LABORATORY TESTS OF KI AND ALKALINE ANNULAR DENUDERS

Annular denuders coated with KI and with alkaline solutions have been tested for their ability to remove atmospheric pollutants including ozone, NO2, SO2, formaldehyde, methyl nitrate and peroxyacetyl nitrate. Tests were carried out at flow rates of 0.4-2.0 ℓ min-1, using particle-free ambient air as well as purified air to study the effect of atmospheric CO2 on alkaline denuder performance. Denuders coated with KI were efficient in removing O3, NO2, SO2 (> 95%) and PAN (84±3%) but not methyl nitrate (44%) and formaldehyde (<5%). Selective removal of PAN from NO2, and vice versa, could be obtained with annular denuders coated with NaOH, which removed 100% PAN and ≤15% NO2, and with alkaline guaiacol, which removed ≥99% NO2 and ≤6% PAN. © 1990.