parts per million (ppm)

常见例句

One group ate food with 0.3 parts per million (ppm) methylmercury, which most U. S. states would regard as too high for human consumption.
一组的食物含千万份之三的甲基水银，这个含量在美国大多数州都被认为是超出人体承受的。
However, none of the melamine concentrations in the eggs exceeded the FDA's maximum allowable level -- 2.5 parts per million (ppm) in foods.
然而，所产鸡蛋中的三聚氰胺含量都没有超过美国食品与药物管理局设置的最高允许水平——食品中含2.5ppm的三聚氰胺。
Levels of the gas at the Zeppelin research station on Svalbard, northern Norway, last week peaked at over 397 parts per million (ppm), an increase of more than 2.5ppm on 2008.
挪威北部斯瓦尔巴群岛上的齐柏林研究站上周记录的二氧化碳气体水平最高值超过397个百万分点，比2008年的水平增加了2.5个百万分点。

According to Roberto, the wastewater starts with about 35, 000 parts per million (ppm) of gunk and junk.
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Using a technique called secondary ion mass spectrometry, the team determined that the mantle from which the meteorites derived contained between 70 and 300 parts per million (ppm) of water.
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Before we started torching carbon stored in forests and then carbon stored underground as coal and oil, the carbon dioxide concentration of our atmosphere was about 280 parts per million (ppm).
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