To convert the oil content in air from mass concentration units (mg/m & sup3;) to volume concentration units (ppm), the following formula is used:
ppm = molecular weight of gas mg/m3 × 22.4
step analysis:
parameter confirmation:
- of oil mass concentration10mg/m3.
- standard molar volume is 22.4L/mol (gas volume at standard temperature and pressure).
- molecular weight of oil it needs to be determined according to the specific composition, which is assumed to be 100g/mol (approximate value for common hydrocarbons).
substitute formula calculation:
ppm=10010×22.4 =2.24
conclusion:
when the oil content in the air is 10mg/m3, it is approximately equal 2.24 ppm.
Precautions:
- the molecular weight of the actual oil may vary slightly depending on the composition (for example, the molecular weight of paraffin oil is about 80 & minus;100g/mol), and the calculation results need to be adjusted according to the molecular weight of the specific oil.
- If higher accuracy is required, the influence of environmental factors such as temperature and pressure on the gas volume should be considered.
