ppmの記事

Atmospheric CO2 concentration measured at Mauna Loa Observatory in Hawaii from 1958 to 2023 (also called the Keeling Curve). The rise in CO2 over that time period is clearly visible. The concentration is expressed as μmole per mole, or ppm.

二酸化炭素（CO2）が地球環境に与える影響と現状

2026年8月12日続きを読む →

Fluorescein aqueous solutions, diluted from 10000 to 1 part per million in intervals of ten-fold dilution. At 10000 ppm the solution is a deep red colour. As the concentration decreases, the colour becomes greenish-orange, then a vibrant yellowish-green, with the final 1 ppm sample a very pale yellowish-green.

パーツパー表記（ppm/ppb/ppt）の定義と科学的な活用法

2026年8月11日続きを読む →

$Abundance (atom fraction) of the chemical elements in Earth's upper continental crust as a function of atomic number;[5] siderophiles shown in yellow$

地殻元素の存在量地球の組成を決定づける化学的分布

地殻元素存在量ゴールドシュミット分類親鉄元素

2026年8月9日続きを読む →