Word · Frequency #17833
ppm
百万分率
核心释义
parts per million
用法In use
The carbon dioxide level in the room was measured at 800 ppm.
用法提示：ppm 是“百万分率”的缩写，在此句中跟在数字后作单位名词。
The water quality report showed that the chlorine concentration remained below 0.5 ppm.
用法提示：ppm 表示百万分率，在句中作为浓度单位使用。
Farmers often use a solution with 100 ppm of nitrogen to feed the plants.
用法提示：ppm 是 parts per million 的缩写，这里指百万分率，作名词性单位。
[number] ppm
ppm 是 parts per million 的缩写，数字直接放在 ppm 前面。
The safe level is 50 ppm.
安全水平是50 ppm。
be measured in ppm
measure 常用被动语态，表示“以…为单位测量”。
Carbon monoxide levels are measured in ppm.
一氧化碳含量以ppm为单位测量。
X ppm of [substance]
介词 of 后接被测物质，表示“…的浓度”。
The soil contains 120 ppm of zinc.
土壤含有120 ppm的锌。
常见错误Common mistakes
易错句子The concentration of CO2 is 400 ppms.正确表达The concentration of CO2 is 400 ppm.
ppm 是 parts per million 的缩写，作为计量单位直接跟随数字，没有单复数变化，不能加 -s。
易错句子The safe level of lead is 5ppm.正确表达The safe level of lead is 5 ppm.
英文中数字与单位缩写之间通常要留一个空格，5ppm 不符合书写规范，应写成 5 ppm。
相关词与表达Connections
搭配Collocations
- ppm levels
- 百万分率水平
- The ppm levels in the drinking water were above the safety limit.饮用水中的百万分率水平超过了安全限值。
- measured in ppm
- 以百万分率测量
- Most air pollutant concentrations are measured in ppm.大多数空气污染物浓度都以百万分率测量。
- ppm concentration
- 百万分率浓度
- The carbon dioxide ppm concentration in the atmosphere has been rising.大气中的二氧化碳百万分率浓度一直在上升。
- ppm range
- 百万分率范围
- The test result fell within the expected ppm range.测试结果落在预期的百万分率范围内。
学习提示Learner notes
记忆技巧Memory Tip
ppm 里两个 p 夹一个 m：p 是 part（份），m 是 million（百万）——一份在百万份里。
语境与语域Context & Register
语域：formal 常见场景：scientific reports、environmental monitoring、laboratory analysis ppm 多用于科学、工程或环保监测等正式场合，表示百万分率。日常口语中较少使用。
发音与拼写Pronunciation & Spelling
ppm is read letter by letter: /ˌpiː piː ˈɛm/. The final stressed syllable /ɛm/ genuinely rhymes with them, gem, hem, and stem. Beware lookalikes such as calm and firm: they also end in m, but calm has /ɑːm/ and firm has /ɜːm/, so they do not rhyme with ppm.
Dictionary facts from ECDICT, WIKTIONARY.