About

Sarah Brooks is a Professor and the Director of the Center for Atmospheric Chemistry and the Environment at Texas A&M University College of Arts and Sciences. Her research focuses on understanding particles in the atmosphere and the clouds that form on them, with the aim of improving the understanding and quantification of global warming. Her work involves developing novel analytical techniques to observe ice cloud nucleation under atmospheric conditions, combining field studies and laboratory experiments to explore how aerosol particles influence cloud formation and properties. Brooks investigates the chemical composition, surface reactions, and shape of aerosols, and their impact on cloud formation, radiative properties, and air quality. Her research also includes studying how pollutants travel and affect regional air quality, as well as participating in large-scale global campaigns to measure aerosol concentrations and compositions. Her efforts aim to elucidate complex aerosol/cloud interactions and enhance climate change predictions. Brooks holds a Ph.D. in Analytical Chemistry from the University of Colorado and a B.S. in Chemistry from MIT. She has received several awards, including the Presidential Early Career Award in Science and Engineering and the NSF CAREER Award, and is actively involved in advancing atmospheric sciences through her research and leadership.

Research topics

• Geology
• Environmental science
• Oceanography
• Environmental chemistry
• Chemistry
• Meteorology
• Ecology
• Geography
• Atmospheric sciences
• Biology

Selected publications

• Understanding aerosol properties in convective outflows during TRACER

  Aerosol Science and Technology · 2026-01-20

  articleOpen accessSenior authorCorresponding

  Convective outflow boundaries commonly form across the southeastern U.S., often originating from storms initiated along sea-breeze fronts. As outflows spread, merge, and collide, they frequently trigger secondary convection in air masses already modified by primary storm outflow. This resulting air mass carries a distinctive aerosol population, which can influence the development of secondary convective cells. During the U.S. DOE TRACER field campaign in summer 2022, we investigated how outflows affect aerosol size, composition, and hygroscopicity across Greater Houston, Texas. Using a novel detection algorithm, we identified and verified 72 outflow boundaries from surface meteorological observations. In the relatively simple continental environment northwest of Houston, a common relationship emerged between CCN-inferred hygroscopicity (<i>κ</i>) and size-resolved aerosol concentrations. The <i>κ</i> of aerosols typically decreased in size ranges where aerosol concentrations increased following outflow passage and increased where concentrations decreased. In contrast, at the Atmospheric Radiation Measurement’s (ARM) fixed site in La Porte, Texas, the aerosol response depended on outflow direction, shaped by concentrated industrial and shipping activity to the north and south/southeast along the Houston Ship Channel. Concurrent size distribution and composition changes suggested case-specific variability in <i>κ</i>, with either reinforcing or offsetting effects. Outflows passing over industrial/shipping sectors often promoted less hygroscopic aerosol populations while cleaner residential outflows often favored more hygroscopic aerosol populations. These results highlight key aerosol changes following outflow passage, providing a foundation for improved understanding of aerosol-cloud interactions related to secondary convection initiation along or in the wake of outflow boundaries.

  PublisherDOI

• Understanding aerosol properties in convective outflows during TRACER

  Figshare · 2026-01-01

  articleOpen accessSenior author

  Convective outflow boundaries commonly form across the southeastern U.S., often originating from storms initiated along sea-breeze fronts. As outflows spread, merge, and collide, they frequently trigger secondary convection in air masses already modified by primary storm outflow. This resulting air mass carries a distinctive aerosol population, which can influence the development of secondary convective cells. During the U.S. DOE TRACER field campaign in summer 2022, we investigated how outflows affect aerosol size, composition, and hygroscopicity across Greater Houston, Texas. Using a novel detection algorithm, we identified and verified 72 outflow boundaries from surface meteorological observations. In the relatively simple continental environment northwest of Houston, a common relationship emerged between CCN-inferred hygroscopicity (<i>κ</i>) and size-resolved aerosol concentrations. The <i>κ</i> of aerosols typically decreased in size ranges where aerosol concentrations increased following outflow passage and increased where concentrations decreased. In contrast, at the Atmospheric Radiation Measurement’s (ARM) fixed site in La Porte, Texas, the aerosol response depended on outflow direction, shaped by concentrated industrial and shipping activity to the north and south/southeast along the Houston Ship Channel. Concurrent size distribution and composition changes suggested case-specific variability in <i>κ</i>, with either reinforcing or offsetting effects. Outflows passing over industrial/shipping sectors often promoted less hygroscopic aerosol populations while cleaner residential outflows often favored more hygroscopic aerosol populations. These results highlight key aerosol changes following outflow passage, providing a foundation for improved understanding of aerosol-cloud interactions related to secondary convection initiation along or in the wake of outflow boundaries.

