Facility for production of ambient-like model aerosols (PALMA) in the laboratory: application in the intercomparison of automated PM monitors with the reference gravimetric method

Abstract

Abstract. A new facility has been developed which allows for a stable and reproducible production of ambient-like model aerosols (PALMA) in the laboratory. The set-up consists of multiple aerosol generators, a custom-made flow tube homogeniser, isokinetic sampling probes, and a system to control aerosol temperature and humidity. Model aerosols containing elemental carbon, secondary organic matter from the ozonolysis of α-pinene, inorganic salts such as ammonium sulfate and ammonium nitrate, mineral dust particles, and water were generated under different environmental conditions and at different number and mass concentrations. The aerosol physical and chemical properties were characterised with an array of experimental methods, including scanning mobility particle sizing, ion chromatography, total reflection X-ray fluorescence spectroscopy and thermo-optical analysis. The facility is very versatile and can find applications in the calibration and performance characterisation of aerosol instruments monitoring ambient air. In this study, we performed, as proof of concept, an intercomparison of three different commercial PM (particulate matter) monitors (TEOM 1405, DustTrak DRX 8533 and Fidas Frog) with the gravimetric reference method under three simulated environmental scenarios. The results are presented and compared to previous field studies. We believe that the laboratory-based method for simulating ambient aerosols presented here could provide in the future a useful alternative to time-consuming and expensive field campaigns, which are often required for instrument certification and calibration.

2023 atomic spectrometry update – a review of advances in X-ray fluorescence spectrometry and its special applications

“…The TXRF spectrometry technique can be considered a potent competitor to ICP-MS in time-resolved size-segregated elemental analysis of airborne particulate matter . It was shown 51 to be more powerful than the conventionally used ICP-MS approach for samples collected on cascade impactors at high frequency. A major challenge, however, is traceable calibration based on RMs.…”

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“…The development of a facility producing multi-component model aerosols for instrument and procedure calibration would be a major step forward to improve significantly the accuracy of aerosol characterisation. Horender et al 47 introduced a novel facility for the production of ambient-like model aerosols in the laboratory. The concentrations of the model aerosols could be adjusted from a few μg m −3 to ca.…”

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“…A new prototype particle generator with a novel premixed-flame mode generated 27 such particles with an EC/TC ratio of 0.85 and mobility diameter of 50 nm without recourse to a thermal after-treatment process that had previously been required for generation using a diffusion flame. A new laboratory-based facility 28 for producing particles that mimic those found in ambient air employed: a generator for production of a carbonaceous particle fraction; a smog chamber to coat these particles with organic compounds and thereby simulate aged particles; a nebuliser to produce an inorganic-salt-particle fraction; and a rotating brush generator to produce a mineral-dust-particle fraction. It is anticipated that this facility will be used for: performance testing of new air sensors; measurement intercomparison studies; and health-related aerosol studies.…”