Organic Acids in Cloud Water, Aerosols, and Cloud Droplet Residuals at the Summit of Whiteface Mountain (WFM)

ARCHANA TRIPATHY, Christopher Lawrence, Haider Khwaja, Mirza M. Hussain, Elizabeth Yerger, Phil Snyder, Paul Casson, Rudra Patel, Sarah Lombardo, Lily Hammond, Richard Brandt, Scott McKim, William May, James Schlemmer, Dan Kelting, James Schwab, Sara Lance, University at Albany

     Abstract Number: 665
     Working Group: Aerosols, Clouds and Climate

Abstract
Organic compounds in the atmosphere play a pivotal role in atmospheric chemistry, and clouds are significant in the genesis and alteration of these compounds. Di-carboxylic organic anions such as oxalate serve as tracers for aqueous processing. This poster details our findings from summer measurements of three major organic acids (formic acid, acetic acid, oxalic acid), as well as inorganic anions (sulfate, chloride, nitrate) and cations (sodium, potassium, ammonium, calcium, magnesium) in cloud water, aerosol, and cloud droplet residual samples collected at the summit of Whiteface Mountain (WFM) in the Adirondack Mountains, northern New York State. We also evaluate the contribution of these organic acids to water-soluble organic carbon (WSOC) concentrations. Previous studies have explored the oxalate: WSOC ratio with ozone levels, aiming to deduce the influence of biogenic Volatile Organic Compounds (VOCs) on Secondary Organic Aerosol (SOA) formation from nearby forest ecosystems. Our poster presents new observations that significantly broaden this understanding by comparing to diverse global environments and analyzing both cloud water and aerosol phases. Additionally, we introduce oxalate: sulfate ratios from our dataset, proposed by other researchers as a key indicator of aqueous processing due to the enhanced production rates of these ions by liquid water content (sulfate ion) or droplet surface area (oxalate ion). We compare the observed range of oxalate: sulfate ratios with those from field campaigns conducted in other regions. Moreover, for the first time, we examine the relationship between ammonium and organic acids across cloud water, aerosol, and droplet residual samples collected in 2023, and discuss the influence of wildfire smoke on these dynamics.