Carbon dioxide (CO2) is a chemical compound with the chemical formula CO2. It is made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. CO2 is a versatile industrial material, used, for example, as an inert gas in welding and fire extinguishers, as a pressurizing gas in air guns and oil recovery, and as a supercritical fluid solvent in decaffeination of coffee and supercritical drying. It is a byproduct of fermentation of sugars in bread, beer, and wine making, and is added to carbonated beverages like seltzer and beer for effervescence.
In Earths atmosphere, carbon dioxide is a trace gas that plays an integral part in the greenhouse effect, carbon cycle, photosynthesis, and oceanic carbon cycle. It is one of several greenhouse gases in the atmosphere of Earth. Carbon dioxide is an important heat-trapping gas, also known as a greenhouse gas, that comes from the extraction and burning of fossil fuels (such as coal, oil, and natural gas), from wildfires, and natural processes like volcanic eruptions. The current global average concentration of CO2 in the atmosphere is 421 ppm as of May 2022 (0.04%) . This is an increase of 50% since the start of the Industrial Revolution.
Carbon dioxide is also important for life on Earth because plants use it to produce carbohydrates in a process called photosynthesis. Since humans and animals depend on plants for food, photosynthesis is necessary for the survival of life on Earth. However, as CO2 builds up in our atmosphere from burning fossil fuels, it has a warming effect that could change the Earth’s climate. Indoor carbon dioxide concentrations are driven by a combination of outdoor CO2, indoor breathing, and the ventilation rate of the building. As buildings and homes become more energy-efficient and airtight, CO2 levels concentrate indoors with less ventilation.
