The environment is the surroundings and/or conditions in which persons, animals and plants live. It is comprised of biotic
(plants and animals) and abiotic (water, air etc) factors.
Pollution & Pollutants
Pollution is the contamination of any feature in the environment, ie. the presence in or introduction to the environment of
a (foreign) substance which has harmful or poisonous effects that the environment cannot cope with.
A pollutant is a harmful substance emitted in to the environment that contaminates the environment or atmosphere ie.
material that can be toxic and interferes with the food chain or changes the rate of species growth of plants and animals.
Examples of pollutants:
• Carbon dioxide
• Carbon monoxide
• Soot (carbon particles)
• Oxides of nitrogen
• Lead and its compounds
• Phosphates and Nitrates
• Pesticides and herbicides
• Sulphur dioxide
Sources of Pollution
Three common sources of pollution are:
• Combustion of fossil fuels
• Aerosols and Refrigerants
Sources of the Pollutants
• Combustion of Fossil Fuels: Carbon dioxide & Carbon Monoxide
Carbon monoxide is produced through the incomplete combustion of fossil fuels, while Carbon dioxide is produced when
fossil fuels undergo complete combustion.
Complete combustion of Methane:
Complete combustion of Gasoline:
• Oxides of Nitrogen: Nitrogen Monoxide & Nitrogen Dioxide
• Aerosols and Refrigeration: Chlorofluorocarbons (CFCs)
This pollutant is a small group of molecules in which Chlorine and Fluorine are attached to a small carbon frame work.
CFCs are ideal for refrigerants and aerosols because they have a low boiling point and can be liquified by small amount of
• Fertilizers: Phosphates and Nitrates
Phosphates are found in fertilizers as calcium phosphate and ammonium phosphate they increase phosphorous content in
soil since this needed for photosynthesis.
Nitrates are also found in fertilizers and they are needed for protein synthesis and proper plant growth. Common nitrates
found in fertilizers are potassium, ammonium and calcium nitrate.
Effects of Pollutants on the Environment
• Carbon dioxide - The excess carbon dioxide from the natural carbon cycle accumulates in the atmosphere. Since carbon
dioxide is a 'greenhouse gas', it traps heat radiating from the earth. This creates a 'greenhouse effect' and temperatures
would rise. In addition to that, the carbon dioxide in the air mixes with the water in the atmosphere forming carbonic
acid. This hinders soil acidity and plant growth and can affect limestone environments over time.
Classification of Household Waste
Solid household waste can be separated into biodegradable, recyclable and toxic waste.
• Biodegradable household waste are materials that are decomposed by living organisms such as bacteria. Examples of
such waste include vegetable peels from the kitchen and farm waste.
• On a similar note, recyclable household waste are materials that can be processed into new materials to reduce the
consumption of raw materials. Examples of recyclable waste are paper, plastic, cans, glass and textiles.
• In contrast to the latter classes of household waste, toxic household waste are materials that are considered to be