The pre-industrial carbon dioxide amount was 280 parts per million (ppm). Humans, by burning coal, oil and gas, have increased this to 385 ppm; it continues to grow by about 2 ppm per year.
在前工业时代，二氧化碳含量为280ppm，人类燃烧煤炭和油气的行为使其上升到385ppm，而这一数值还在以每年2ppm的速率增长。
Hitherto diesel contained up to 500 parts per million (ppm) of sulphur, but the new rules limit sulphur to 15 ppm.
目前，柴油中硫含量为500ppm，但新规定将其限制在15ppm。
应用推荐