This dataset contains organic functional group, organic matter (OM), organic carbon (OC) concentration measurements at five sites in the SEARCH network from 2009-2016.  Spectra from each sample are included, in the format used in these papers.  The sampling sites are urban Birmingham (BHM) and rural Centreville (CTR) in Alabama, urban Jefferson Street, Atlanta (JST) and rural Yorkville (YRK) in Georgia, and rural Outlying Landing Field (OLF) near Pensacola in Florida as well as a co-located site at JST (cJST).  The organic functional groups measured are:  saturated/aliphatic C-H (aCH), carboxylic acid (COOH), oxalate C=O (oxOCO), and non-acid, non-oxalate carbonyl (naCO).  OM mass is calculated as the sum of the organic functional group masses.  Samples were collected for 24-hour from midnight to midnight. OC mass is the sum of the mass of carbon from each functional group.  From 2009-2015, data are available for every third day, and in 2016, daily data are available. 

Teflon filter samples were collected as part of the SEARCH network.  Samples from five SEARCH network sites, and one site co-located with JST (cJST) are used in this study:

1. Centreville, AL (CTR, site number 3): 32.9033 N, -87.2499 W, elevation 141 m a.s.l.
2. Yorkville, GA (YRK, site number 4): 33.9284 N, -85.0454 W, elevation 398 m a.s.l.
3. Jefferson Street, Atlanta, GA (JST, site number 5): 37775 N, -84.4166 W, 293 m a.s.l.
4. Co-located Jefferson Street, Atlanta, GA (cJST, site number 15): 33.7775 N, -84166 W, 293 m a.s.l. 
5. Birmingham, AL (BHM, site number 6): 33.5530, -86.8147 W, 174 m a.s.l.
6. Outlying Landing Field near Pensacola, FL (OLF, site number 7): 30.5500 N, -87.3753 W, elevation 25 m a.s.l.

The functional group data are obtained from FT-IR spectra of particulate matter samples collected on Teflon filters.  The FT-IR spectra are calibrated using laboratory generated standards on Teflon filters containing compounds with each of the functional groups as well as interferents such as ammonium sulfate, ammonium nitrate and water.  All data are reported in mg/m³, and the uncertainties in functional group, OM, and OC concentrations are reported for each sample. Uncertainties are calculated from additive uncertainty (minimum detection limit, MDL) and multiplicative uncertainty (based on co-located sampling uncertainty), as described elsewhere (Hyslop and White, 2009).  Spectra included are infrared absorption at each specified wavenumber (between ~4000 and 1500 cm^-1, in absorbance units). Spectra are raw (neither baseline correction nor derivation was performed).  For more information, refer to the accompanying papers on this work, Boris et al., 2019 and Boris et al., In Preparation.

References

Boris, A. J., Takahama, S., Weakley, A. T., Debus, B. M., Fredrickson, C. D., Esparza-Sanchez, M., Burki, C., Reggente, M., Shaw, S. L., Edgerton, E. S. and Dillner, A. M.: Quantifying organic matter and functional groups in particulate matter filter samples from the southeastern United States – Part 1: Methods, Atmos. Meas. Tech., 12, 1–24, doi:10.5194/amt-2019-144, 2019.

Boris, A. J., Takahama, S., Weakley, A. T., Debus, B. M., Reggente, M., Burki, C., Shaw, S. L., Edgerton, E. S. and Dillner, A. M.: Quantifying organic matter and functional groups in particulate matter filter samples from the southeastern United States – Part II: Trends, Atmos. Meas. Tech., n.d.

Hyslop, N. P. and White, W. H.: Estimating precision using duplicate measurements, J. Air Waste Manag. Assoc., 59(9), 1032–1039, doi:10.3155/1047-3289.59.9.1032, 2009.

Functional group concentrations below MDL have been censored to MDL/2, and samples with three or greater functional group concentrations below MDL were removed from the dataset.  Samples with insufficient flow rates or sampling times were also removed from the dataset.  For more information including the description of all columns/variables in data files, refer to the ReadMe file and to the accompanying paper on the methods of this work, Boris et al., 2019.