  PublisherDOI

• Detecting supramolecular organic nanoparticles during heat wave

  Science · 2026-02-12

  article

  New particle formation (NPF) represents a major source of tropospheric fine aerosols. A common viewpoint is that NPF hinges thermodynamically on the volatility of condensing species and is unfavorable at high temperatures. From an intensive field campaign, we observed frequent NPF events during a heat wave. Size-resolved chemical composition of nanoparticles down to 3 nanometers was first measured, unraveling a dominant presence of carboxylic acids. Our work uncovers a spontaneous mechanism to produce supramolecular nanoparticles through self-assembly of organic acids. This discovery explains not only the unexpected NPF at high temperatures but also its ubiquitous occurrence under diverse atmospheric conditions. As global warming leads to more frequent and intense heat waves, our findings open avenues for assessing the impacts of aerosols on cloud formation, public health, and climate.

  PublisherDOI

• Supplementary material to "Aerosol Vertical Distributions Shaped by Boundary Layer Dynamics in a Coastal Urban Environment: Insights from the TRACER Campaign"

  2026-04-02

  articleOpen accessSenior author
  PublisherDOI

• Aerosol Vertical Distributions Shaped by Boundary Layer Dynamics in a Coastal Urban Environment: Insights from the TRACER Campaign

  2026-04-02

  articleOpen accessSenior author

  Abstract. Aerosol vertical distributions are a major source of uncertainty in quantifying aerosol–cloud–climate interactions. Using observations collected during the 2022 TRACER campaign in Houston, Texas, we investigate how Atmospheric boundary layer dynamics shape the vertical structure of aerosol populations in a coastal urban environment. Our lidar retrieval combines micropulse lidar backscatter with ground-based aerosol measurements to obtain aerosol concentration profiles. We introduce a new parameterized fitting function that captures the characteristic S-shaped aerosol profiles associated with boundary layer processes. This parameterization is applied to case studies demonstrating how boundary-layer dynamics, including turbulent mixing, capping inversion strength, and sea-breeze circulations, govern aerosol vertical distributions. Finally, we estimate aerosol vertical profiles from boundary layer height and gradients in potential temperature profile using our proposed aerosol profile parameterization function. These findings provide a physically grounded parameterization for inferring aerosol vertical profiles in locations where aerosol sampling is limited to surface measurements.

  PublisherDOI

• Glass Transition Temperatures of Organic Mixtures from Isoprene Epoxydiol-Derived Secondary Organic Aerosol

  UNC Libraries · 2026-02-11

  articleOpen accessSenior author

  The phase states and glass transition temperatures (<em>T</em>_g) of secondary organic aerosol (SOA) particles are important to resolve for understanding the formation, growth, and fate of SOA as well as their cloud formation properties. Currently, there is a limited understanding of how <em>T</em>_g changes with the composition of organic and inorganic components of atmospheric aerosol. Using broadband dielectric spectroscopy, we measured the <em>T</em>_g of organic mixtures containing isoprene epoxydiol (IEPOX)-derived SOA components, including 2-methyltetrols (2-MT), 2-methyltetrol-sulfate (2-MTS), and 3-methyltetrol-sulfate (3-MTS). The results demonstrate that the <em>T</em>_g of mixtures depends on their composition. The Kwei equation, a modified Gordon-Taylor equation with an added quadratic term and a fitting parameter representing strong intermolecular interactions, provides a good fit for the <em>T</em>_g-composition relationship of complex mixtures. By combining Raman spectroscopy with geometry optimization simulations obtained using density functional theory, we demonstrate that the non-linear deviation of <em>T</em>_g as a function of composition may be caused by changes in the extent of hydrogen bonding in the mixture.

