INFO:

What are Greenhouse Gas Emissions? Emissions are substances released into the air and are measured by their concentrations, or parts per million, in the atmosphere. The main greenhouse gases are water vapor (H20), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6).