Gas concentration: ppm ↔ mg/m³
Mass concentration of a gas or vapour from its volume concentration (ppm) at a given temperature and pressure, the reverse factor and the ratio to the exposure limit.
C = c · M · P / (R · T)k = M · P / (R · T): 1 ppm = k mg/m³V_m = R · T / P; C / LIdeal gas law: at 101.325 kPa a mole of gas takes 24.055 L at 20 °C, 24.465 L at 25 °C and 22.414 L at 0 °C, so the same ppm gives different mg/m³. The limits are from the hygienic standards for air (Order of the Minister of Health No. ҚР ДСМ-70 of 02.08.2022): Annex 1, Table 1, limits in the ambient air of settlements (one-time maximum and daily average); Table 2, tentative safe exposure levels; Annex 2, workplace air limits.
Source: Ideal gas law; hygienic standards for air, Order of the Minister of Health of Kazakhstan No. ҚР ДСМ-70 of 02.08.2022 (reg. No. 29011)
Inputs
You can change a field's unit: the value is converted to the formula's units automatically.
Gas detector reading; 1 vol. % = 10,000 ppm.
H₂S 34.08, SO₂ 64.06, NO₂ 46.01, CO 28.01, CH₄ 16.04 g/mol, or pick a substance in the presets.
Usually 20 °C for workplace air; 0 °C for normal conditions.
Hydrogen sulphide: workplace air 10 mg/m³ (3 mg/m³ mixed with C₁–C₅ hydrocarbons); ambient air in settlements, one-time maximum 0.008 mg/m³.
Unit converter for this formulaTemperature · Pressure
- °C20
- K293.15
- °F68
- °R527.67
°F = °C × 1.8 + 32; K = °C + 273.15.
- k — 1 ppm equals–mg/m³
- 1/k — 1 mg/m³ equals–ppm
- V_m — Molar volume of the gas–L/mol
- C/L — Ratio to the limit–
More in Air quality
Results are engineering estimates from standard formulas; for design decisions check them against the codes, project documents and specialists' calculations. The formulas carried over from the original set are unchanged, and their errors are described in the notes.