ppm to mg/m³ Gas Concentration Converter
Convert gas concentration between ppm by volume and mg/m³ at any temperature and pressure, for emissions, gas detection and analyser work.
- Vm = 22.414 × (T ÷ 273.15) × (1.01325 ÷ P) = 24.465 L/mol
- mg/m³ = ppm × M ÷ Vm = 261.86
Conversion Formula
Vm = 22.414 L/mol at 0 °C, 1.01325 bar; 24.45 L/mol at 25 °C
Emission limits are usually given in mg/Nm³ at 0 °C (sometimes with a reference oxygen content); occupational exposure limits at 25 °C. Use the matching reference conditions.
Worked example
100 ppm SO₂ at 25 °C and 1 atm is 100 × 64.07 ÷ 24.47 = 262 mg/m³; at 0 °C (mg/Nm³) it is 286 mg/Nm³.
Frequently Asked Questions
How do I convert ppm to mg/m³?
Multiply ppm by the molar mass and divide by the molar volume: 24.45 L/mol at 25 °C or 22.41 L/mol at 0 °C.
What is 1 ppm of CO in mg/m³?
About 1.15 mg/m³ at 25 °C.
Is ppm by volume the same as ppm by mass?
No. Gas ppm is normally by volume (mole fraction).
Learn more on the blog
Instrumentation and control standards
A practical, field focused guide on instrumentationblog.in that explains the theory behind this calculator and how engineers apply it on real plants.
Read Full Article