臭味是如何形成的呢？

Yes , most unpleasant odors come from decaying of matter by the action of bacteria . So under the favour conditions such humid , hot temperature & with oxygen or without oxygen , different types of microorganisms feed on the substances which changes to food to the bacteria , & will generate some by products that usually toxic & malodor . This is the source of bad odor . However take Hydrogen sulfide H2S--rotten egg smell which is from decaying protein but you can generate H2S by using the combination of hydrogen & sulphur too .For H2S , at low concentration one can detect the bad smell so the body gives you a warning to go away before the smell will endanger your body , this is a natural defense of our body ! At higher concentration of H2S , you cannot detect the smell but it is fatal to you ! So malodor will not decrease if the conditions favour for the bad smell . For dead mouse smell will last for a long time , unless you remove the dead mouse . Usually it just requires 1or 2 parts per million in the air that you can detect the bad smell . If there is no more dead mouse , you are right about the bad smell will get less & less, no more !

第一個說法正確,有機物被細菌分解時會產生氣味,當中不少是刺激性的,例如有機酸,酯,甚至一些硫化物都會刺激鼻腔嗅覺神經細胞,再轉變成神經脈衝傳送到大腦感受,但要視乎分解物的成份而產生什麼氣味,而且產物不一定是氣體,只有分子小的物質才會揮發到空氣中讓我們嗅到
至於第二說法有點不完全,若果是指分解物的體積那是正確的,因為分解物是不斷地被細菌轉化出能量和其他物質,其他物質當然包括揮發出的氣體,正如屍體腐爛,體積是不斷減少,最後餘下難以分解的骨骼