Abstract View
Investigation of Brown Carbon Formation in Cloud Droplets and Ambient Particles Undergoing Drying
VIKRAM PRATAP, Michael Battaglia Jr., Amy Christiansen, Annmarie Carlton, Christopher Hennigan, University of Maryland, Baltimore County
Abstract Number: 322
Working Group: Aerosol Chemistry
Abstract
Recent laboratory studies have reported the formation of light-absorbing organic carbon compounds (brown carbon, BrC) in aqueous particles undergoing drying. Atmospheric particles undergo humidification-drying cycles and most clouds are not precipitating, which implies particle and cloud droplet drying could potentially be an important source of BrC globally. In this work, we investigated BrC formation in ambient particles sampled during the summertime in Baltimore, Maryland. In the second part of the project, we investigated drying induced BrC formation in aerosolized cloud water collected at Whiteface Mountain (WFM), Wilmington, NY. Ambient particles as well as cloud droplets did not show evidence of drying induced BrC formation. Ambient particles appear to have BrC precursor (for example, glyoxal and methylglyoxal) levels lower by 2-5 orders of magnitude in comparison to the concentrations used in laboratory experiments where drying induced BrC formation has been observed. In the cloud water samples, the BrC precursor level was likely depleted during the regional transport of air masses reaching WFM. The implications of this work on the atmospheric budget of BrC are discussed.