Ambient Air quality Monitoring Guidlines. - Maharashtra Pollution ...

(A - Ao) (10 3 ) (B)
C = ------------------------- x D
Vr
Where :
A - Sample absorbance
Ao - Reagent blank absorbance
10 3 - Conversion of litres to cubic metres
Vr - Volume of air corrected to 25 o C and 760 mm Hg, litres
B - Calibration factor, µg/absorbance unit
D - Dilution factor
9.5 The Concentration of SO2 in µg/m 3 in the sample is calculated as follows:
(A - Ao) x 10 3 x B
C (SO2 µg/m 3 ) = ------------------------
V
Where :
A - Sample absorbance
Ao - Reagent blank absorbance
10 3 - Conversion litres to cubic meters
B - Calibration factor, µg/absorbance
V - Volume of air sampled in liters
9.6 Conversion of Micrograms per Cubic Metre to Parts per Million
If desired, the concentration of sulphur dioxide may be calculated as parts per
million of sulphur dioxide at reference conditions as follows :
9.7 Precision and Accuracy
ppm SO2 = µg SO2/m 3 x 3.82 x 10 -4
Relative standard deviation at the 95% level in 4.6% for the analytical procedure
using standard samples.
9.0 REFERENCES
1. Indian Standard IS :5182 (Part 2), 2001’ Methods for Measurement of Air Pollution
Part 2 Sulphur Dioxide.
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