Development of highly sensitive passive sampler for nitrogen dioxide using porous polyethylene membrane filter as turbulence limiting diffuser

A new design of passive sampler is described which is appropriate to reduce the sampling resolution of most formats of Palmes’ tubes from weeks to 24 h or less. The sampler employs a flat-type porous polyethylene membrane filter as a diffuser, which controls mass transfer of the target analyte from ambient air to impregnated trapping filter. The new design is applicable to any analyte for which there is a paper Palmes’ tube method, e.g. H2S, OCS, NO, SO2, O3, organic acids, NH3 and so on. As an example, the sampler for the determination of ambient atmospheric nitrogen dioxide (NO2), employing a trapping filter impregnated with triethanolamine is described. Performance of the new sampler was evaluated in laboratory and field experiments. The sampling rate was measured directly at four kerb-side sites in Oxford, UK and Kanagawa, Japan, by comparing measured concentrations from the samplers with co-located automated NO2 analyzers. Results showed mass transfer rate of NO2 within the diffuser did not change with external wind speed (0.5–2 m s−1). The passive device had relatively higher sampling rate than those of previous samplers and gave equivalent results on NO2 concentrations to the automated NO2 analyzer at 24 h or less sampling duration. LOD and LOQ indicated possible application of these devices to sampling in urban intermediate, urban background and suburban areas.