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).

Links point to the NOAA data archive of observational data and the supplement of the article which this data supports. No model data was uploaded due to its size. All updates to CMAQ used in this work are available in the public release of CMAQv5.1 (available through github or the CMAS Center). This dataset is associated with the following publication: Pye , H., D. Luecken , L. Xu, C.M. Boyd, N.L. Ng, K. Baker , B.R. Ayres, J. Bash , K. Baumann, W.P.L. Carter, E. Edgerton, J.L. Fry, B. Hutzell , D. Schwede , and P.B. Shepson. Modeling the current and future role of particulate organic nitrates in the southeastern United States. Environmental Science & Technology Letters. American Chemical Society, Washington, DC, USA, 49(24): 14195-14203, (2015).

Observed and modeled data shown in figure 2b-c. This dataset is associated with the following publication: Mao, J., A. Carlton, R. Cohen, W. Brune, S. Brown, G. Wolfe, J. Jimenez, H. Pye, N.L. Ng, L. Xu, V.F. McNeill, K. Tsigaridis, B. McDonald, C. Warneke, A. Guenther, M. Alvarado, J. de Gouw, L. Mickley, E. Liebensperger, R. Mathur, C. Nolte, R. Portmann, N. Unger, M. Tosca, and L. Horowitz. Southeast Atmosphere Studies: learning from model-observation syntheses. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, GERMANY, 18: 2615-2651, (2018).

Observed and modeled data shown in figure 2b-c. This dataset is associated with the following publication: Mao, J., A. Carlton, R. Cohen, W. Brune, S. Brown, G. Wolfe, J. Jimenez, H. Pye, N.L. Ng, L. Xu, V.F. McNeill, K. Tsigaridis, B. McDonald, C. Warneke, A. Guenther, M. Alvarado, J. de Gouw, L. Mickley, E. Liebensperger, R. Mathur, C. Nolte, R. Portmann, N. Unger, M. Tosca, and L. Horowitz. Southeast Atmosphere Studies: learning from model-observation syntheses. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, GERMANY, 18: 2615-2651, (2018).

Atmospheric organic aerosol (OA) has important impacts on climate and human health but its sources remain poorly understood. Biogenic monoterpenes and sesquiterpenes are important precursors of secondary organic aerosol (SOA), but the amounts and pathways of SOA generation from these precursors are not well constrained by observations. We propose that the less-oxidized oxygenated organic aerosol (LO-OOA) factor resolved from positive matrix factorization (PMF) analysis on aerosol mass spectrometry (AMS) data can be used as a surrogate for fresh SOA from monoterpenes and sesquiterpenes in the southeastern US. This hypothesis is supported by multiple lines of evidence, including lab-in-the-field perturbation experiments, extensive ambient ground-level measurements, and state-of-the-art modeling. We performed lab-in-the-field experiments in which the ambient air is perturbed by the injection of selected monoterpenes and sesquiterpenes, and the subsequent SOA formation is investigated. PMF analysis on the perturbation experiments provides an objective link between LO-OOA and fresh SOA from monoterpenes and sesquiterpenes as well as insights into the sources of other OA factors. Further, we use an upgraded atmospheric model and show that modeled SOA concentrations from monoterpenes and sesquiterpenes could reproduce both the magnitude and diurnal variation of LO-OOA at multiple sites in the southeastern US, building confidence in our hypothesis. We estimate the annual average concentration of SOA from monoterpenes and sesquiterpenes in the southeastern US to be roughly 2µgm−3. Dataset (csv file) contains CMAQ model predictions for locations in the southeastern US during 2012 and 2013. The species definition file (txt) defines how quantities were obtained from the model. Data in the csv files follows the writesite utility output format (https://github.com/USEPA/CMAQ/tree/5.2.1/POST/writesite). Links to additional datasets are provided. This dataset is associated with the following publication: Xu, L., H. Pye, J. He, Y. Chen, B. Murphy, and N. Ng. Experimental and model estimates of the contributions from biogenic monoterpenes and sesquiterpenes to secondary organic aerosol in the southeastern United States. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, GERMANY, 18(17): 12613-12637, (2018).

