Ann Middlebrook

Research Chemist

Aerosol Properties & Processes



NOAA Chemical Sciences Laboratory
325 Broadway, R/CSL2
Boulder, CO 80305 USA


Dr. Middlebrook is a Research Chemist at the NOAA Chemical Sciences Laboratories (CSL) in Boulder, Colorado. She joined the Laboratory in 1994 as a Department of Energy Distinguished Postdoctoral Research Fellow in Global Change after receiving degrees in chemistry from the University of California at Berkeley and Stanford University. Her principle research interest is the chemical measurement of atmospheric aerosols to advance the understanding of their formation, chemical transformations and transport in the atmosphere, and the impact of these aerosols on air quality and climate. Her initial research here involved laboratory and field measurements with the Particle Analysis by Laser Mass Spectrometry (PALMS) instrument. Her current research efforts concentrate on the development, characterization, and deployment of a compact Time-of-Flight Aerosol Mass Spectrometer (c-ToF AMS) and a Particle-into-Liquid Sampler (PiLS) for airborne chemical measurements of tropospheric aerosols along with analyzing the data and interpreting the results. She has participated in several NOAA ground-based and airborne field programs. In addition to measuring the chemical composition of aerosols, Dr. Middlebrook has collaborated with other scientists in developing new methods for aerosol sampling, including the Pumped Counterflow Virtual Impactor (PCVI) and a Pressure-Controlled Inlet (PCI) for airborne sampling. Her AMS calibration work on the effect of particle phase has been incorporated into a parameterization of the composition-dependent collection efficiency that is used in post-processing of all AMS data.


1994:  PhD Physical Chemistry, Stanford University
1986:  BS Chemistry, cum laude, University of California, Berkeley


Aerosol Composition and Formation: In-situ observations of aerosol chemical composition primarily with the c-ToF AMS with the light-scattering module, aerosol emission and secondary formation downwind of various sources, and phase-partitioning between trace gases and aerosols.
Heterogeneous Chemistry: Study of reactions occurring inside or at the surface of aerosols and their potential impact on air quality and climate.
Aerosol Instrumentation: Development and application of new techniques for precise, fast-time reponse atmospheric aerosol chemical composition measurements.

National Oceanic and Atmospheric Administration

last modified: October 2, 2020