Annular denuder method for sampling reactive gases and aerosols in the atmosphere

Comparison of NO2 and SO2 Measurements Using Different Passive Samplers in Tropical Environment

“…In fact, a series of experiments with the ADS in the same environmental conditions have shown that the collection of NO 2 on a coating prepared from a mixture of components as mentioned above was quite consistent and comparable (De Santis et al, 1996). In addition, it has been reported that the collection efficiency (E) of coating solution (Na 2 CO 3 -glycerine in water/methanol) for acidic gases including NO 2 and SO 2 could be up to 98% (Allegrini et al, 1987), for which the definition of E would be discussed later.…”

Chemical characteristics of inorganic ammonium salts in PM<sub>2.5</sub> in the atmosphere of Beijing (China)

“…Ambient concentrations of gases and particles were measured using the annular denuder system (Possanzini et al, 1983;Allegrini et al, 1987;Febo et al, 1989;Perrino et al, 1990Perrino et al, , 2001Perrino and Gherardi, 1999;Beine et al, 2001, Ianniello et al, 2002. The denuder line configuration used in this study included two sodium fluoride (1 % NaF in 9:1 ethanol/water solution) coated denuders for the simultaneous collection of HCl and HNO 3 , followed by two sodium carbonate plus glycerol (1 % Na 2 CO 3 + 1 % glycerol in 1:1 ethanol/water solution) coated denuders for the collection of HONO and SO 2 .…”

Occurrence of gas phase ammonia in the area of Beijing (China)

“…Annular denuder techniques are considered to be able to overcome these critical sources of error. In general, such systems are designed with a vertically positioned denuder tube to eliminate the sedimentation of particles (Possanzini et al, 1983;Allegrini et al, 1987Allegrini et al, , 1999Febo et al, 1989;Perrino et al, 1990). This sampling technique is able to accurately determine gaseous ammonia and particulate ammonium without disturbing the partition existing in the atmosphere at the time of the sampling and without mutual interferent (Perrino et al, 1999(Perrino et al, , 2002.…”

“…Problems occurred on 9 February between 10:00 and 12:00 in the morning and on 19 August between 22:00 and 00:00, thus data from these events were not considered. The annular denuder sampling method and the analytical procedures were described in several past works (Possanzini et al, 1983;Allegrini et al, 1987Allegrini et al, , 1999Febo et al, 1989;Perrino et al, 1990Perrino et al, , 2001aBeine et al, 2001;Ianniello et al, 2002). After collection, the denuders and filters were extracted and samples were analyzed within 24-h by using Ion Chromatography (IC) (Dionex DX 120 connected with autosampler DX AS50 for anions and DX ICS90 connected with autosampler DX AS40 for cations).…”