Analytical · Glossary

What is ppm to mg/m³ Conversion?

gas concentration unitsAnalytical

ppm to mg/m³ conversion turns a gas concentration by volume into mass per volume, using the molar mass and molar volume.

ppm to mg/m³ Conversion Explained

Gas analysers usually read ppm by volume, while emission limits and exposure limits are often in mg/m³. The conversion depends on temperature and pressure.

At 25 °C and 1 atm the molar volume is 24.45 L/mol; at 0 °C it is 22.41 L/mol.

ppm to mg/m³ Conversion Formula

mg/m³ = ppm × M ÷ V_m

M	molar mass (g/mol)
V_m	molar volume (L/mol), 24.45 at 25 °C

Example: 50 ppm CO (M = 28.01) at 25 °C: 50 × 28.01 ÷ 24.45 ≈ 57.3 mg/m³.

Calculators for ppm to mg/m³ Conversion

Calculatorppm to mg/m3 CalculatorFree online calculator with formula and worked example.Calculatorppm to Molarity CalculatorFree online calculator with formula and worked example.CalculatorGas Mixture Molecular Weight CalculatorFree online calculator with formula and worked example.

Frequently Asked Questions

What is ppm to mg/m³ Conversion?

ppm to mg/m³ conversion turns a gas concentration by volume into mass per volume, using the molar mass and molar volume.

Which molar volume for emissions?

Normal conditions, 0 °C and 101.325 kPa, so 22.41 L/mol, unless the permit says otherwise.

Is ppm by volume the same as by mass?

No; gas ppm is normally by volume.

Learn more on the blog

Instrumentation and control standards

A practical guide on instrumentationblog.in with more detail on ppm to mg/m³ conversion and how it is applied on real plants.

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