Field Methods: We propose to make measurements of fine particle composition using FTIR, XRF, and AMS techniques as part of the SOAS campaign. The instruments are housed in a 20’x8’ trailer with 3 m isokinetic inlet. The Russell group will collect fine particle mass on Teflon filters for quantification of organic functional group concentrations by FTIR spectroscopy and elemental concentrations by X-ray fluorescence (XRF). These techniques allowed not only for quantitative characterization of the organic composition of fine aerosol, but also identification of source categories and quantitative source contributions through the use of elemental tracers and positive matrix factorization (PMF). The sample collection will be conducted alongside simultaneous aerosol mass spectrometer (AMS) measurements, allowing for comparison of total organic mass and providing complementary information on organic composition (mass spectral fragments as opposed to chemical functional groups). Fine particle mass will be collected on Teflon filters for with both PM1 (4-6 hr) and PM2.5 (24 hr) cyclones. All filters will be analyzed by FTIR to quantify organic functional group concentrations, and selected filters will be analyzed by XRF to compare and validate ongoing IMPROVE sampling protocols. We will also collect samples for scanning transmission X-ray microscopy (STXM) near-edge X-ray absorption fine structure (NEXAFS) for selected periods. While limited in sample number, the unique single-particle organic functional group and morphology measurements provided by STXM-NEXAFS provides one-of-a-kind insight into the composition and structure of individual aerosol particles. We will collect approximately 10 samples for this analysis at the Look Rock site and archive an additional 40 samples for analysis if resources permit at a later date. The Ziemann group will also use spectrophotometric methods to analyze functional groups in a subset of aerosol filter samples (due to higher method detection limits and the need for larger samples) collected by the Russell group at Centerville, AL, and Look Rock, TN. In addition, we plan to exchange samples with the Surratt group (also located at Look Rock, TN) to augment inter-comparison of their tracer-compound methods with our functional group based methods, for both atmospheric and chamber sampling. The Russell group will also measure aerosol size-resolved chemical composition with high time resolution using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and black carbon components of the aerosol using a single particle soot photometer (SP2), which provide distinctive characteristics to quantify the contributions of biogenic and anthropogenic sources. Measurements of inorganic and organic fine particle composition and size distributions (near 100% transmissions for 60-600 nm, and partial transmission extending to ~30 nm and ~1.5 µm) will be conducted using an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS). This operation scheme will provide high time resolution measurements of inorganic and organic composition (5 min), mass fragments (5 min), elemental composition (10 min), single particles (2 hr), and mass fragment size distributions (1-4 hr).

NARSTO_SOS99NASH_G-1_AIR_CHEMISTRY_DATA is the North American Research Strategy for Tropospheric Ozone (NARSTO) SOS99 Nashville Department of Energy (DOE) G-1 Air Chemistry Data product. Data was collected via the G-1 aircraft deployed during the 1999 campaign to make measurements within the Nashville urban plume. These in situ, semi-Lagrangian measurements, in conjunction with surface-based observations independently made at the Polk Building and at the Cornelia Fort site, allowed quantification of the following: a) ozone production/loss rates, b) ozone production efficiency and c) NOx loss rates within this plume. Mechanical problems with the G-1 aircraft precluded making additional measurements. North American Research Strategy for Tropospheric Ozone (NARSTO), which has since disbanded, was a public/private partnership, whose membership spanned across government, utilities, industry, and academe throughout Mexico, the United States, and Canada. The primary mission was to coordinate and enhance policy-relevant scientific research and assessment of tropospheric pollution behavior; activities provide input for science-based decision-making and determination of workable, efficient, and effective strategies for local and regional air-pollution management. Data products from local, regional, and international monitoring and research programs are still available.

