Aerosol Scientist Spotlight: Incoming President, Leah Williams

Leah Williams
Incoming President, AAAR
Principal Scientist, Aerodyne Research

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

I came to aerosol science by being in the right place at the right time. My graduate work was in the field of ultrafast laser spectroscopy of condensed phases, which led to a postdoc at SRI International doing laser spectroscopy of small molecules. When Maggie Tolbert left to the University of Colorado, I got my start by continuing her heterogeneous reaction rate measurements. That led to a position at Aerodyne, also in heterogeneous chemistry, which evolved into working with the aerosol mass spectrometer (AMS). However, far more important than the specific research topic, was the opportunity to work with the collegial and collaborative aerosol science community. My first AAAR conference, exactly 20 years ago, was a revelation. Everyone was so engaged with real world problems, and there were so many women compared to a physics conference. I had found my professional home.

2. Which people or programs in our field have been the most influential to you and your path?

David Golden got me started in the field by taking a chance on hiring me at SRI. Then, like a true mentor, he said it wasn’t all just about the science and tried hard to teach me how to network. Doug Worsnop and Paul Davidovits brought me into the decades long Aerodyne-Boston College collaboration and introduced me to droplets and then aerosol particles. They helped me hone my proposal and paper writing skills. My Aerodyne colleagues, John Jayne, Manjula Canagaratna, Tim Onasch and Phil Croteau, among others, are a constant source of ideas, knowledge and fruitful discussions.

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

I have been part of the Aerodyne contribution to understanding atmospheric aerosol through in situ, real-time measurements of chemical composition with the AMS. My particular contribution has focused on developing and characterizing new technology, such as the PM2.5 lens, the laser vaporization technique, and the more robust monitoring version of the AMS, the aerosol chemical speciation monitor (ACSM). I’m excited to see networks of ACSMs providing ever-more distributed and detailed information about aerosol composition and aging.

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

I don’t have my own research group – our work is very much a team effort at Aerodyne, including senior and junior researchers. The advantage is having lots of collaborators and the challenge, at times, is having a separate scientific identity. Another challenge was finding a satisfactory work-life balance. I had a new baby and a three-year old when I started at Aerodyne, and Aerodyne offered me the opportunity to work part-time for many years. Now that the kids are launched, I can focus more time on my career, expand into new areas of research, and take on new challenges like AAAR leadership positions.

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

I’m interested in two different, but complementary, research directions. One is the application of high-resolution time-of-flight mass spectrometry techniques, particularly with chemical ionization sources, to gas-phase and particle-phase organic molecules in order to study new particle formation and gas-to-particle partitioning at a much more detailed level than the bulk chemical information from the AMS. The other direction is the development of low-cost sensors and distributed networks of publicly available data. Particularly with the pandemic, it is more important than ever for people to know what they are being exposed to.