Landfills emit significant amounts of gas over a long period of time, with small landfills emitting up to 400 cubic meters of gas per hour and larger landfills emitting up to 10,000 cubic meters of gas per hour. These emissions continue for several years after the landfill closes and doesn't receive any more waste, in most cases for more than 20 years. By simply flaring (burning) the gas, emissions can be reduced by about 90%