parts per million

基本解释

The light reflected by the newfound extrasolar planet, or exoplanet, changed by only about 6.5 parts per million, relative to the brightness of the host star.
這顆新發現的太陽系外行星——或者稱爲外行星——所反射的光線變化相對於其恒星的亮度衹有百萬分之6.5。
At 250 parts per million CO2, the shellfish grew vigorously, and at 750 ppm and higher they were crippled, feeble creatures with thin shells and weak connective tissues.
在 CO2 含量爲百萬分之 250 時，甲殼類生物生長得很好，而到了百萬分之 750 或更高時，它們的甲殼變薄、連結物質變弱，成了殘破而虛弱的生物。
They added that concentrations of carbon dioxide, the main greenhouse gas, should be limited to 350 parts per million of the atmosphere -- below current levels of 387 ppm.
同時應該把大氣中二氧化碳的含量應該控制在百萬分之350個單位，目前的含量水平爲百萬分之387個單位。

The team found levels of lead as high as thirty-two thousand parts per million in tests on some paint samples from Ecuador.
Breathing in two hundred parts per million of carbon monoxide will cause the first signs of poisoning.
Twelve thousand parts per million of the gas will cause death in one to three minutes.

Floating sensors hold the oxygen to between 2 and 2.5 parts per million of water.
FORBES: Muckraker