PhD position in atmospheric chemistry & physics
Atmospheric aerosols: probing how phase behavior of organic aerosols affects their ability to take up water and form clouds
Research area and project description:
Atmospheric aerosols are nano- to micro-meter sized particles suspended in the air and are key drivers for atmospheric chemistry, air pollution and climate. An important type of atmospheric particles is secondary organic aerosol (SOA). SOA particles mostly form within the atmosphere from oxidation reactions of organic precursor gases, followed by gas-to-particle conversion of the reaction products.
SOA particles are critical for climate via so-called aerosol-cloud interactions, where the aerosols can serve as nuclei for the formation of cloud droplets and ice crystals in clouds. Clouds, that on average cover 71% of the sky, are a key component of Earth’ energy budget, and hence climate system, due to their interaction with radiation in the atmosphere.
The ability of SOA particles to form clouds depends on their chemical and physical properties. A key property of SOA particles is their phase behavior, describing the number and types of phases in individual aerosol particles. Yet, the phase behavior of SOA is complex, and its impact on the ability of the particles to form clouds remains incomplete. As an example, in response to changes in atmospheric conditions, the phase type of SOA particles can change from a liquid to a semi-solid or solid phase state. Similarly, SOA particles can undergo phase transitions, such as liquid-liquid phase separation, all of which can affect their ability to take up water and form different types of clouds.
Establishing a fundamental understanding of these processes is an important challenge in atmospheric sciences, and the goal of this project.
Project goals & approach:
We are looking for a curious and motivated PhD student, to join our team and explore the phase behavior of SOA particles and assess how this affects their ability to take up water and form clouds.
Different SOA types will be generated in our atmospheric simulation chamber (AURA), from oxidation of different gas precursors. We will use microscopy-based techniques to study the phase behavior of these SOA particles, and use and further develop a range of advanced instrumentation to determine their ability to take up water and to form different types of clouds.
This experimental PhD project will be hosted at the Aerosol and Cloud Microphysics group lead by Asst. Prof. Fabian Mahrt, part of the Center for Chemistry of Clouds (C3), at Aarhus University. C3 comprises different research groups at the Department of Chemistry and provides an inclusive, collaborative and interdisciplinary environment to carry out the envisioned research, using leading experimental facilities for physical and atmospheric chemistry. This project will also benefit from ongoing collaboration with other research groups at C3 and beyond.
The PhD project is expected to be completed within 3 years for candidates who already have a MSc degree (5+3 degree structure) or 4 years for candidates who are currently enrolled in a MSc degree that has not been completed prior to the start of the PhD project (4+4 degree structure). The position is available from 01.02.2026 or as soon as possible thereafter. Asst. Prof. Fabian Mahrt will be the direct supervisor and Prof. Merete Bilde will be the formal supervisor.
Qualifications and specific competences:
Applicants to the PhD position must have finished a Master’s degree, or a Bachelor´s degree plus one year of completed Master´s studies, within Chemistry, Physics, Atmospheric Science or Nanoscience.
See website for Graduate School of Natural Sciences for more details on 5+3 vs. 4+4 PhD degree structures: phd.nat.au.dk/for-applicants/phd-study-structure-and-income
The successful candidate has demonstrated excellent academic results and works result-oriented with attention to detail. A strong interest atmospheric processes and in carrying out laboratory experiments and developing experimental setups is required. Prior experience with instrumentation to probe aerosols and clouds is an advantage.
The candidate must have good collaboration skills, be committed to integrate into a driving and collaborative environment, and at the same time be able to take responsibility and work independently on their project.
Place of employment and place of work:
The place of employment is Aarhus University, and the place of work is Aarhus University, Department of Chemistry, Langelandsgade 140, 8000 Aarhus C, Denmark.
How to apply:
For information about application requirements and mandatory attachments, please see the Application guide. Please read the Application guide thoroughly before applying.
When ready to apply, go to https://phd.nat.au.dk/for-applicants/apply-here/ (Note, the online application system opens 1 June 2025)
- Choose November 2025 Call with deadline 1 November 2025 at 23:59 CET.
- You will be directed to the call and must choose the programme “Chemistry”.
- In the boxed named “Study”: In the dropdown menu, please choose: “Readvertisement: Atmospheric aerosols: probing how phase behavior of organic aerosols affects their ability to take up water and form clouds (RAaphp)”
Please note:
- The programme committee may request further information or invite the applicant to attend an interview.
At the Faculty of Natural Science at Aarhus University, we strive to support our scientific staff in their career development. We focus on competency development and career clarification and want to make your opportunities transparent. On our website, you can find information on all types of scientific positions, as well as the entry criteria we use when assessing candidates. You can also read more about how we can assist you in your career planning and development.
Aarhus University’s ambition is to be an attractive and inspiring workplace for all and to foster a culture in which each individual has opportunities to thrive, achieve and develop. We view equality and diversity as assets, and we welcome all applicants. All interested candidates are encouraged to apply, regardless of their personal background.
See full details here: https://phd.nat.au.dk/for-applicants/open-calls/november-2025/readvertisement-atmospheric-aerosols-probing-how-phase-behavior-of-organic-aerosols-affects-their-ability-to-take-up-water-and-form-clouds