Hydrocarbons contain hydrogen and carbon as a main element of the fuel oil petroleum and natural gas. When we put fuel such as oil, coal and natural gas used as fuel, it will unleash a hydrocarbon. In addition, liquid fuel and gas that we use every day are evaporation from storage tanks, gas oil. Pump operator Guest room account or during refuelling and before the furnace gas is flammable, these have a number of hydrocarbons. Evaporate into the atmosphere with the above reasons.