Carbon dioxide equivalent of carbon dioxide. Equivalent (e) is the concentration of that would cause the same level of radiative forcing as a given type and concentration of greenhouse gas. Examples of such greenhouse gases are methane, perfluorocarbons, and nitrous oxide. e is expressed as parts per million by volume, ppmv. Carbon dioxide equivalent Carbon dioxide equivalent (CDE) and equivalent carbon dioxide (e and eq) are two related but distinct measures for describing how much global warming a given type and amount of greenhouse gas may cause, using the functionally equivalent amount or concentration of carbon dioxide () as the reference. Carbon dioxide
Nitrous oxide used by almost half a million young people at nightspots, festivals, and parties. The legality of that use varies greatly from country to country, and even from city to city in some countries. The major safety hazards of nitrous oxide come from the fact that it is a compressed liquefied gas, an asphyxiation risk, and a dissociative anaesthetic. While relatively non-toxic, nitrous oxide has a number of recognized ill effects on human health, whether through breathing it in or by contact of the liquid with skin or eyes. Nitrous oxide is a significant occupational hazard for surgeons, dentists, and nurses.