Data set contains CMAQ model output for Look Rock, Tennessee and Centreville, Alabama during summer 2013. This dataset is associated with the following publication: Liu, J., L. Russell, G. Ruggeri, S. Takahama, M. Claflin, P. Ziemann, H. Pye, B. Murphy, L. Xu, N. Ng, K. McKinney, S. Hapsari Budisulistiorini, T. Bertram, A. Nenes, and J. Surratt. Regional Similarities and NOx‐Related Increases in Biogenic Secondary Organic Aerosol in Summertime Southeastern United States. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES. American Geophysical Union, Washington, DC, USA, 123(18): 10,620-10,636, (2018).

Data set contains CMAQ model output for Look Rock, Tennessee and Centreville, Alabama during summer 2013. This dataset is associated with the following publication: Liu, J., L. Russell, G. Ruggeri, S. Takahama, M. Claflin, P. Ziemann, H. Pye, B. Murphy, L. Xu, N. Ng, K. McKinney, S. Hapsari Budisulistiorini, T. Bertram, A. Nenes, and J. Surratt. Regional Similarities and NOx‐Related Increases in Biogenic Secondary Organic Aerosol in Summertime Southeastern United States. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES. American Geophysical Union, Washington, DC, USA, 123(18): 10,620-10,636, (2018).

Field Methods: The following instruments provided by Handix Scientific will be installed at the Look Rock Site in Great Smoky Mountains National Park: Open-Path Cavity Ringdown Spectrometer (OPCRDS), Cavity Attenuated Phase Shift PM Extinction Monitor (CAPS). These instruments will run autonomously and sample ambient air at the site. Data from these instruments will be compared with publicly available data from the Interagency Monitoring of Protected Visual Environments (IMPROVE) program.

This research used data mining approaches to better understand factors affecting the formation of secondary organic aerosol (SOA). Although numerous laboratory and computational studies have been completed on SOA formation, it is still challenging to determine factors that most influence SOA formation. Experimental data were based on previous work described by Offenberg et al. (2017), where volume concentrations of SOA were measured in 139 laboratory experiments involving the oxidation of single hydrocarbons under different operating conditions. Three different data mining methods were used, including nearest neighbor, decision tree, and pattern mining. Both decision tree and pattern mining approaches identified similar chemical and experimental conditions that were important to SOA formation. Among these important factors included the number of methyl groups, the number of rings and the presence of dinitrogen pentoxide (N2O5). This dataset is associated with the following publication: Olson, D., J. Offenberg, M. Lewandowski, T. Kleindienst, K. Docherty, M. Jaoui, J.D. Krug, and T. Riedel. Data mining approaches to understanding the formation of secondary organic aerosol. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, USA, 252: 118345, (2021).

This research used data mining approaches to better understand factors affecting the formation of secondary organic aerosol (SOA). Although numerous laboratory and computational studies have been completed on SOA formation, it is still challenging to determine factors that most influence SOA formation. Experimental data were based on previous work described by Offenberg et al. (2017), where volume concentrations of SOA were measured in 139 laboratory experiments involving the oxidation of single hydrocarbons under different operating conditions. Three different data mining methods were used, including nearest neighbor, decision tree, and pattern mining. Both decision tree and pattern mining approaches identified similar chemical and experimental conditions that were important to SOA formation. Among these important factors included the number of methyl groups, the number of rings and the presence of dinitrogen pentoxide (N2O5). This dataset is associated with the following publication: Olson, D., J. Offenberg, M. Lewandowski, T. Kleindienst, K. Docherty, M. Jaoui, J.D. Krug, and T. Riedel. Data mining approaches to understanding the formation of secondary organic aerosol. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, USA, 252: 118345, (2021).

