Wednesday, 22 May 2002
Field evaluation of passive samplers and deposition velocity for NO2
Atmospheric NO2 has been linked to various detrimental effects on ecosystems and human health including acidification, nitrogen loading, and ground level ozone. Current research estimates that NO2 dry deposition accounts for approximately half of the total NO2 deposition to the environment. At present, there is no continuous monitoring network established in Canada to assess the concentrations and dry deposition of NO2. In 2001, a study was initiated over a rural grassland at the Elora Research Station (43o9’N 80o25’W, 376 m elev.), Ontario, Canada, to evaluate the most cost effective and accurate passive method of measuring atmospheric concentrations of NO2. Four passive samplers, Maxxam’s PASS, Gradko’s Palmes Tube, CSIRO’s Badge sampler, and the Ogawa sampler were simultaneously exposed for repeated 3 and 6 day periods over the summer of 2001 and compared to two chemiluminescence analysers which were used as a reference. In conjunction with this study, the fluxes and deposition velocities for NO2 were determined using the flux gradient method and two chemiluminence analysers sampling at 30 second intervals from two heights of 0.3 and 0.5 m. Results on the performance of the samplers will be presented along with the various fluxes and deposition velocities of NO2 over a rural grassland.
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