Absorption Efficiency Assessment and Uncertainty Measurement of the Sodium Arsenite Method for Ambient NO2 Determination

Development and validation of a nitrogen dioxide passive sampler

“…In this procedure, the concentration of absorbed nitrite ions during sampling is gauged via colorimetry. This is achieved by subjecting nitrite ions to a reaction with phosphoric acid, sulfanilamide, and N-(1-naphthyl) ethylenediamine dihydrochloride (NEDA), followed by the measurement of absorbance of the resultant azo-dye at 510 nm [13] , [14] , [15] .…”

“…Upon connecting the impingers to the environmental pump, operating at a flow rate of 142 mL/min, a 24 h sampling was conducted at a height of 2 m from ground level. Following the completion of sampling, the absorbent solution was transferred from the impingers into a graduated vial and maintained at a temperature of 4 C until analysis, ensuring the preservation of the cold chain [13 , 14] .…”

“…To mitigate potential sources of error such as chemical and environmental contamination, a control sample was devised by employing the same sample preparation methodology. This involved transferring 10 mL of an absorbent solution that had not been exposed to the ambient air into a vial, followed by the continuation of the remaining sample preparation procedures as delineated earlier [13 , 14] .…”