Atmospheric organic aerosol (OA) has important impacts on climate and human health but its sources remain poorly understood. Biogenic monoterpenes and sesquiterpenes are important precursors of secondary organic aerosol (SOA), but the amounts and pathways of SOA generation from these precursors are not well constrained by observations. We propose that the less-oxidized oxygenated organic aerosol (LO-OOA) factor resolved from positive matrix factorization (PMF) analysis on aerosol mass spectrometry (AMS) data can be used as a surrogate for fresh SOA from monoterpenes and sesquiterpenes in the southeastern US. This hypothesis is supported by multiple lines of evidence, including lab-in-the-field perturbation experiments, extensive ambient ground-level measurements, and state-of-the-art modeling. We performed lab-in-the-field experiments in which the ambient air is perturbed by the injection of selected monoterpenes and sesquiterpenes, and the subsequent SOA formation is investigated. PMF analysis on the perturbation experiments provides an objective link between LO-OOA and fresh SOA from monoterpenes and sesquiterpenes as well as insights into the sources of other OA factors. Further, we use an upgraded atmospheric model and show that modeled SOA concentrations from monoterpenes and sesquiterpenes could reproduce both the magnitude and diurnal variation of LO-OOA at multiple sites in the southeastern US, building confidence in our hypothesis. We estimate the annual average concentration of SOA from monoterpenes and sesquiterpenes in the southeastern US to be roughly 2µgm−3. Dataset (csv file) contains CMAQ model predictions for locations in the southeastern US during 2012 and 2013. The species definition file (txt) defines how quantities were obtained from the model. Data in the csv files follows the writesite utility output format (https://github.com/USEPA/CMAQ/tree/5.2.1/POST/writesite). Links to additional datasets are provided. This dataset is associated with the following publication: Xu, L., H. Pye, J. He, Y. Chen, B. Murphy, and N. Ng. Experimental and model estimates of the contributions from biogenic monoterpenes and sesquiterpenes to secondary organic aerosol in the southeastern United States. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, GERMANY, 18(17): 12613-12637, (2018).

These data are extracted from output from the Community Multiscale Air Quality (CMAQ) model run with inputs and simulations generated by the EQUATES project. Pollutant concentrations are pulled from the model gridcell corresponding to Baltimore, Maryland, where the measurements for this study were taken. This dataset is associated with the following publication: Sapkota, S., P. Shekhar, B. Murphy, H. Pye, C. Hennigan, and M. El-Sayed. Seasonal Assessment of Secondary Organic Aerosol Formed through Aqueous Pathways in the Eastern United States. ACS Earth and Space Chemistry. American Chemical Society, Washington, DC, USA, 9(4): 876-887, (2025).

This dataset contains data presented in the figures of the paper "On the implications of aerosol liquid water and phase separation for organic aerosol mass" published in Atmospheric Chemistry and Physics. It also links to the data archive of field observations. This dataset is associated with the following publication: Pye, H., B. Murphy, L. Xu, N. Ng, A. Carlton, H. Guo, R. Weber, P. Vasilakos, W. Appel, S. Budisulistiorini, J. Surratt, A. Nenes, W. Hu, J. Jimenez, G. saacman-VanWertz, P. Misztal, and A. Goldstein. On the implications of aerosol liquid water and phase separation for organic aerosol mass. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, GERMANY, 17: 343-369, (2017).

This dataset contains data presented in the figures of the paper "On the implications of aerosol liquid water and phase separation for organic aerosol mass" published in Atmospheric Chemistry and Physics. It also links to the data archive of field observations. This dataset is associated with the following publication: Pye, H., B. Murphy, L. Xu, N. Ng, A. Carlton, H. Guo, R. Weber, P. Vasilakos, W. Appel, S. Budisulistiorini, J. Surratt, A. Nenes, W. Hu, J. Jimenez, G. saacman-VanWertz, P. Misztal, and A. Goldstein. On the implications of aerosol liquid water and phase separation for organic aerosol mass. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, GERMANY, 17: 343-369, (2017).

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).