Laboratory and field testing of new design nitrogen dioxide diffusive samplers

Abstract

Nitrogen dioxide is one of the most monitored pollutants in ambient air because of this effect on the human respiratory system, his contributions to the acidification of the ecosystems and his role in the formation of photochemical oxidants. The level of nitrogen dioxide in rural and suburban areas is governed by imported air-pollution, and elevated NO2 concentrations due to local traffic and increased industrial activity. The passive diffusive samplers have been used for many years to measure outdoor concentrations of nitrogen dioxide (NO2) across rural and urban area. Passive sampling is based on the principle of passive diffusive of a pollutant through an air layer to an absorbing medium. The mean concentration of pollutant is calculated from the collected amount integrated over the sampling time. Neither pumping of air nor electricity is needed in passive sampling. The present study is directed to investigate new design diffusive samplers impregnated with 10 % and 20 % triethanolamine (TEA) solution diluted with water. Investigation was carried out in laboratory chamber and under field conditions. During investigation was obtained good agreement with chemiluminescence measurements (correlation coeficient r = 0.99) or control diffusive samplers (r = 0.94). Results indicate that the accuracy of this device when compared to co-located continuous NOx analyzer during chamber research is 10 % with precision of 8 % (relative standard deviation). However during field testing new diffusive samplers showed less accuracy 23 % and worse precision 12 %. But nevertheless, the new device complies with the Directive 2008/50/EC requirement for uncertainty (precision and bias) < 25 %.