On 25 July 2016, helicopter-based measurements were made of the volcanic gases emitted from Mount Cleveland, Alaska, USA. An upward-looking differential optical absorption spectroscopy (DOAS) system was used to measure incident scattered solar ultraviolet radiation while traversing beneath the plume on multiple occasions. These data were used to derive volcanic SO2 emission rates. Additionally, a Multicomponent Gas Analyzer System (Multi-GAS) was used to make measurements of trace gas concentrations while on a dedicated measurement flight passing through the volcanic plume. Radiance spectra and gas compositions were both recorded at 1 second time resolution. Each spectrum and gas measurement was stamped with the GPS time and location. Each spectrum was saved in a separate ASCII file which includes 2048 radiances measured in the 285 - 430 nm spectral region and metadata associated with each acquisition. The Multi-GAS measurements are saved in a spreadsheet in the *.csv format. In addition to the helicopter-based measurements, ultraviolet imagery of the volcanic plume emitting from Mount Cleveland was collected on 24 July between 18:00 and 19:30 UTC using a ground-based SO2 camera instrument located 3.4 km east of the volcano's summit. This imagery was used to quantify the absorption of light by SO2 in the volcano's plume, resulting in a time series of SO2 emission rates. For more information see the associated interpretive publication: Werner C., Rasmussen D.J., Plank T., Kelly P.J., Kern C., Lopez T., Gliss J., Power J., Roman D.C., Izbekov P., Lyons J. (2020). Linking subsurface to surface using gas emission and melt inclusion data at Mount Cleveland volcano, Alaska. Geochemistry, Geophysics, Geosystems. https://doi.org/10.1029/2019GC008882

On 25 July 2016, helicopter-based measurements were made of the volcanic gases emitted from Mount Cleveland, Alaska, USA. An upward-looking differential optical absorption spectroscopy (DOAS) system was used to measure incident scattered solar ultraviolet radiation while traversing beneath the plume on multiple occasions. These data were used to derive volcanic SO2 emission rates. Additionally, a Multicomponent Gas Analyzer System (Multi-GAS) was used to make measurements of trace gas concentrations while on a dedicated measurement flight passing through the volcanic plume. Radiance spectra and gas compositions were both recorded at 1 second time resolution. Each spectrum and gas measurement was stamped with the GPS time and location. Each spectrum was saved in a separate ASCII file which includes 2048 radiances measured in the 285 - 430 nm spectral region and metadata associated with each acquisition. The Multi-GAS measurements are saved in a spreadsheet in the *.csv format. In addition to the helicopter-based measurements, ultraviolet imagery of the volcanic plume emitting from Mount Cleveland was collected on 24 July between 18:00 and 19:30 UTC using a ground-based SO2 camera instrument located 3.4 km east of the volcano's summit. This imagery was used to quantify the absorption of light by SO2 in the volcano's plume, resulting in a time series of SO2 emission rates. For more information see the associated interpretive publication: Werner C., Rasmussen D.J., Plank T., Kelly P.J., Kern C., Lopez T., Gliss J., Power J., Roman D.C., Izbekov P., Lyons J. (2020). Linking subsurface to surface using gas emission and melt inclusion data at Mount Cleveland volcano, Alaska. Geochemistry, Geophysics, Geosystems. https://doi.org/10.1029/2019GC008882

Soluble acidic gases and aerosols (SAGA) were collected with two related installations; a mist chamber/ion chromatography (MC/IC) system and a paired bulk aerosol system. The MC/IC system measures in situ atmospheric distributions of nitric acid (plus < 1 um NO3 aerosol) and fine (< 1 um) aerosol sulfate at an approximately 80-second interval. The paired bulk aerosol system collects particulates onto filters for subsequent analysis. Collected filters were first extracted with water to obtain the water-soluble (WS) constituents and then extracted again using methanol to collect the methanol soluble (MS) fraction. The light absorption of filtered extracts was measured from 300 to 700 nm. Ion chromatography on aqueous extracts of the bulk aerosol samples collected on Teflon filters were used to quantify soluble ions (Cl-, Br-, NO3-, SO42-, C2O42-, Na+, NH4+, K+, Ca+, and Mg+). The SAGA system is provided by the University of New Hampshire (UNH).