Excess air can be minimised by adjusting the air flowrate in proportion to the fuel flowrate. This is greatly assisted by the automated measurement of oxygen content in the flue-gases. Depending on how fast the heat demand of the process fluctuates, excess air can be manually set or automatically controlled. Too low an air level causes extinction of the flame, then re-ignition and backfire causing damage to the installation. For safety reasons, there should therefore always be some excess air present (typically 1 – 2 % for gas and 10 % for liquid fuels).
過量空氣可依照製程變動之熱能變換速度需求以人手設定或自動方式控制。過量空氣太少會導致火焰熄火，有復燃或回火現象產生，造成設施損毀；空氣太多則易造成NOX的排放增加。是以，為安全故燃燒時需有適量之過量空氣供應，通常燃氣要1~2%、燃油要10%。(譯註:燃煤要12~20%)。過量空氣可以調整燃料流入量和燃燒空氣使用量的比例調整，使其減少到最低量，同時也可透過煙氣中含氧量的自動量測協助調整。
As excess air is reduced, unburnt components like carbonaceous particulates, carbon monoxide and hydrocarbons are formed and may exceed emission limit values. This limits the possibility of energy efficiency gain by reducing excess air. In practice, excess air is adjusted to values where emissions are below the limit value.
在過量空氣減少後，未燃燒成分如碳粒子、一氧化碳或碳氫化合物可能會形成而超出排放管制量，此點可能使原想透過減少過量空氣達到節能的作法受到限制。實務上，減少過量空氣可調整至汙染排放的管制水準以下。
The minimum excess air that is reachable to maintain emissions within the limit depends on the burner and the process.
Note that the excess air will increase when burning solid wastes. However, waste incinerators are constructed to provide the service of waste combustion, and are optimised to waste as fuel.
過量空氣的最低值可維持排放量在依製程和燃燒器性能訂定的管制範圍內。
需注意的是過量空氣在使用固體燃料時會增加，但廢棄物焚化爐是建造用以燃燒廢棄物的，因此過量空氣應依廢棄物燃料的種類做最適化調整。
The choice of fuels is often based on cost and may also be influenced by legislation and regulations.
燃料的選擇通常基於經濟因素考量，有時會受立法或環境法規的限制及影響。
Energy Efficiency (2009) 3.1.3
