Chemical Characterization of Atmospheric Ultrafine Particles

Objectives

  • Development of a method for the chemical characterization of ultrafine atmospheric particles
  • Comparison of single particle and ensemble techniques

Method of Approach

  • Collection of atmospheric particles by size resolved impaction
  • Analysis of the adsorbed particles by:
    • Laser Desorption-SICRIT-MS (LD-SICRIT-MS)
    • Thermal Desorption-SICRIT-MS (TD-SICRIT-MS)
    • Scanning Electron Microscopy with Energydispersive X-Ray-Spectroscopy (SEM-EDX)
    • Atomic Force Microscope Infrared-Spectroscopy (AFM-IR)

Description

Ultrafine particles (UFP) are known to impact health and the climate, yet no field-applicable method for daily monitoring of atmospheric UFPs exists. In our project on the chemical characterization of atmopheric ultrafine particles, we collect particles by size resolved impaction and compare different methods for their analysis. So far, LD-SICRIT-MS, TD-SICRIT-MS, SEM-EDX and AFM-IR have been employed. A promising approach for daily monitoring was found with TD-SICRIT-MS (shown in the figure), for which the HELIOS (high efficient light source for optical surface desorption), an IR-based desorption device previously developed within the group is used.  The applicability of this method for the investigation of different substance classes was shown and a detection capability in the range of nanograms was found with pyrene as a test substance. Measurements of the collected particles with subsequent cluster analysis showed a similarity of the chemical composition of neighboring impaction stages and therefore within a size range. SEM-EDX measurements showed a shift in the composition of the collected particles from mainly carbonaceous species to inorganic species with increasing size.

Financial Support and Cooperation Partner

Bayerisches Landesamt für Umwelt (LfU)