About Me

My name is Ursula Jongebloed (pronounced "youngblood") and I am an atmospheric chemist interested in aerosols and their impacts on climate. My work synthesizes knowledge across multiple earth science disciplines, including isotope geochemistry, atmospheric chemistry, paleoclimatology, volcanology, and climate science to understand how aerosols influence and are influenced by the earth system.

I am currently an MIT School of Science Dean's Postdoctoral Fellow hosted by Arlene Fiore (MIT EAPS) and Jesse Kroll (MIT CEE). During my PhD advised by Becky Alexander, I used ice cores and atmospheric chemistry modeling to understand sulfate aerosol sources and chemistry during the preindustrial and industrial eras. My PhD research can be broadly divided into three topics by source of sulfate aerosols: volcanoes, marine phytoplankton, and human activities.

Research

Fumarole on Mt. Hood in Oregon (picture taken by me)

Sulfate aerosols from passive volcanic degassing

Passive (i.e. non-eruptive) volcanic degassing is a significant and uncertain source of natural sulfate. We compare ice core volcanic sulfate concentrations to a global chemical transport model and have found that sulfur emissions from passive volcanic degassing are underestimated in global climate models. This is likely caused by the exlusion of hydrogen sulfide, a rotten-egg smelling gas that is emitted by hydrothermal vents and non-erupting volcanoes. This result has important implications for sulfate radiative forcing and the global sulfur budget.

Related publications: Jongebloed, U.A. et al. (2026) Southern ocean sulfate aerosol sources quantified from sulfur isotopes in Antarctic ice cores. Geophysical Research Letters, 53, e2025GL118622, https://doi.org/10.1029/2025GL118622; Jongebloed, et al. (2023), Underestimated passive volcanic sulfur degassing implies overestimated anthropogenic aerosol radiative forcing, Geophysical Research Letters, 50, e2022GL102061. https://doi.org/10.1029/2022GL102061

See news articles/podcasts about our 2023 GRL paper in NPR's Soundsize Podcast (minutes 5:35 to 16:39), Science Alert, New Scientist, Environmental News Network, UW News, and many others. According to Altmetric, the attention this paper received is in the top 1% of papers published around the same time and top 3% of papers published in GRL!

Marine phytoplankton sulfur emissions and chemistry

Marine phytoplankton are primary producers in ocean ecosystems and influence climate through emissions of a sulfur compound called dimethyl sulfide (DMS) to the atmosphere. We use sulfur isotopes to quantify how much sulfate comes from phytoplankton and compare it to methanesulfonic acid, a commonly used proxy for DMS emissions. We find that pollution-driven changes in atmospheric chemistry drove changes to DMS oxidation chemistry, influencing trends in both Greenland and Alaskan ice core MSA records. We use a chemical transport model to explore how key oxidation mechanisms capture ice core trends and in situ observations of DMS and oxidation products.

Related publications: Jongebloed, U.A. et al. (2025) Dimethyl sulfide chemistry over the industrial era: comparison of key oxidation mechanisms and long-term observations. ACP.https://doi.org/10.5194/acp-25-4083-2025; Chalif et al. (2024), Pollution drives multidecadal decline in subarctic methanesulfonic acid. Nature Geoscience. https://doi.org/10.1038/s41561-024-01543-w; Jongebloed et al. (2023), Industrial-era decline in Arctic methanesulfonic acid is offset by increased biogenic sulfate aerosol. Proceedings of the National Academy of Sciences, 120(47). https://doi.org/10.1073/pnas.2307587120

See a news articles about our PNAS paper in: UW News and about our Nature Geoscience paper in: Newsweek!

Marine phytoplankton in the Barents Sea (NASA Earth Observatory)

Anthropogenic sulfur dioxide emissions from a coal-fired power plant in Fairbanks, AK (picture by Yuk Chun Chan)

Anthropogenic and natural sulfate over industrial era

Anthropogenic activities such as fossil fuel burning have increased the abundance of sulfate aerosols to the atmosphere, which have partially offset the warming caused by human greenhouse gases. In recent work, we use a Greenland ice core to quantify how much sulfate comes from anthropogenic activities versus natural sources over the industrial era (Jongebloed et al., 2023 ERL). We also use sulfur and oxygen isotopes of sulfate aerosol samples to investigate pollution sources in Fairbanks, Alaska, which is one of the most polluted cities in the U.S. (Moon et al., 2023).

Related publications: Jongebloed et al. (2023), Quantifying the impact of anthropogenic sulfur emissions on industrial-era Arctic sulfate in a Greenland ice core. Environmental Research Letters. https://doi.org/10.1088/1748-9326/acdc3d; Moon, A.R., Jongebloed, U.A., Dingilian, K.K., Schauer, A.J., Chan, Y.C., Cesler-Maloney, M., et al. (2023). Primary Sulfate Is the Dominant Source of Particulate Sulfate during winter in Fairbanks, Alaska. ACS ES&T Air. https://doi.org/10.1021.acsestair.3c0023.

