Referenz-Russpartikel mit organischen und inorganischen Substanzen

• Research unit: METAS
• Project number: F-5235.30161

Key words (English)

atmospheric particles, soot aerosols, secondary organic matter, ammonium sulphate, aerosols, miniCAST soot generator

Short description (English)

As part of the AeroTox project, METAS has characterized a new photo-oxidation reactor that produces secondary organic matter (SOM). With the "miniCAST photo-oxidation reactor" setup, we were able to coat soot particles with SOM and thus generate a series of reference aerosols for health studies and for the calibration of BC photometers. However, we know that soot particles in the atmosphere are not only internally mixed with organic species but also simultaneously with inorganic species.

Project aims (English)

With this small-scale project we want to go one step further by mixing inorganic substances such as ammonium sulphate into the coated soot particles. The salt particles are generated with a vervebler. The particle size distribution is measured with SMPS and the particle morphology is examined with transmission electron microscopy (TEM). If the small-scale project is successfully completed, the aerosol generation system of the PALMA plant will be replicated accordingly. 

Abstract (English)

As part of the small-scale project ""Reference carbon black particles with organic and inorganic substances"", we were able to show that it is possible to mix inorganic substances, such as ammonium sulphate, with carbon black particles, and subsequently with secondary organic material (SOM) using a photo-oxidation reactor. 
Transmission electron microscopy (TEM) images of the particles showed that approx. 50 % of the generated aerosols are homogeneously/internally mixed. This allowed us to produce reference aerosols as they occur in the atmosphere and not solely heterogeneous mixtures of soot, coated soot or inorganic substances. 

Transfer and application (English)

The results were presented at the IAC2022 in Athens. 
The results of the small-scale project also provide a valuable basis for the EPM StanBC project, which started in June 2023. In addition, the reference aerosols generated can also be used for health studies and for the calibration of BC photometers (e.g. as part of the StanBC project). At the moment, the photo-oxidation reactor is being used for measurements at the MAXIV particle accelerator in Lund (Sweden) to analyze salt particles coated with SOM. Furthermore, exposure studies with SOM-coated soot aerosols were carried out, also in Lund. This enabled METAS to expand and intensify its network with other European aerosol research groups. When the photo-oxidation reactor is back at METAS, the PALMA facility with the photo-oxidation reactor will be retrofitted accordingly.

Publications / Results (English)

The results were presented at the IAC2022 in Athens.