  PublisherDOI

• Understanding aerosol properties in convective outflows during TRACER

  Figshare · 2026-01-01

  articleOpen accessSenior author

  Convective outflow boundaries commonly form across the southeastern U.S., often originating from storms initiated along sea-breeze fronts. As outflows spread, merge, and collide, they frequently trigger secondary convection in air masses already modified by primary storm outflow. This resulting air mass carries a distinctive aerosol population, which can influence the development of secondary convective cells. During the U.S. DOE TRACER field campaign in summer 2022, we investigated how outflows affect aerosol size, composition, and hygroscopicity across Greater Houston, Texas. Using a novel detection algorithm, we identified and verified 72 outflow boundaries from surface meteorological observations. In the relatively simple continental environment northwest of Houston, a common relationship emerged between CCN-inferred hygroscopicity (<i>κ</i>) and size-resolved aerosol concentrations. The <i>κ</i> of aerosols typically decreased in size ranges where aerosol concentrations increased following outflow passage and increased where concentrations decreased. In contrast, at the Atmospheric Radiation Measurement’s (ARM) fixed site in La Porte, Texas, the aerosol response depended on outflow direction, shaped by concentrated industrial and shipping activity to the north and south/southeast along the Houston Ship Channel. Concurrent size distribution and composition changes suggested case-specific variability in <i>κ</i>, with either reinforcing or offsetting effects. Outflows passing over industrial/shipping sectors often promoted less hygroscopic aerosol populations while cleaner residential outflows often favored more hygroscopic aerosol populations. These results highlight key aerosol changes following outflow passage, providing a foundation for improved understanding of aerosol-cloud interactions related to secondary convection initiation along or in the wake of outflow boundaries.

  PublisherDOI

• Studying Aerosol, Clouds, and Air Quality in the Coastal Urban Environment of Southeastern Texas

  Bulletin of the American Meteorological Society · 2025-08-04 · 3 citations

  article

  Abstract A multi-agency succession of field campaigns was conducted in southeastern Texas during July 2021 through October 2022 to study the complex interactions of aerosols, clouds and air pollution in the coastal urban environment. As part of the Tracking Aerosol Convection interactions Experiment (TRACER), the TRACER- Air Quality (TAQ) campaign the Experiment of Sea Breeze Convection, Aerosols, Precipitation and Environment (ESCAPE) and the Convective Cloud Urban Boundary Layer Experiment (CUBE), a combination of ground-based supersites and mobile laboratories, shipborne measurements and aircraft-based instrumentation were deployed. These diverse platforms collected high-resolution data to characterize the aerosol microphysics and chemistry, cloud and precipitation micro- and macro-physical properties, environmental thermodynamics and air quality-relevant constituents that are being used in follow-on analysis and modeling activities. We present the overall deployment setups, a summary of the campaign conditions and a sampling of early research results related to: (a) aerosol precursors in the urban environment, (b) influences of local meteorology on air pollution, (c) detailed observations of the sea breeze circulation, (d) retrieved supersaturation in convective updrafts, (e) characterizing the convective updraft lifecycle, (f) variability in lightning characteristics of convective storms and (g) urban influences on surface energy fluxes. The work concludes with discussion of future research activities highlighted by the TRACER model-intercomparison project to explore the representation of aerosol-convective interactions in high-resolution simulations.

