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General information on gas measurement
Reference

# Concentration unit conversion

Converts gas concentration units to other units.

Input data

Up to eight digits, including digits after the decimal point, can be entered in input fields.

Concentration

Enter the concentration values and select the concentration unit from the pull-down list.

Substance name

Molecular weight

Either directly enter the name of the gas, or select it from the pull-down list. Alternatively, directly enter the molecular weight.

Temperature

ºC

If the temperature is not 20ºC, enter the temperature in the corresponding field.

Pressure

hPa(One atmospheric pressure=1013hPa)

If the pressure is not one atmospheric pressure (1013 hPa), enter the pressure in the corresponding field.

Gas concentration

%

ppm

mg/m3

mg/L

## Units for measuring concentration

### Common units for measuring concentration

% (percent) This unit expresses concentration in parts per hundred (percentage) of a substance in 100mL of a medium such as air. This unit that expresses concentration in parts per million is measured as the volume (denoted in litres [L]) of a substance found in 1L of a medium such as air. This unit expresses the concentration in one cubic metre of air (equivalent to 1L or 1000mL) of a substance in terms of its mass (measured in milligrams). It is primarily used for particle-like substances, and only rarely for gaseous concentrations. This unit expresses the concentration in one litre of air (1000mL) of a substance in terms of its mass (measured in milligrams). It is generally used for measuring concentrations in liquids, and only rarely for gaseous concentrations.

### Converting from one unit of concentration to another

% → ppm ppm=%×10000 → 1ppm=0.0001% %=ppm×1/10000 → 1%=10000ppm mg/m3=ppm× M22.4×273(273+T)×P1013 ppm=mg/m3×22.4M×(273+T)273×1013P %=mg/l×22.4M×(273+T)273×110×1013P mg/l=%×M22.4×273(273+T)×10×P1013
M:
Molecular weight of a substance
22.4(L):
The volume of 1 mol at 1 atmospheric pressure at 0ºC
273(K):
FK stands for Kelvin, the unit used to measure thermodynamic temperature; as 0ºC corresponds to 273.15K.
You simply need to add 273 to the Celsius/Centigrade value (273+T) to obtain the temperature in Kelvin
1013(hPa):
One atmospheric pressure
P:
P denotes the atmospheric pressure at the point of measurement (hPa)