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).

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).

These data are a part of Multi-Decadal Sulfur Dioxide (SO2) Climatology from Satellite Instruments (MEaSUREs-12-0022 project). Version 2 of the global catalogue of emissions from large SO2 point sources combines data from the Ozone Monitoring Instrument (OMI) on NASA's EOS Aura spacecraft, the Ozone Mapping and Profiler Suite (OMPS) on the NASA-NOAA Suomi National Polar-orbiting Partnership (SNPP), and the TROPOspheric Monitoring Instrument (TROPOMI) on the ESA/Copernicus Sentinel-5 Precursor (S-5P) spacecraft. The catalogue MSAQSO2L4 file contains the site coordinates, source type, country, source name, annual SO2 emissions, annual emission uncertainties, and the number of satellite pixels in the fitting area for three satellite instruments as well as for their weighted average. The emission estimates are based on operational version 2 OMI and OMPS Principal Component Analysis (PCA) retrieval algorithm SO2 slant column density (SCD) data (Li et al., 2020) as well as on new TROPOMI Covariance-Based Retrieval Algorithm (COBRA) SCD data (Theys et al., 2021). A single time-independent site-specific Air-Mass Factor (AMF) value for each site was calculated (McLinden et al., 2014) and applied consistently to each satellite SCD dataset to derive SO2 vertical column densities (VCDs=SCDs/AMFs). The emission estimate method is based on a fit of satellite VCDs to an empirical plume model developed to describe the SO2 spatial distribution near emission point sources. The plume model assumes that the SO2 concentrations emitted from a point source decline exponentially with distance and that they are affected by turbulent diffusion that can be described by a two-dimensional (2D) exponentially modified Gaussian function. The total SO2 mass is derived from the fit and the annual emission rate is calculated as the ratio between the total mass and the prescribed SO2 lifetime.

This file describes the dataset used in the following article: Nolte, C. G., Spero, T. L., Bowden, J. H., Sarofim, M. C., Martinich, J., Mallard, M. S., Fann, N., "Regional Temperature-Ozone Relationships Across the U.S. Under Multiple Climate and Emissions Scenarios," 2020. MODEL VERSION AND CONFIGURATION The Community Multiscale Air Quality (CMAQ) model was used. The model is open source and can be freely downloaded at http://github.com/USEPA/CMAQ. The specific code version used in this study was based on a pre-release version of CMAQ 5.3, with minor modifications to accommodate the USGS28 land-use scheme used in WRF. The model source code is included in the "src" directory. The meteorological input data for CMAQ were derived from outputs of the Community Earth System Model (CESM) and the Coupled Model version 3 (CM3) following Representative Concentration Pathway (RCP) 8.5, which represents a relatively high warming scenario. The CESM and CM3 fields were downscaled to 36-km grid cells over North America using the Weather Research and Forecasting model. The downscaling and air quality modeling procedure are described in the associated manuscript (Nolte et al., submitted manuscript, 2020) and references therein. CMAQ simulations were conducted using the meteorology downscaled from the two climate models and using two different sets of anthropogenic emissions: the 2011 National Emission Inventory and a 2040 projection developed for analysis of the Heavy Duty Greenhouse Gas Rule. This 2040 projection represents significant reductions relative to present-day of pollutant emissions, including nitrogen oxides (NOx), sulfur dioxide, and volatile organic compounds (VOCs). See U.S. EPA (2016) for further information on the anthropogenic emissions. Climate-sensitive VOCs emitted from vegetation, e.g., isoprene, were modeled within CMAQ using the downscaled meteorological projections from WRF. CMAQ was used to simulate air pollutant concentrations over the continental United States using grid cells with 36km x 36km horizontal spacing, with the height of the lowest model layer around 38 m. Further details on the model configuration and input data are described in the manuscript. Figures used in this paper were prepared using version 3.6.1 of the R programming language. R is open source, and can be downloaded at www.r-project.org. The R scripts are labeled according to their figure number, and reference all data needed to generate the figures, which are located in the "figs" folder. This dataset is associated with the following publication: Nolte, C., T. Spero, J. Bowden, M. Sarofim, J. Martinich, and M. Mallard. Regional Temperature-Ozone Relationships Across the U.S. Under Multiple Climate and Emissions Scenarios. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION. Air & Waste Management Association, Pittsburgh, PA, USA, 71(10): 1251-1264, (2021).

