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Organic carbon (OC) is a highly diverse class of compounds that represents a small but critical fraction of the atmosphere’s chemical composition. Volatile organic compounds (VOCs), when combined with nitrogen oxides (NOx), can produce tropospheric ozone (O3), a regulated air pollutant. OC also represents a large and growing fraction of aerosol mass, either through direct emissions from sources like fossil combustion and biomass burning, or through secondary chemistry by the oxidation and subsequent reduction of vapor pressure of VOCs leading to condensational growth. Clouds droplets and precipitation can contain additional OC due to the dissolution of soluble organic gases to the aqueous phase. OC has abundantly been found in aqueous samples of clouds, fog, and precipitation, exposing these compounds to unique aqueous chemical reactions and wet deposition. However, the concentrations and controlling factors of atmospheric aqueous organic carbon remain highly unconstrained. Cloud water measurements at Whiteface Mountain in the Adirondack Mountains in upstate New York have revealed an increasing trend of Total Organic Carbon (TOC), with annual median concentrations doubling in 14 years, possibly signaling a growing trend in atmospheric OC. However, the causes and potential consequences of this trend remain unclear. Another question that has yet to be explored is if this trend in OC extends beyond WFM. To answer this question, this work explores the trends of WFM cloud water and 4 additional long-term cloud water and wet deposition datasets that have measured TOC or dissolved OC (DOC) throughout the Northeast US. These sites include Mt Washington, NH, Hubbard Brook NH, Thompson Farm NH, and Sleepers River Vermont. This work will also discuss potential hypotheses driving this increasing trend including increased biomass burning influence and increased biogenic emissions in the region.
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This content will become publicly available on January 15, 2026
Preliminary Study of the Microbiome at Whiteface Mountain (WFM)
Whiteface Mountain (WFM) in northern NY State is the site of a historic mountaintop atmospheric observatory with an ongoing cloud water chemistry monitoring program that has been operating every summer (June through September) since 1994. Though long-term chemical analysis has been conducted, no analysis on the microbiome has been completed at WFM. Over the years, a new chemical regime has been reported in the cloudwater with missing analytes. Knowing how microbes can interact with chemicals, we hypothesize microbes are partially responsible for this shift and are crucial in understanding the chemical background of clouds. To start this study, cloudwater filters have been analyzed both chemically and microbially. Chemically, weighted averages have been calculated for each cloudwater filter based on the chemical composition of the clouds. Microbially, we have begun DNA extractions and subsequent metagenomic analysis using the Oxford Nanopore MinION using a select number of cloud water filters from 2024. Overall, this study aims to build upon microbial work accomplished by the Puy de Dôme groups and discuss the collection, storage, and analysis of cloudwater filters to connect the chemical to the microbial at WFM.
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- Award ID(s):
- 1945563
- PAR ID:
- 10570973
- Publisher / Repository:
- American Meteorological Society
- Date Published:
- Format(s):
- Medium: X
- Location:
- New Orleans, LA
- Sponsoring Org:
- National Science Foundation
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Russell, Lynn M (Ed.)Abstract. Organic acids represent an important class of compounds in the atmosphere, but there is limited research investigating their chemical production, particularly in the northeast United States. To improve our understanding of organic acid sources, a modeling analysis was performed for air masses reaching the summit of Whiteface Mountain (WFM), New York, where measurements of organic acids in cloud water have been collected. The analysis focuses on a pollution event associated with a heat wave that occurred on 1–2 July 2018 that exhibited unusually high concentrations of formic (HCOOH), acetic (CH3COOH), and oxalic (OxAc) acid in cloud water. The gas-phase production of organic acids for this pollution event was modeled using a combination of the regional transport model Weather Research and Forecasting Model with Chemistry (WRF-Chem), which gives information on transport and environmental factors affecting air parcels reaching WFM, and the Lagrangian chemical box model BOXMOX, which allows analysis of chemistry with different chemical mechanisms. Two chemical mechanisms are used in BOXMOX: (1) the Model for Ozone and Related chemical Tracers (MOZART T1) and (2) the Master Chemical Mechanism (MCM) version 3.3.1. The WRF-Chem results show that air parcels sampled during the pollution event at WFM originated in central Missouri, which has strong biogenic emissions of isoprene. Many air parcels were influenced by emissions of nitrogen oxides (NOx) from the Chicago metropolitan area. The gas-phase oxidation of isoprene and its related oxidation products was the major source of HCOOH and CH3COOH, but both mechanisms substantially underproduced both acids compared to observations. A simple gas–aqueous mechanism was included to investigate the role of aqueous chemistry in organic acid production. Aqueous chemistry did not produce more HCOOH or CH3COOH, suggesting missing chemical sources of both acids. However this aqueous chemistry was able to explain the elevated concentrations of OxAc. Anthropogenic NOx emissions from Chicago had little overall impact on the production of all three organic acids. Further studies are required to better constrain gas and aqueous production of low-molecular-weight organic acids.more » « less
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