2025 Talented 12: Alison Bain

When atmospheric chemist Alison Bain looks back on her career path, she sees a winding road. “The advice I always try to give undergrads is to be open to different opportunities,” she says. “I’ve done all these different and seemingly unrelated projects, but you never know when things will come in handy.”

These days, Bain works as an assistant professor at Oregon State University, where she studies the properties of single, nanometer-sized aerosol particles. Her work is expansive; Bain readily admits that it feels almost impossible to choose just one research project so early in her career.

One of her projects aims to measure how the surface tension of aerosol particles changes with size and composition. Aerosol surface tension plays a key role in cloud formation, one of the most difficult things to predict in climate models. Understanding surface tension at the single particle level could help improve the accuracy of these models, Bain says.

She is also studying atmospheric microplastics. Some of Bain’s past work showed that the tiny bits of plastic become more likely to absorb water as they age, potentially changing their optical properties in ways that could affect climate. Her research group is now artificially aging plastic particles with ultraviolet light to study those effects in more detail.

And in a new collaboration, Bain is studying the optical properties of diamond dust. In principle, tiny diamond particles could be dispersed in the atmosphere, where they would reflect sunlight back into space and cool the planet. This controversial geoengineering technique, known as stratospheric aerosol injection (SAI), is largely theoretical at this point but may offer a way to slow down global warming. Models suggest that SAI could work with many types of particles, including diamond. “It has a very high refractive index, so it would be highly reflective,” Bain explains. But little is known about the surface chemistry of diamond dust in the stratosphere, a knowledge gap her lab is well equipped to fill.

As an undergraduate at Carleton University, Bain got her first taste of research working on a project transforming silicon into nonreflective black silicon, a form used to boost the efficiency of solar cells. The thrill of applying her knowledge to a real-world chemistry problem motivated Bain to go to the University of British Columbia for a master’s degree. There, she switched gears and spent 3 years analyzing wood pulps with Raman spectroscopy to predict the properties of the paper they would form. The research was partly funded by a paper-supply company, but “I wasn’t sold on being a paper scientist for my entire life,” Bain says. So she looked for a new research topic for her PhD.

Bain found her scientific passion in the laboratory of Thomas Preston at McGill University. She was given the lab’s empty laser table and tasked with building an optical trap, a scientific instrument that uses the momentum of photons to hold tiny particles in place. Members of the research team would ultimately use the setup to trap single aerosols to study with Raman spectroscopy.

Bain was already very comfortable with Raman spectroscopy thanks to her master’s work, so despite having had almost no experience with optics, she embraced the challenge. It took her about 2 years to successfully align the mirrors and lenses of the optical trap, but in the process “I fell in love with optics and aerosols,” Bain says. “I’ve been working on this ever since.”

Bain’s PhD experience meant that when she joined Bryan Bzdek’s lab at the University of Bristol as a postdoctoral researcher, Bzdek found her exceptional at building instruments. “Put Alison in a room with a broken instrument, and she’d leave having fixed it and written three papers,” he says. “She’s really leading efforts, in terms of instrument design, to really push the limit of what you can do with single droplets.”

It’s no surprise that the first thing Bain did when she arrived at Oregon State University in 2023 was work with her students to build a kind of optical trap called optical tweezers. The system is specialized such that it can hold multiple particles at once, and Bain expects the instrument to be a workhorse in her lab. “That’s the nice thing about home-built instruments,” she explains, “you can always be modifying them for whatever purpose you want for your next experiment.”