Carbon dioxide equivalent of "emissions" or rate of greenhouse gas emission—a "flow" into the atmosphere—rather than the instantaneous value of the radiative forcing of the "stock" (concentration) of greenhouse gases "in the atmosphere" described by e. The carbon dioxide equivalency for a gas is obtained by multiplying the mass and the GWP of the gas. The following units are commonly used: For example, the GWP for methane over 100 years is 34 and for nitrous oxide 298. This means that emissions of 1 million metric tonnes of methane and nitrous oxide respectively is equivalent to emissions of 34 and 298 million metric tonnes
Nitrous oxide engine not be permitted for street or highway use, depending on local regulations. Nitrous oxide use is permitted in certain classes of auto racing. Reliable operation of an engine with nitrous injection requires careful attention to the strength of engine components and to the accuracy of the mixing systems, otherwise destructive detonations or exceeding engineered component maximums may occur. Nitrous oxide injection systems were applied as early as World War II for certain aircraft engines. In the context of racing, nitrous oxide is often termed nitrous or NOS. The term NOS is derived from the initials of the company name Nitrous