EU ETS system covers carbon dioxide (CO2) from electricity and heat generation, energy-intensive industry sectors (oil, steel, iron, aluminium, metals, cement, lime, glass, ceramics, pulp, paper, cardboard, acids, bulk organic materials), commercial aviation within the European Economic Area (EEA); nitrous oxide (N2O) from production of nitric, adipic and glyoxylic acids and glyoxal; perfluorocarbons (PCFs) from production of aluminium.