This file describes the dataset used in the following article: Nolte, C. G., Spero, T. L., Bowden, J. H., Sarofim, M. C., Martinich, J., Mallard, M. S., Fann, N., "Regional Temperature-Ozone Relationships Across the U.S. Under Multiple Climate and Emissions Scenarios," 2020. MODEL VERSION AND CONFIGURATION The Community Multiscale Air Quality (CMAQ) model was used. The model is open source and can be freely downloaded at http://github.com/USEPA/CMAQ. The specific code version used in this study was based on a pre-release version of CMAQ 5.3, with minor modifications to accommodate the USGS28 land-use scheme used in WRF. The model source code is included in the "src" directory. The meteorological input data for CMAQ were derived from outputs of the Community Earth System Model (CESM) and the Coupled Model version 3 (CM3) following Representative Concentration Pathway (RCP) 8.5, which represents a relatively high warming scenario. The CESM and CM3 fields were downscaled to 36-km grid cells over North America using the Weather Research and Forecasting model. The downscaling and air quality modeling procedure are described in the associated manuscript (Nolte et al., submitted manuscript, 2020) and references therein. CMAQ simulations were conducted using the meteorology downscaled from the two climate models and using two different sets of anthropogenic emissions: the 2011 National Emission Inventory and a 2040 projection developed for analysis of the Heavy Duty Greenhouse Gas Rule. This 2040 projection represents significant reductions relative to present-day of pollutant emissions, including nitrogen oxides (NOx), sulfur dioxide, and volatile organic compounds (VOCs). See U.S. EPA (2016) for further information on the anthropogenic emissions. Climate-sensitive VOCs emitted from vegetation, e.g., isoprene, were modeled within CMAQ using the downscaled meteorological projections from WRF. CMAQ was used to simulate air pollutant concentrations over the continental United States using grid cells with 36km x 36km horizontal spacing, with the height of the lowest model layer around 38 m. Further details on the model configuration and input data are described in the manuscript. Figures used in this paper were prepared using version 3.6.1 of the R programming language. R is open source, and can be downloaded at www.r-project.org. The R scripts are labeled according to their figure number, and reference all data needed to generate the figures, which are located in the "figs" folder. This dataset is associated with the following publication: Nolte, C., T. Spero, J. Bowden, M. Sarofim, J. Martinich, and M. Mallard. Regional Temperature-Ozone Relationships Across the U.S. Under Multiple Climate and Emissions Scenarios. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION. Air & Waste Management Association, Pittsburgh, PA, USA, 71(10): 1251-1264, (2021).

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).

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.

The NARSTO_SOS_SC_UPSTATE_PM25_COMPOSITION data were collected during July 2001 and January of 2002 to elucidate the seasonal variability of the aerosols. Samples were collected at a rural location in South Carolina, beginning and ending at midnight in order to associate each sampling event with a calendar day. In all, 40 samples per month were collected (including blanks).The purpose of the study was to determine experimentally the concentration and chemical composition of fine particulate matter (PM2.5, particles with a diameter less than 2.5 um) in South Carolina. The collection of PM2.5 samples on Teflon filters was carried out using a cyclone-based system. Ion chromatography analysis for anions and cations was performed, as well as x-ray fluorescence (XRF) analysis for crustal metals. PM2.5 samples on quartz filters were also collected in order to determine the organic and elemental carbon (EC/OC) particle concentration.The average concentration for PM2.5 during July of 2001 was 20.85 mg/m3. The major components of the aerosol were organic compounds (38.5%) and sulfates (34.7%). During January of 2002, the average concentration for PM2.5 was 9.4 mg/m3. Again, the major components of the aerosol were organic compounds (64.1%) and sulfates (21.9%).NARSTO (formerly North American Research Strategy for Tropospheric Ozone) is a public/private partnership, whose membership spans government, the utilities, industry, and academe throughout Mexico, the United States, and Canada. The primary mission is 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 available.

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).