Annular diffusion denuder for simultaneous removal of gaseous organic compounds and air oxidants during sampling of carbonaceous aerosols

作者：Mikuska Pavel^*; Vecera Zbynek; Bartosikova Anna; Maenhaut Willy

来源：Analytica Chimica Acta, 2012, 714: 68-75.

DOI：10.1016/j.aca.2011.11.054

• Annular diffusion denuder
• Organic compounds
• Oxidants
• Carbonaceous aerosols
• Sampling artefacts

A specially designed annular diffusion denuder for simultaneous removal of organic gaseous compounds and atmospheric oxidants in carbonaceous aerosol sampling is presented. Various kinds of denuder coatings were compared with respect to the collection efficiency of both organic gaseous compounds and NO2 and ozone. The optimum sorbent is a mixture of activated charcoal and sulfite on molecular sieve. To ensure high collection efficiency over long-term field operation, two annular diffusion denuders are combined in series. The first half of the first denuder is filled with Na2SO3 on molecular sieve (23 cm long layer) while the second half of the first denuder and the whole second denuder are filled with activated charcoal (the total length of the charcoal section is 67 cm). %26lt;br%26gt;At a flow rate of 16.6 L min(-1), the collection efficiency of organic gaseous compounds and atmospheric oxidants in the annular diffusion denuder is better than 95%. Only small losses of aerosol particles (%26lt;3.6% in number concentration) were observed in the size range 0.12-2.26 mu m. %26lt;br%26gt;The annular diffusion denuder is compatible with the collection of aerosols on 47-mm diameter quartz fiber filters at a flow rate of 16.6 L min-1. The use of this denuder enables one to sample carbonaceous aerosols on filters without positive sampling artefacts from volatile organic compounds and interferences from atmospheric oxidants. The annular diffusion denuder has been applied successfully for the sampling of carbonaceous aerosols during field campaigns of typically 1 month each at urban and forested sites in Europe.

• 出版日期2012-2-10