Carbon dioxide, CO2
Carbon dioxide is a colourless, odourless gas, denser than air that occurs naturally in the earth's atmosphere. It is slightly soluble in water, forming carbonic acid.
Carbon dioxide has many uses, such as a coolant, fire extinguishing gas and preservative. The gas is also used to provide the bubbles in fizzy drinks. A minor use of the solid (frozen) form is to produce smoke effects in TV, film and theatre.
Carbon dioxide is released in large quantities from natural processes, notably respiration by living organisms. Releases from respiration are balanced by a similar quantity taken up by photosynthesis. Other natural sources of carbon dioxide include volcanoes, forest fires and evaporation from seawater. Man made carbon dioxide is produced by combustion processes and released to the atmosphere in chimney emissions from power stations, motor vehicles and other processes where fuels containing carbon are burnt.
The concentration of carbon dioxide has increased by around 30% since the industrial revolution, mainly as a result of the combustion of fossil fuels.
Impacts on human health and environment
Excessive exposure to carbon dioxide can affect the brain and ultimately leads to suffocation. The main environmental concern with carbon dioxide is the role this compound plays as a greenhouse gas influencing climate change.
Emission to air reporting threshold: 100000000 kg/year
Data source: European Pollutant Emission Register