A performance evaluation of the open tube diffusion sampler (Palmes sampler) for monitoring nitrogen dioxide

The Palmes sampler is largely used to carry out indicative measurements for NO2 as considered in EU legislation (Daughter Directive 1999/30/EC). In order to comply with the quality objectives set out in this directive it is important that the limits of this technique are fully appreciated. The sampler was tested in a chamber study and in field trials. Experiments were carried out to study the effect of wind turbulence, the stability of the NO2-TEA adduct and the self-consistency of the method. The results of these experiments demonstrated underestimation in comparison to chemiluminescence probably due to photodegradation of the NO2-TEA adduct and/or incomplete extraction of nitrite.