Glossary

Absorb
Receive or take in.

Acid Rain
Water in the air mixes with pollution, which comes from cars, factories and power stations to make acids. These acids then fall to the ground with rain.

Acid
Any substance with a pH of less than 7.

Alkali
Any substance with a pH greater than 7.

Asthma
A disease that makes it difficult for a person to breathe, especially during exercise.

Atmosphere
The layer of gases that surrounds the Earth.

Carbon Monoxide
A highly poisonous gas produced when fuel is burnt. It is mainly emitted from car exhausts.

Catalytic Converter
A filter fitted to car exhausts to help remove pollution.

Decay
To slowly waste away.

Disperse
To scatter and distribute pollutants in the atmosphere.

Dry Deposition
The direct deposition of particles resulting from air pollution.

Emit
To release into the air.

Fossil Fuels
Sources of energy such as coal, oil and natural gas.

Fungi
Neither plants nor animals, these organisms include moulds, mildews, yeasts and mushrooms.

Gravity
The force of attraction that pulls things towards the Earth.

Hydrocarbons
Organic substances containing carbon and hydrogen.

Invertebrates
Any animals that do not have a skeleton or backbone.

Limestone
A type of rock used as a building material.

Marble
A hard rock that is formed when limestone is heated to very high temperatures within the Earth. It is also used as a building material.

Minerals
Substances formed naturally in rocks and earth.

Neutral
Neither acidic, nor alkaline, with a pH of 7.

Nitric Acid
A component of acid rain formed when nitrogen oxide pollution mixes with moisture in the air.

Nitrogen Oxides
Polluting gases produced when fuel is burnt.

Nutrients
Substances that are nourishing and help a plant or animal to grow.

Ozone
A pollutant that is formed when nitrogen oxides, carbon monoxide and hydrocarbons mix and react together in the presence of sunlight.

Particulates
Pollution that is made up of very fine particles.

Photochemical Smog
Describes the hazy conditions that occur when pollutants are trapped at ground level.

Photosynthesis
The use of sunlight, carbon dioxide and water by plants to grow.

Pollutants
Substances that can damage the air, water or land when released into it.

Pollution
Harmful substances in the environment.

Pores
A small opening in the skin or outer surface of a plant or animal.

Primary Air Pollutant
Pollutants released directly into the air.

Secondary Air Pollutant
Pollutants formed in the air by the mixing of primary air pollutants.

Sulphur Dioxide
A polluting gas produced when fossil fuels are burned.

Sulphuric acid
A component of acid rain formed when sulphur dioxide pollution mixes with moisture in the air.

Wet Deposition
Any gas or particle that falls to the ground after it has mixed or reacted with water, forming acids.