Mg/m³ and ppm – SKC Limited AirChek 3000 Deluxe Pump Step By Step Guide User Manual
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224-G1 Issue D
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mg/m³ and ppm
1 part per million (ppm)
is approximately the same as the contents of a party balloon
compared to the volume of air inside 50 three bedroom houses
1 milligram per cubic metre (mg/m³)
is approximately the same as one teaspoon of dust spread over the
area of a football (soccer) field to a height of one metre
X 1
X 50
Teaspoon
1 metre high
Concentrations are expressed as mg/m³ for
solids or parts per million (ppm) for gases. For
example 1 ppm of a gas means that 1 unit
of the gas is present for every 1 million units
of air. It is not always easy to picture what
1ppm actually means, so the diagram below
may help to get some idea of the scale. The
analogies shown are approximate but do give
a reasonable representation of concentration.
If it is considered that the exposure limit for any
kind of dust is 10mg/m³ the comparison of 1
teaspoon of dust over a football field shows
how little this really is.
There is a move to express concentrations
of gas as mg/m³ so we have also included a
conversion formula in the BASIC FORMULAE
section on page 4 of this guide.