  PublisherDOI

• Aerosol Physicochemical Mixing State and Cloud Nucleation Potential during Tracking Aerosol Convection Interactions Experiment (TRACER) Campaign

  Environmental Science & Technology · 2025-07-18 · 5 citations

  articleSenior authorCorresponding

  Aerosol-cloud interactions remain a major source of uncertainty in estimating global radiative forcing due to the complex nature of the aerosol physicochemical properties. This study investigates the physicochemical characteristics of aerosols collected during the DOE's TRacking Aerosol Convection interactions Experiment (TRACER) campaign, conducted from June to September 2022 in the Greater Houston area. Aerosols were sampled at coastal (Galveston) and inland (Hempstead and Jersey Village) sites during sea-breeze initiated convection and outflow events and analyzed using Raman microspectroscopy. Galveston's aerosols primarily consisted of organic compounds, while Hempstead featured mainly inorganic salts (e.g., ammonium sulfate) and secondary organic aerosols. Organic aerosols were more abundant in Galveston (73%) than in Hempstead (65%). Particles exhibited diverse morphologies including homogeneous, core-shell, and complex structures. Homogeneous particles dominated at both sites, though Hempstead showed a higher fraction of core-shell particles. Cloud condensation nuclei (CCN) concentrations were 5 times higher at the inland sites than at the coast at a supersaturation of 0.2%, and this difference increased to 13 times higher at a 1.2% supersaturation. During sampling of the outflow of convective storm systems, distinct changes in aerosol size, morphology, and mixing state led to a significant increase in CCN activity at the inland (Jersey Village) site. These findings emphasize the impacts of atmospheric processing on aerosols and highlight the need to incorporate physicochemical variability into models to improve predictions of aerosol-cloud interactions and climate effects.

  PublisherDOI

• Quantifying the Spatial and Temporal Distributions of Volatile Chemical Products (VCPs) in the Greater Houston Area

  Environmental Science & Technology · 2025-06-26 · 2 citations

  articleOpen access

  -chlorobenzotrifluoride (PCBTF), and 2,2,4-trimethyl-1,3-pentanediol isobutyrate (Texanol), were collected in winter and summer 2023. Several compounds exhibited significantly higher averaged concentrations, with pronounced spatial and seasonal variability, distinguishing Houston from urban areas in the temperate and cooler climate zone. A customized box model was employed to estimate seasonal emissions for the Greater Houston Area, showing that emissions of most VCPs were significantly higher during the summer. This study provides critical insights into the distribution and emission of VCPs in a subtropical metropolitan area, advancing methods for assessing VCP emissions and concentrations across cities and improving understandings of their impacts on air quality, climate, and public health.

  PublisherDOI

Recent grants

• Collaborative Research: Why Does Oxidation Improve Freezing? Using Laboratory Measurements and Molecular Simulations to Investigate Heterogeneous Ice Nucleation on Carbon Surfaces

  NSF · $220k · 2013–2016

• CAREER: Chemical Processing and Cloud Nucleation Activity of Soot Aerosol

  NSF · $628k · 2006–2012

• Viscous Organic Liquids and Catalysis of Atmospheric Ice Nucleation

  NSF · $360k · 2018–2023

• Identification of Cloud-Nucleating and Ice-Nucleating Biological Aerosol Sources

  NSF · $590k · 2015–2019

• Collaborative Research: Quantifying the Role of Pollen in Cloud Formation through Measurements and Modeling

  NSF · $358k · 2018–2022

Frequent coauthors

• Margaret A. Tolbert

  University of Colorado Boulder

  37 shared

• Matthew E. Wise

  Maryland Aerospace (United States)

  29 shared

• A. J. Prenni

  Colorado State University

  28 shared

• Naruki Hiranuma

  Karlsruhe Institute of Technology

  23 shared

• D. J. Cziczo

  Purdue University West Lafayette

  21 shared

• Jessica Mirrielees

  Texas A&M University

  20 shared

• Paul J. DeMott

  Colorado State University

  20 shared

• Daniel C. O. Thornton

  Texas A&M University

  19 shared

Labs

• Center for Atmospheric Chemistry and the EnvironmentPI

Education

• Ph.D., Chemistry

  University of Colorado Boulder

  2002

Awards & honors

• Texas A&M Impact Fellowship (2017)
• PECASE 2007, Presidential Early Career Award in Science and…