co2能不能用排空气法？

CO2 cannot be captured or removed from the air using the combustion of fossil fuels or other substances since it is already present in the atmosphere in a gaseous state. Therefore， the method of exhaust air is not a feasible or desirable method for reducing CO2 emissions.

There are other technologies or methods available to capture or remove CO2 from the atmosphere. Some of these methods include carbon capture and storage， afforestation， and bioenergy with carbon capture and storage.

Carbon capture and storage (CCS) is a system where carbon dioxide emitted from power plants or industrial facilities is captured and transported to storage sites or used for enhanced oil recovery. The aim is to prevent CO2 from being emitted into the atmosphere， where it contributes to climate change.

Afforestation is the process of planting trees in areas where there was previously no forest. Trees absorb CO2 during photosynthesis， so afforestation can help to reduce CO2 levels in the atmosphere.

Bioenergy with carbon capture and storage (BECCS) is a method where crops or wood are used to produce energy， but the CO2 emissions are captured and stored so that the process becomes carbon neutral or even carbon negative.

In summary， while the exhaust air method cannot be used to remove CO2 from the atmosphere， there are other methods available that can help to reduce CO2 levels and mitigate the effects of climate change.