10
Calculating Concentrations
Formula 2
z
C = Concentration (
μ
g/m
3
) of aldehydes and ketones in the sampled air at the
converted temperature
z
Wa = Quantity (ng) of aldehydes and ketones collected in one active gas tube
z
Wb = Blank value (ng)
z
V= Collected volume at converted temperature (L)
z
Calculation Method in Japan's Ministry of
Health, Labour and Welfare Guidelines
(for reference)
The calculation method indicated in the Ministry of Health, Labour and
Welfare guidelines (Committee on Sick House Syndrome: Indoor Air
Pollution) is shown below.
The method involves graphing the relationship between the injected
quantity of aldehydes and the corresponding peak area or peak height
values and then using that graph as a calibration curve.
The following formula is recommended for calculations if results are to
be compared to indoor air quality guideline values indicated by the
Ministry of Health, Labour and Welfare.
Calculation Formula
Formula 3
z
C = Concentration (
μ
g/m
3
) of aldehydes in the sampled air at 20
°
C
z
As = Mass (
μ
g) of aldehydes in the sample solution, as determined from the
calibration curve
z
A = Mass (
μ
g) of aldehydes in the blank test solution, as determined from the
calibration curve
z
D = Dilution factor
z
E = Volume (
μ
L) of sample solution
z
v = Volume (
μ
L) injected into the HPLC system
z
V = Volume (L) of sample air collected, as measured by a gas meter
z
t = Mean air temperature (
°
C) during sample acquisition, or mean water temperature
(
°
C) of the integrating flow meter (if using a wet-gas type integrating flow meter)
z
p = Mean atmospheric pressure (kPa) during sample acquisition
Use (P - Pw) if using a wet-gas type integrating flow meter. P is the standard
atmospheric pressure (101.3 kPa), whereas Pw is the saturated vapor pressure
(kPa) at t, the mean air temperature during sample acquisition.
