Laboratory development and field evaluation of a new diffusive sampler to collect nitrogen oxides in the ambient air

Abstract

Diffusive samplers for the determination of NO(x) and NO2 based on collection on a coated carbon paper filter have been developed. NO is first oxidized to NO2 and then collected on the reactive surface. When NO2 and NOx samplers are exposed simultaneously, NO can be calculated by difference. The sampler has been derived from a Palmes design as recently modified by Bertoni et al. for the determination of BTX (benzene, toluene, xylenes). Laboratory tests were conducted in controlled atmosphere to evaluate linearity, uptake rate, face velocity effects, sample stability, influence of relative humidity, precision and accuracy. The samplers are capable of reliable measurements of the two species at common levels of a polluted atmosphere in urban settings yielding average concentration levels over 1 month and beyond. The uptake rate of NO2 was found to be 11.7 mL/min in a very good agreement (within 5%) with the value calculated from theory. The measured uptake rate for NO(x) was determined in experiments involving sampling at different concentration levels in comparison to chemiluminescence (CL) measurements. The precision of the measurements for co-located passive samplers was better than 5%. The accuracy of the data collected is within +/-20% of the actual value measured by CL. The laboratory and field results show that the NO(x) and NO2 samplers meet the data quality goal requested by the first EU Directive 1999/30/EU for these pollutants.

Representativeness of Urban Highest Polluted Zones for Sitting Traffic-Oriented Air Monitoring Stations in a Chinese City

“…Since the development and use of the Analyst® has been fully described in previous (6) publications of this laboratory (7), (8) no further information are here reported. Sampling was carried out by mounting the Analyst® samplers at heights of approximately 2.5 meters above ground level under a protective shelter with their open ends down to exclude dust, rain-sheltered, airy, beyond the kerbside.…”

“…For the organic samples 300 gaschromatographic analyses were done and for the inorganic samples (SO 2 , NO x , O 3 , NH 3 ) 1 020 ionic chromatographic analyses. Comparison between Analyst diffusive sampling technique and automatic reference methods has been already done (7), (8) and not studied in this work.…”

Simultaneous measurement of nitrous acid, nitric acid, and nitrogen dioxide by means of a novel multipollutant diffusive sampler in libraries and archives

“…The body of the multipollutant diffusive sampler is similar to the Analyst [27]. The internal design of the sampler, on the other hand, was changed to collect HNO 3 , on the first filter and NO 2 and HONO in the successive absorbing pads.…”

“…Filters are placed along the diffusive path in front of the alkaline carbon filter prepared according to the procedure already described [27] and positioned at the bottom of the device for the sole NO 2 sampling. An enlarged scheme of the sampler is reported in Fig.…”

“…As for the other diffusive samplers, the multipollutant samplers at the end of collection time were sealed and successively analysed according to a procedure similar to the one reported elsewhere for NO 2 [27]. In this case the filters were removed from the sampler, then they were extracted by adding a solution of sodium bicarbonate and carbonate, 0.3 mM NaHCO 3 and 2.7 mM Na 2 CO 3 in a plastic vial.…”