Five Questions with Rachel E. O’Brien

Rachel E. O’Brien, Assistant Professor
Department of Chemistry
William & Mary

1. How did you get involved in the aerosol science community?

My first introduction to aerosol science occurred when I reached out to Allen Goldstein about joining his group in graduate school. I knew I liked mass spectrometry, and I was interested in questions related to the environment. I went to a group meeting where one of his students was presenting on organic aerosol particles, and I was fascinated. I had previously experienced breathing difficulties due to poor air quality when I had a very bad case of bronchitis in college and then drove through the industrial section of Kansas City. It was really interesting to finally learn about one of the components in the air that was making it hard for me to breath during that car trip. For my PhD, I ended up working on a project with Allen and Alexander Laskin (then at Pacific Northwest National Laboratory) to use mass spectrometry to measure chemicals in aerosol particles that I collected during a field campaign in Bakersfield, CA.

2. Which people or programs in our field have been the most influential to you and your path, or who have most influenced your ideas about aerosol research?

My PhD with Allen Goldstein opened the door to the aerosol community and shaped my approach to study design and data analysis. My first postdoc at Lawrence Berkeley National Laboratory was a big shift in methods, but a fascinating shift in perspective because I went from bulk analysis with mass spectrometry to single particle imaging. I don’t think I will ever forget collecting my first image of an aerosol particle and seeing the sharp edge of the NaCl crystal. My second postdoc with Jesse Kroll provided me with the skill set to do laboratory studies and helped me build a quantitative skill set, giving me more breadth in the types of science questions I could ask. As a new faculty member, I’ve been privileged to work with so many wonderful collaborators including Marina Vance, Delphine Farmer, and everyone in the Indoor Chemistry community; Chris Cappa on wildfire smoke photo-bleaching; Sergey Nizkorodov on aerosol photolysis; the Langley Aerosol Research Group on aircraft data sets; and Andy Ault on upcoming field campaigns.

3. What is the most interesting research contribution you’ve made so far?

The idea that I find the most interesting is the concept of a significant photo-recalcitrant fraction for biogenic secondary organic aerosol. The fact that we may not be able to rely on photolysis alone to remove secondary organic aerosol mass in the atmosphere is interesting to me because it opens the door to so many other questions about aging processes or combinations of aging pathways and how they are affected by one another. I’m excited to continue research in this area to better understand the removal and bleaching rates for secondary organic aerosol and biomass burning organic aerosol in the atmosphere.

4. What challenges were completely unexpected as you began and continue to grow your own research group?

The largest challenge I’ve found is how fragmented time becomes when I’m trying to teach, mentor, train, and write. I expected to have more things on my plate, but didn’t anticipate just how wonderful having an open hour to read a new paper would become. I really value the time that I can spend thinking about science or working in lab for an afternoon to help get a new data set. The other unexpected challenge has been the Pandemic and how different research became during that first year. I really miss interacting with other people in person, and I miss being able to plan research projects without worrying about student exposure and safety from this virus. It necessitated some shifts in projects, but I’m happy with where we have been heading and I’m excited to get started on our previously delayed campaigns.

5. Are there new research directions that you see as particularly important or interesting?

I think the pandemic has really highlighted how important clean air is and how much we need to improve our indoor air quality. I’ve been really happy to see all of the work coming out that helps communicate and teach the public about this issue and how we can work to solve the problems. I’ll be especially happy to see this continue because I think that improved indoor air will help overall health and happiness for so many people. The problem of poor ventilation and indoor air quality is challenging to correct since it can require changes in the building design and our behaviours. I hope that our field is able to continue to push in this area to demonstrate how even small improvements can have a big impact.