All along, people have been advocating that natural gas is a green energy, because the natural gas with the main content of methane is less carbon dioxide than coal, gasoline and diesel, so that more and more cars around the world are using methane based natural gas to replace gasoline and diesel as vehicle fuel, and also using natural gas to replace coal for power generation to cities. But is natural gas really that clean*** Recently, a natural gas assessment report in the * * * Education Science Monitor suggested that the carbon emission of natural gas may be 75~25% higher than the expected carbon emission, which is also far lower than that of gasoline and coal. According to the new regulations issued by the US Environmental Protection Agency in 2012, new requirements for reducing methane emissions from oil and gas exploration are proposed, which is expected to reduce methane emissions by at least 1 million tons annually. The authors of this analysis report believe that it cannot be completely determined that natural gas is responsible for these methane emissions. Of course, even if all the extra methane comes from natural gas, in terms of the impact on carbon dioxide greenhouse gas emissions in the next 100 years, replacing gasoline, diesel and coal with natural gas with methane as the main component will still bring considerable benefits. Because the exploitation of natural gas is relatively simple, the subsequent processing also causes less pollution. Secondly, methane, the main component of natural gas, can relatively fully burn to generate water and carbon dioxide, and will not generate carbon monoxide or carbon black, thus causing PM2.5 to exceed the standard. Moreover, natural gas does not need to add lead and benzene as gasoline antiknock agents as gasoline does.