Kj. Hedley et al., AN EVALUATION OF INTEGRATING TECHNIQUES FOR MEASURING ATMOSPHERIC NITROGEN-DIOXIDE, International journal of environmental analytical chemistry, 54(3), 1994, pp. 167-181
Two integrating techniques for measuring ambient NO2 were evaluated. B
oth techniques involved quantitative collection of NO2 in a reagent co
ated cartridge, specifically triethanolamine (TEA)-coated silica gel a
nd diphenyl-amine (DPA)-coated Florisil. The evaluation of these techn
iques consisted of laboratory and field studies. The laboratory studie
s of the TEA method indicated collection and reaction efficiencies of
100 and 90%, respectively. A positive interference occurred when O3 an
d NO were passed through the cartridge simultaneously. PAN was found t
o produce a 67% positive interference. The ambient concentrations dete
rmined using the TEA method were approximately a factor of two higher
than those determined using TDLAS. For the DPA method the collection a
nd reaction efficiencies were determined to be 100 and 64%, respective
ly. O3 produced a negative interference by reacting with the NO2-DPA p
roducts. PAN produced a 42% positive interference. A regression of the
DPA versus TDLAS determined ambient NO2 concentrations yielded a slop
e of .91+/-.08 (r2=0.990.). Neither method was found suitable for netw
ork use in its present form.