title: NO(2) measurement artifacts in the presence of soot.
abstract: Nitrogen dioxide is a regulated pollutant, which is measured routinely. Since it can be formed during combustion processes, it is often measured in the presence of soot. This study investigates the possible artifact formation due to the interaction of soot and NO2 in the sampling lines and instrument prefilters. The transfer of varying NO2 concentrations through filters and tubes coated with different kinds of soot was investigated by using a dedicated photoacoustic soot and NO2 analyzer (TwinPAS). The effects of flow rate, temperature, relative humidity, tubing respectively filter material, soot reactivity, and passivation on the NO2 measurement artifacts have been investigated. We found significant lags (up to 2 min) of the NO2 transfer as well as total NO2 losses of up 10 %.
authors.affiliation: Institute for Hydrochemistry, Chair of Analytical Chemistry, Technische Universität München, Marchioninistr, 17, 81377, Munich, Germany.
authors.forename: Jan-Christoph
authors.initials: JC
authors.lastname: Wolf
authors.forename: Alexander
authors.initials: A
authors.lastname: Danner
authors.forename: Reinhard
authors.initials: R
authors.lastname: Niessner
authors.forename: Christoph
authors.initials: C
authors.lastname: Haisch