As the lungs exhale this waste, gas is expelled into the atmosphere.

当肺呼出这股废气，气体就被排到空气中。

《柯林斯英汉双解大词典》

A study by the University of Manchester calculated the emissions of CO2—the main greenhouse gas responsible for climate change—at every stage of microwaves, from manufacture to waste disposal.

曼彻斯特大学的一项研究计算了二氧化碳（造成气候变化的主要温室气体）在微波炉生产的每个阶段的排放量，从产品制造到废物处理。

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As the waste materials decompose, they produce methane gas.

废物腐烂时会产生沼气。

《牛津词典》

For example,animal waste and cattle digestive systems release methane gas.

VOA: special.2010.01.05

But in certain landfills, including some accepting the BP cleanup, waste,heat and methane gas produced by decomposition are being used to generate energy.

VOA: standard.2010.08.05

FuelCell Energy touts the ability of its fuel cells to directly process a hydrocarbon, such as natural gas or waste gas from a sewage treatment facility.

FORBES: Beltway Bet: FuelCell Energy

Chris Wick, from the Environment Agency, said landfill sites generated gas when waste broke down but 2012 had been exceptionally wet and it was believed heavy rain had increased the gas produced.

BBC: Landfill site (generic)

In some markets, some of the time, biomass, geothermal, landfill gas and waste-to-energy can compete on price with carbon-based fuels.

ECONOMIST: When virtue pays a premium | The