Profile
Marie Skłodowska–Curie Actions (MSCA) Fellow and Associated CERN Member with a PhD in Energy, Environment and Atmospheric Sciences. My research investigates how anthropogenic ammonia (NH₃) emissions influence upper-tropospheric aerosol formation and climate. I use the EMAC Earth system model, integrating mechanisms from the CLOUD experiment at CERN. I have been an Associated CERN Member (2023–2026) through the CLOUD experiment and have completed secondments at the Max Planck Institute for Chemistry (MPIC) and Airmodus. I publish in high-impact journals including PNAS and Nature, and I have served as a reviewer for Environmental Science & Technology. My work involves robust programming, data analysis, and high-performance computing.
Education
The Cyprus Institute
Research Project: Anthropogenic NH₃ in the Upper Troposphere: Impacts on Global Particle Formation and the Asian Tropopause Aerosol Layer
Supervisors: Associated Prof. Theodoros Christoudias and Prof. Jos Lelieveld
University College London
Degree Classification: Distinction
Research Project: Simulating the performances of ARIEL and JWST in probing the atmospheres of planets in the radius gap
Supervisors: Assistant Prof. Quentin Changeat and Prof. Ingo Waldmann
Imperial College London
Degree Classification: Distinction
Research Project: Inertial stability and the behaviour of tropical cyclones
Supervisor: Prof. Ralf Toumi
Imperial College London
Degree Classification: Upper Second Class Honours
Research Project: Sonoluminescence – Generating light from acoustically-driven bubbles
Supervisor: Prof. Roland A. Smith
The English School, Nicosia, Cyprus
A Levels: Physics (A*), Mathematics (A*), Further Mathematics (A*), Biology (A), Modern Greek (A)
IGCSEs: 6A*, 1A, 2B
Research Achievements & Peer Recognition
Summary of Research
I quantify the global impact of anthropogenic NH₃ on new particle formation (NPF) in the upper troposphere, where aerosols shape cloud properties and climate. Using Earth system modelling and CLOUD-derived NPF mechanisms, I show that NH₃—transported by convection from agricultural sources—enhances aerosol formation through interactions with sulfuric and nitric acids.
Simulations reveal that anthropogenic NH₃ increases cloud-forming particle concentrations by up to 2.5× over high-emission regions and raises aerosol optical depth by as much as 80%, amplifying climate effects. This work advances NH₃-driven NPF representation in global models, improving climate projections and informing policy.
Awards & Recognition
- Marie Skłodowska–Curie Actions (MSCA) CLOUD-DOC Fellowship (EU-2023).
- Ogden Prize: Awarded annually to one student for outstanding achievement in the Communicating Physics course (Imperial College London, 2019).
- As a result of the Ogden Prize, my name was written into the memory of the magnetometer instrument of the Solar Orbiter spacecraft (Imperial College London, 2019).
Publications
- Christos Xenofontos et al. “Global impact of anthropogenic NH₃ emissions on upper tropospheric aerosol formation.” Proceedings of the National Academy of Sciences 122.44 (2025): e2506658122.
- Christos Xenofontos et al. “The impact of ammonia on particle formation in the Asian Tropopause Aerosol Layer.” npj Climate and Atmospheric Science 7.1 (2024): 215.
- Douglas M. Russell et al. “Isoprene chemistry under upper-tropospheric conditions.” Nature Communications 16.1 (2025): 8555.
- Nirvan Bhattacharyya et al. “Isoprene aerosol growth in the upper troposphere: application of the Diagonal Volatility Basis Set to cloud chamber measurements.” ACS ES&T Air 2.10 (2025): 2092–2104.
- Jiali Shen et al. “New particle formation from isoprene under upper-tropospheric conditions.” Nature 636.8041 (2024): 115–123.
Academic & Professional Engagements
Secondments
-
CERN CLOUD experiment, Geneva, Switzerland (2023–2026)
Supported experimental campaigns through night shifts and contributed to planning discussions. -
Airmodus Ltd., Helsinki, Finland (2024)
Three-week secondment to enhance the Airmodus PSM inversion tool in Python, improving user-interface clarity, implementing error/uncertainty metrics, and refining data visualization. -
Max Planck Institute for Chemistry, Mainz, Germany (2023)
Two-month collaboration developing the EMAC model setup for simulating atmospheric particle formation and evaluating its climate impact.
Conferences
- COMECAP, Nicosia, Cyprus (2025) – Oral: Impact of anthropogenic NH₃ on UT aerosol.
- ICNAA, Vienna, Austria (2025) – Oral: Impact of anthropogenic NH₃ on UT aerosol. Served as Session Chair.
- EGU General Assembly, Vienna, Austria (2025) – Oral: Anthropogenic NH₃ impact on UT aerosol composition and climate forcing.
- EAC, Tampere, Finland (2024) – Oral: Impact of NH₃ on particle formation in the Asian Tropopause Aerosol Layer.
- EGU General Assembly, Vienna, Austria (2024) – Poster: Modelling the impact of NH₃ emissions on NPF in the Asian Monsoon UT.
Schools
- Participant at the second CLOUD-DOC Summer School in Finland (2024)
- First CLOUD-DOC Summer School in Frankfurt (2023)
- EMME-CARE Autumn School on “Analysis of aerosols, air pollution and their sources in the Eastern Mediterranean” in Cyprus (2022)
- 1st MedCyclones Workshop and Training School at the University of Athens, COST Action CA19109 MedCyclones (2022)
Positions of Responsibility
The Cyprus Institute
- Represented student interests at the Graduate School level in academic and institutional decision-making.
- Organized student-led events, fostering academic engagement and community-building.
- Supported student well-being and productivity through peer outreach and feedback mechanisms.
- Acted as liaison between students and faculty, ensuring transparent communication and leadership representation.
CLOUD Collaboration
- Reviewed and provided feedback on student paper drafts to uphold scientific clarity.
- Ensured accuracy of author lists, affiliations and acknowledgements across CLOUD publications.
- Represented doctoral students in discussions with senior researchers on publication planning and policy.
Chelsea Academy
- Delivered weekly physics instruction to secondary-level students over one academic term.
- Mentored final-year students achieving gold and silver medals in Physics Olympiads.
Skills
Languages
- Greek (native)
- English (native)
- French (IGCSE)
Programming & Modelling
- Python
- Fortran
- SQL
- Earth system model development (EMAC)
- HPC environments
- Unix/Linux
Software & Tools
- Microsoft Office (Word, Excel, PowerPoint)
- Git
- LaTeX
Additional Certifications
- Python Programming – Coursera & Python Institute Certified.
- Experience with large-scale simulations, data analysis and collaborative research workflows.
- Certificate of very good knowledge of the Greek language (Ministry of Education, Republic of Cyprus, 2015).
- Duke of Edinburgh Bronze and Silver awards.
- Taekwondo 8 Kup-Promotion Test Participant (Taekwondo World Federation).
- Participant at the 23rd Cyprus Mathematical School organised by the Cyprus Mathematics Society.
Press/Media
- PNAS news on X (formerly Twitter) in 2025
- PNAS news on Bluesky (2025)
- PNAS news on LinkedIn (2025)
- World News (WN) in 2025
- AZoCleantech (2025)
- MSN (2025)
- Kudos (2025)
- EMME-CARE (2025)
- EMME-CARE (2024)
- PSI (2025)
- Max Planck Institute for Chemistry (2025)
- Ant1 Live (2025)
- Phileleftheros (2025)
- CNA (2025)
- Stockwatch (YgeiaWatch) in 2025
- Springer Nature (Research Communities) in 2024