MaSMob-Lion · Mass-Mobility-Size for light ions/clusters
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2021-08-01 → 2023-08-31
- EU contribution
- €160,616
- Participants
- 2
- Scheme
- MSCA-IF
Lines connect the coordinator with its partners.
Results in brief
Mass-Mobility-Size for light ions/clusters
The MaSMob-Lion project investigates the mass, size, and electrical mobility relation of light ions and clusters in gas. By measuring experimentally the mobility and mass of ions with known structures using a Planar Differential Mobility Analyser coupled with a Time-of-Flight Mass Spectrometer (DMA-MS, Figure 1), high quality data are collected in nitrogen and air under different temperature and humidity conditions. These data provide insights in studying how ion mobility respond to temperature and humidity changes as well as to carrier gas and ion conformation. Through the effective diameter approach, the measured mass-mobility relation is further linked to ion size in the free molecular regime. The derived parameters are comparable to the derivation using coefficients suggested in the ISO15900. The temperature, humidity and structure dependence of the mass-mobility relation is parameterised. However, due to possible solvation/oxidation in dry conditions and limitation in the generalisation of the parameterisations, a reliable model cannot be formulated yet. Further experiments with ions of more diverse functional groups and structures are necessary to be carried out with better control over the ionisation, especially in dry conditions. In addition, this project also explores how particle activation diameter measured by supersaturation-based instruments, e.g. a Particle Size Magnifier (PSM), is related to the ion mass and mobility. The experimental results suggest that for monomer ions, the initial diethylene glycol (DEG) attachment is likely site dependent, and water assists in this process. Although the project has ended officially on August 31, 2023, further investigations on the initial DEG attachment and the role of water are continued in collaboration with modellers. In general, the overall outcomes of the project meet the objectives, in spite of delays and technical difficulties. The work carried out in the project points at the necessities of improvement in future experimental design and provides a means towards the formulation of a model for mass-mobility-size conversion.
Data: CORDIS, © European Union
Project objective
Atmospheric new particle formation adds large spatial and temporal variations to the number size distributions of atmospheric aerosol particles, which brings great complexity in evaluating their health and climatic impacts. It is therefore crucial to understand the formation of atmospheric new particles from gas phase and their subsequent growth at a fundamental level. This solution however is obscured by the over-simplified theory in describing the free-molecular mass-mobility-size relationship. The MaSMob-Lion project is proposed to refine the theoretical basis of the mass-mobility-size relationship to improve its accuracy and reliability in describing the initial particle formation from gas phase. In MaSMob-Lion, the ER will focus on the carrier gas polarizability and conformation effects of <10 nm particles. These effects on mass-mobility relation will be probed experimentally with isomeric monomers and multimers in different carrier gases using the tandem mass-mobility setup and their linkage to particle size will be rationalised through the effective diameter approach with correction terms. Especially, the ER attempts to extend the parameterisations down to the sub-1 nm range for a consistent mass-mobility-size system capable of describing the gas-to-particle phase transition and the subsequent growth. These new knowledges will be used in formulating an easily implementable simple model to assist a quick conversion between mass, mobility and size. Aerosol particles can be measured by their mass and mobility. But in addition, sub-3 nm particles can also be studied via a growth-based method in a supersaturated condensable vapour. The ER will also conduct alternative and complementary mass-mobility study through supersaturation. While aiming to obtain a holistic picture on the mass-mobility-size relationship that can be used to compare different measurement techniques, these additional data will also be used in model validation and refinement.
Original text from CORDIS.
Participants
- TARTU ULIKOOL · TartuCoordinatorEstonia
- THE TRUSTEES OF INDIANA UNIVERSITY · BloomingtonUnited States
Links
Data: CORDIS, © European Union