “Give two sources of soil pollution from a home and one way to reduce each.” Plastic bags: use a cloth bag. Kitchen waste: compost it. (Glass bottles: reuse or recycle them.)

3 marks: “A family lives beside a busy highway where heavy trucks pass all night. Describe three ways the noise may affect their health, and three steps they can take to cut it.” Effects: hearing loss or ringing in the ears; headache, irritability and poor concentration; high blood pressure and disturbed sleep. Steps: plant a green belt of trees in front of the house; keep the windows facing the road shut at night; ask the local authorities to enforce silencers and 'no horn' signs near homes.

Remember it

Air, Water, Soil, Sound: four kinds of pollution. Noise is measured in decibels, and trees are nature's sound-absorbers.