Publications

Also see Google Scholar

[11] Jongebloed, U. A., Fischer, T. P., Kyle, P. R., Kang, L., Alexander, B. (2026) Southern ocean sulfate aerosol sources quantified from sulfur isotopes in Antarctic ice cores. Geophysical Research Letters, 53, e2025GL118622. https://doi.org/10.1029/2025GL118622

[10] Jongebloed, U. A., Chalif, J. I., Tashmim, L., Porter, W. C., Bates, K. H., Chen, Q., Osterberg, E. C., Koffman, B. G., Cole-Dai, J., Winski, D. A., Ferris, D. G., Kreutz, K. J., Wake, C. P., and Alexander, B. (2025). Dimethyl sulfide chemistry over the industrial era: comparison key oxidation mechanisms and long-term observations. Atmospheric Chemistry and Physics, 25(7), 4083-4106https://doi.org/10.5194/acp-25-4083-2025

[9] Kang, L., Marchand, R., Ma, P.-L., Huang, M., Wood, R., Jongebloed, U. A., and Alexander, B. Impacts of DMS Emissions and Chemistry on E3SMv2 Simulated Cloud Droplet Numbers and Aerosol Concentrations Over the Southern Ocean. J. Advances in Modeling Earth Systems. https://doi.org/10.1029/2024MS004683

[8] Fredrickson, C. D., Janz, S. J., Lamsal, L. N., Jongebloed, U. A., Laughner, J., and Thornton, J. A. (2025). Remote Sensing Estimates of Time-Resolved HONO and NO2 Emission Rates and Lifetimes in Wildfires. Atmospheric Measurement Techniques. https://doi.org/10.5194/amt-18-3669-2025

[7] Chalif, J. I., Jongebloed, U. A., Osterberg, E. C., Koffman, B. G., Alexander, B., Winski, D. A. et al. (2024). Pollution drives multidecadal decline in subarctic methanesulfonic acid. Nature Geoscience.https://doi.org/10.1038/s41561-024-01543-w

[6] Chan, J., Parasurama, S., Atlas, R., Jongebloed, U. A., Alexander, B., Langenhan, J. M., Thornton, J. A., Riffell, J. A. (2024). Olfaction in the Anthropocene: NO3 negatively affects floral scent and nocturnal pollination. Science, 383(6683), 607-611. https://doi.org/10.1126/science.adi0858

[5] Moon, A., Jongebloed, U. A., Dingilian, K. K., Schauer, A. J., Chan, Y.-C., Cesler-Maloney, M., et al. Sulfur and Oxygen Isotopes Show Primary Sulfate is the Dominant Source of Particulate Sulfate During Winter in Fairbanks, AK, ACS ES&T Air. https://doi.org/10.1021/acsestair.3c00023

[4] Jongebloed, U. A., Schauer, A. J., Cole-Dai, J., Larrick, C. G., Porter, W. C., Tashmim, L., Salimi, S., Edouard, S. R., Geng, L., and Alexander, B. Industrial-era decline in Arctic methanesulfonic acid is offset by increased biogenic sulfate aerosol, Proceedings of the National Academy of Sciences, 120(47). https://doi.org/10.1073/pnas.2307587120

[3] Jongebloed, U. A., Schauer, A. J., Cole-Dai, J., Hattori, S., Larrick, C. G., Salimi, S., Edouard, S. R., Geng, L., and Alexander, B. Sulfur isotopes quantify the impact of anthropogenic activities on industrial-era Arctic sulfate in a Greenland ice core, Environmental Research Letters, https://doi.org/10.1088/1748-9326/acdc3d

[2] Jongebloed, U. A., Schauer, A. J., Cole-Dai, J., Larrick, C. G., Wood, R., Fischer, T. P., Carn, S. A., Salimi, S., Edouard, S. R., Zhai, S., Geng, L., Alexander, B. (2022) Underestimated passive volcanic sulfur degassing implied overestimated aerosol forcing. Geophysical Research Letters, 50, e2022GL102061. https://doi.org/10.1029/2022GL102061

[1] Review paper: Banerjee, A., Riddell-Young, B. E., and Jongebloed, U. A. (2022). Ice-core records of atmospheric composition and chemistry. Past Global Changes Magazine, 104-105, 30(2), https://doi.org/10.22498/pages.30.2.104

Outreach

Growing up as the daughter of a middle school teacher and granddaughter of three elementary school teachers, education and outreach has always been important to me. I have volunteered as the graduate student coordinator of the UW Atmos Outreach Program, served as a teaching assistant for two classes and lead teaching assistant for four academic quarters, acted as graduate student representative in the UW Program on Climate Change Graduate Steering Committee (see blog post for PCC Spring Symposium), mentored five undergraduate students, and served as a member of the UW Campus Sustainability Fund's program to encourage projects on intersectional sustainability. I also recently co-authored an article for Past Global Changes Magazine on ice-core records of atmospheric composition and chemistry, a review paper intended for a non-expert (e.g. undergraduate or high school) audience. Finally, I am serving as the lead graduate student organizer of the Ice Core Early Career Researcher Workshop 2023 (ICECReW lead organizer in 2023 and 2024, and co-organizer in 2025), which is a professional development workshop for early career researchers with the underlying goal of increasing the inclusivity and accessibility of ice core science.

CV

2025- MIT School of Science Dean’s Postdoctoral Fellow, Massachusetts Institute of Technology, US
2019-2025 Graduate Research Assistant, Atmospheric and Climate Science, University of Washington, US
2018-2019 Consultant, ICF Consulting, inc., Washington, DC
2014-2018 Bachelor of Arts in Chemistry and Earth Sciences (double major), Dartmouth College, NH

Download CV here.

Contact

ursulaj@mit.edu

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