Instruments based on this reaction can provide the
desired time response but depend upon prior conversion of NO2 to NO. This reaction is specific for N O
and the technique can be expanded to measure NO2
by first reducing NO2 to N O and then measuring
total NOx as NO. Unfortunately, the reduction of
NO2 to N O is not specific for NO2, so that other
nitrogen species are also reduced to NO and act as
interferences in the NO2 measurement