emission
/ɪˈmɪʃən/noun
mass noun
1- the production and discharge of something, especially gas or radiation（尤指气体或辐射的）发出, 散发, 排放：
the effects of lead emission on health
铅排放对健康的影响
count noun cuts in carbon dioxide emissions.二氧化碳排放量的减少。
1.1
- count noun an ejaculation of semen射精, 遗精。
词源
late Middle English (in the sense emanation)： from Latin emissio （n -）, from emiss - 'sent out', from the verb emittere （see EMIT）.