Carbon dioxide (CO2) comprises two oxygen atoms and one carbon atom, which occurs naturally through the carbon cycle and burning fossil fuels. The carbon cycle refers to the tons of CO2 that oceans and plants remove from the atmosphere. Natural sources release CO2 back into the environment. According to the Environmental Protection Agency, natural sources of CO2 include plants and animal respiration, volcanic eruptions and ocean releases.
The global food industry depends on CO2 for short-term and long-term refrigeration of food products. CO2 not only serves as a refrigerant, but it also acts as an anaerobic agent, which boosts the chemical's value for food preservation purposes. Many food processors use CO2 for individual quick freeze, grinding and commercial packaging.
The Endowment for Medical Research cites university studies that show increasing the level of CO2 to 550 parts per million (ppm) speeds up plant growth as much as 40 per cent in a controlled greenhouse environment. The CO2 levels in the average greenhouse, with a closed ventilation system, decreases to 150 ppm to 200 ppm. During the summer, opening the ventilation system allows fresh air into the greenhouse, which increases the CO2 level. However, during the winter, in northern regions, the circulation of cold outside air into heated greenhouses could kill plants.
Greenhouse Gas Emissions
Greenhouse gases, such as nitrous oxide, methane and CO2, affect the heat flow to and from the earth's atmosphere. Some scientists argue the huge increase in CO2 and other greenhouse gases released into the atmosphere will cause the average worldwide temperature to increase anywhere from -16.6 to -11.3 degrees Celsius by 2100, according to the Environmental Defense Fund. This rise could have negative consequences, including severe droughts and powerful storms.
High indoor levels of CO2 could lead to severe health effects, even death. According to "Current Science" magazine, studies have demonstrated that people can sense a decline in air quality when CO2 levels reach 600 ppm. When CO2 reaches or exceeds this level, then individuals usually begin to demonstrate signs of CO2 poisoning, including a rapid pulse rate, loss of hearing, breathing difficulties and sweating and fatigue.