According to the CPCB (Central pollution control board) the methods prescribed for the pollutant gases and the particulate pollutants are very sensitive ones yet percentage of errors are very less. The methods prescribed for the gases SO2, NOx and the particulate pollutants TSP, PM10 are respectively:-
(i) Modified West and Gaeke method (SO₂)
(ii) Modified Jacob Hochheiser method (NO₂)
(iii) High Volume method
(iv) Respirable dust sampler (PM₁₀)
(V) Collection of data and analysis from Agra city
METHOD FOR DETERMINATION OF SO2 AT AGRA
Instrument/Equipment:
Modified West and Gaeke method the monitoring and analysis of nitrogen dioxide in ambient air:
Principle:
Modified West & Gaeke Method (IS 5182 Part 2 Method of …show more content…
Principle:
Principle of the method Modified Jacobs & Hochheiser Method (IS 5182 Part 6 Methods for Measurement of Air Pollution: Oxides of nitrogen). Ambient nitrogen dioxide (NO2) is collected by bubbling air through a solution of sodium hydroxide and sodium arsenite. The concentration of nitrite ion (NO- 2) produced during sampling is determined calorimetrically by reacting the nitrite ion with phosphoric acid, sulfanilamide, and N-(1-naphthyl)- ethylene diamine di-hydrochloride (NEDA) and measuring the absorbance of the highly colored azo-dye at 540 n m.
Calculation:
C (NO2 µg/m3) = (As – Ab) x CF x Vs/ Va x Vt x 0.82
Where,
C NO2 = Concentration of Nitrogen dioxide, µg/m3 As = Absorbance of sample Ab = Absorbance of reagent blank
CF = Calibration factor Va = Volume of air sampled, …show more content…
Wf = Final weight of filter in g.
V = Volume of air sampled in cu-m
106 = Conversion of g to μg.
MEASUREMENT OF RESPIRABLE SUSPENDED MATTER (PM10) AT AGRA:-
Instrument:
Respirable dust sampler
Principle:
Air is drawn through a size-selective inlet and through a 20.3 x 25.4 cm (8 x 10 in) filter at a flow rate which is typically 1132 L/min. Particles with aerodynamic diameter less than the cut point of the inlet are collected by the filter. The mass of these particles is determined by the difference in filter weights prior to and after sampling. The concentration of PM10 in the designated size range is calculated by dividing the weight gain of the filter by the volume of air sampled.
Scope:
This method is applicable for measurement of PM10 (Respirable suspended particulate matter) in the ambient air.
Calculation:
Calculation of volume of air sampled V=QT
Where,
V=Volume of air sampled in cu-m.
Q= Average flow rate in cu-m/min
T= Total sampling time in min
Calculation of PM10 in Ambient air (Wp+Wf) - (Wi+Wj) PM10 = ____________________ ×