“Greenhouse gas” is a term for gases in Earth’s atmosphere that trap energy from the sun. Greenhouse gases can be divided into two categories: those that occur naturally, and those that humans have introduced into the atmosphere.
Naturally Occurring Greenhouse Gases:
- Carbon Dioxide(CO2) – produced naturally by any organism or microorganism that utilizes plant matter as part of their diet. It is also consumed by plants during respiration. It can also be released into the atmosphere during several chemical processes such as the combustion of coal and other fossil fuels.
- Methane(CH4) – a gas that exists, among other places, in deposits in the ocean floors and under the earth’s crust. It also is produced in the metabolism process during the decay of organic matter.
- Nitrous Oxide(N2O) – a chemical compound also know as happy gas(!). According to the EPA, it is produced naturally “from a wide variety of biological sources in soil and water, particularly microbial action in wet tropical forests”. It is also introduced unnaturally through fertilizers and sewage treatment.
An Alder leaf showing ozone discoloration
- Ozone(O3) – Ozone exists naturally in the ozone layer in Earth’s atmosphere. It helps filters ultraviolet light from reaching the surface. However, at ground level it can be a harmful pollutant and affect respiratory function. It is often used as an oxidizing agent in chemical reactions.
- Water Vapor – Water vapor is simply the gas phase of water.
Introduced Greenhouse Gases
- Hydrofluorocarbons (HFCs) and Perfluorocarbons (PFCs) – chemical compounds known as haloalkanes often used as a refrigerant. According to this article from the Environmental Investigation Agency: “HFCs are “super” greenhouse gases, with global warming impacts hundreds to thousands of times higher than CO2″
- Sulfur Hexafluoride (SF6) – A manmade gas that is used mostly in the electrical industry.
Other sources:
National Polutant Inventory – Fluoride and compounds fact sheet
EPA – Greenhouse Gas Emissions
