How to calculate concentration in ppbv C

Question

how to calculate [ ] of atmospheric carbon compounds in ppbv C for the following data:

Toluene = 980 ug/m3

Hexane = 150 ug/m3

Answer 1

The general equation is: ppbv = ug/m3 (273.15 +oC) / 12.19 (MW)

(parts per billion by volume)= (micrograms/m3)(273.15 + oC)

/  (12.19)(MW)

without a temperature given, 22  degrees Celsius is is the accepted norm, so the formula becomes:

ppbv = (ug/m3) (295)  / 12.19  (MW)

ppbv= 24.2 (ug/m3) / (MW)

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if you have a different temperature to calculate this at, you need to modify this formula

Toluene = 980 ug/m3 (24.2) / 92.14 g/mol

your answer is 257 ppbv C ,which is  260 ppbv C @ 2 sigfigs

Hexane = 150 ug/m3 (24.2) / 86.18 g/mol

your answer is 42 ppvc  (2 sig figs)

"980" & "15O" have only 2 sigfigs