Field methods for the determination of nitrogen dioxide in air

The oxides of nitrogen and their detection in automotive exhaust

“…These problems were partially alleviated by Christie, el at. (10), who added glycerol as a humectant during preparation of the test papers. Storage life was increased to 3 mon and the effect of humidity at normal levels was minimized.…”

Measurement of sub-ppb by volume levels of atmospheric nitrogen dioxide using an alkaline trapping solution and spectrofluorometric analysis

“…This formulation was chosen over the ones reported by Mulik et al ( 11) based upon the work of Nash (12), because the 2methoxyphenol present in the sampling solution interfered with the analysis. The arsenic-type trapping solution developed by Christie et al (13) was not checked for suitability.…”

“…The bubbler contained 13 ml of the trapping solution developed by Huygen and Steerman (6) which consisted of 0.1 N NaOH, 0.02% 2-naphthol-3,6-disulfonic acid disodium (d-naphthol), and 0.124% triethanolamine hydrochloride.…”

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

“…Shy et al (1970) calculated an efficiency factor as low as 0.27 at 1 ppm NO2 concentration and a factor of 0.695 at much lower concentration (0.056 ppm) using the same method. Christie et al (1970) found a high recovery of 94% while using 5.8 ppm of standard NO2 gas at 0.12 lpm sampling flow rate (with sodium arsenite in absorbing solution). Merryman et al (1973) reported an average efficiency of 89.7% using 2-impinger system at 0.465 lpm which was similar to the work reported by Jacobs and Hochheiser but with the use of 0.1% sodium arsenite in absorbing solution.…”