Zero air refers to air that has been purified. For it to be classed as zero air it must contain less than 0.1 PPM of total hydrocarbons. The letters PPM stand for parts per million.
A hydrocarbon is a compound that contains only hydrogen and carbon. Hydrocarbons are the main components of natural gas and petroleum. Methane, for example, is a hydrocarbon. Its chemical formula is CH4, which means that it consists of one carbon atom and four hydrogen atoms. Propane (C3H8) and ethane (C2H6) are also hydrocarbons. We create this ultra-purified air by mixing pure oxygen with pure nitrogen, thereby getting rid of all the impurities that exist in ambient air.