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Measurement of the Rate and Controls of Small Particle Growth Using Ambient Air Captive Aerosol Chambers
ZIHAN ZHU, Xuanlin Du, Candice Sirmollo, Diana Ibarra-Gomez, Don Collins, University of California, Riverside
Abstract Number: 473
Working Group: Instrumentation and Methods
Abstract
New particle formation and growth plays a key role in controlling the concentration and distribution of cloud condensation nuclei (CCN), which influences the reflectivity and other properties of clouds. Uncertainties remain in quantifying particle growth rate and in characterizing aerosol behavior during real-world new particle formation events representative of a wide range of conditions and locations. In this work, two Captive Aerosol Growth and Evolution (CAGE) chambers were deployed at the DOE Atmospheric Radiation Measurement (ARM) Program's Southern Great Plains (SGP) site for a 2-month study in the spring and summer of 2021. Two identical chambers were used in parallel to study the sensitivity of particle growth to a series of additions and other changes by using one as the baseline or reference chamber and the other as the perturbation chamber. Particle growth rate and secondary aerosol properties in the two chambers were intermittently measured 24 h/day while conditions inside them mirrored those outside, with and without the controlled perturbations. The hygroscopicity, volatility, and CCN-activity characteristics of the secondary species added to the particles were characterized and related to the observed growth. The time-dependence of study-average growth rate is described using measurements from the baseline chamber. The temporal variation of particle size and properties is compared with predictions from a chemical box model. We will provide an overview of the experimental approach and will present preliminary results from the field study.