Quantification of Low Pressure Impactor Wall Deposits during Zinc Nanoparticle Sampling

Abstract

A Dekati® low pressure impactor (DLPI) is used to determine the mass distribution of airborne particles from 7 nm to 10 µm as a function of aerodynamic diameter. Quantification of wall deposits inside this sampling device was performed for the first time using polydisperse zinc aerosol produced by a thermal spraying process. This aerosol is more representative of the size distribution found in occupational atmospheres than aerosols usually produced in laboratories. Each experiment (3 replicates) was carried out for two durations. The results showed that wall deposits were quite considerable and in relation with aerosol modes. 13% and 14% of the total mass was found on the wall after sampling periods of 5 and 20 minutes, respectively. Relative losses could reach 50% for certain impaction stages and these losses were also quite different between replicates.

Secondary organic aerosol formation from OH-initiated oxidation of <i>m</i>-xylene: effects of relative humidity on yield and chemical composition

“…The self-and cross-reactions of RO 2 radicals also form ROOR (C 16 H 22 O 10 ) or ROOR', which are the accretion products (Berndt et al, 2018;Molteni et al, 2018). The further O 2 adduct of BPR can form highly oxygenated RO 2 radicals and further react and finally form highly oxygenated organic molecules (HOMs; Types 1 and 2 in Scheme 1; Wang et al, 2017;Crounse et al, 2013;Ehn et al, 2014;Jokinen et al, 2015;Berndt et al, 2016). Dimethylphenol (C 8 H 10 O) and other products from the termination reaction with the benzene ring or double bond can react with OH radicals and further react to form HOMs as well.…”

Inertial Impaction Technique for the Classification of Particulate Matters and Nanoparticles: A Review

“…et al, 2013b). In another study, 80 % of particle loss was found to concentrate around the nozzles and 20 % on the impaction plate in a stage of the DLPI (Dekati ® Low-Pressure Impactor) (Durand T. et al, 2014).…”

“…Experimental and theoretical studies have been conducted for determining the particle losses by impaction and diffusion (Chen S.C. et al, 2007). The inertial loss of large particles normally occurs on the contractions which connect the big inlet tube to the small nozzle or on the surface of nozzle plate (Durand T. et al, 2014;Gupta T., 2015a, 2015b).…”

“…Some commonly used cascade impactors are Andersen cascade impactor (Andersen A.A., 1966), Mer-cer cascade impactor (Mercer T.T. et al, 1970), Quartz Crystal Microbalance (QCM) cascade impactor (Hering S.V., 1987), Pilat cascade impactor (Pilat M.J. et al, 1970), Berner low-pressure cascade impactor (Berner A., 1972), Low-Pressure Impactor (Berner A., 1972), Dekati ® Low-Pressure Impactor (DLPI) (Durand T. et al, 2014), MOUDI (Marple V.A. et al, 1991;Marple V.A.…”

“…But several limitations are inherent to the impactors such as particle bounce and re-entrainment (Turner J.R. and Hering S.V., 1987;Fujitani Y. et al, 2006), particle overloading (Tsai C.J. and Cheng Y.H., 1995;Demokritou P. et al, 2004b), and particle loss (Fang C. et al, 1991;Durand T. et al, 2014), which can degrade their performance. Moreover, some typical characteristics of the inertial impactors such as the cutoff diameter, the sharpness of collection efficiency curve, and the properties of the impaction substrate should be understood well since PMs have different sizes, shapes, types, compositions and characteristics (Loo B.W., 1975;Hinds W.C., 1999).…”