常见消毒用的含氯化合物如漂白粉、氯胺T、一氯胺和二氧化氯等的有效成分,均以“有效氯”(av-ailable chlorine)%或“活性氯”(active chlorine)%来表示。“有效氯”和“活性氯”是两个不同的概念,在大多数含氯化合物中,两者的值并不相等。但是在一些专业书中对它们的记载有误,其原因可能是把两者的含义混淆,或认为“活性氯”是“有效氯”的同义词。如有的书叙述氯胺T的“有效氯”含量约为25%,或含“活性氯”11.5～13%都是正确的;而在另一些书中,介绍它的“有效氯”含量为11.5～13%则是错误的,两数相差一倍,致使一些基层工作人员造成误会。为了说明以上问题,首先应把“活性氯”和“有效氯”的含义弄清。在含氯的化合物中,氯原子的化 Chlorine compounds commonly used for disinfection such as bleach, chloramine T, monochloramine and chlorine dioxide and other active ingredients are “effective chlorine” (av-ailable chlorine) or “active chlorine” chlorine)% to represent. “Effective chlorine” and “active chlorine” are two different concepts. In most chlorine-containing compounds, the values ​​of the two are not equal. However, in some professional books they are incorrectly documented, either because of the confusion between the two, or because “active chlorine” is synonymous with “effective chlorine.” Some books describe that the effective chlorine content of chloramines T is about 25% or that the effective chlorine content is between 11.5% and 13%, while in other books it is introduced. Effective chlorine “content of 11.5 to 13% is wrong, the difference between the two doubled, resulting in some grassroots staff misunderstanding. In order to explain the above problems, we should first clarify the meaning of ”active chlorine“ and ”effective chlorine". Chlorine-containing compounds, the chlorine atomization