What is the concentration of Carbon Dioxide (CO2) in dry air, expressed in parts per million (ppm)?

Answer

42 ppm

Carbon Dioxide is present at levels around 42 ppm, or 0.0042% by volume in dry air, despite its significance as a greenhouse gas.

What is the concentration of Carbon Dioxide (CO2) in dry air, expressed in parts per million (ppm)?
atmosphereGasesabundance