NO2 and O3 data from the DISCOVER-AQ field study measured by the United States EPA. This dataset is associated with the following publication: Long, R., M. Beaver, R. Duvall, J. Szykman, S. Kaushik, K. Kronmiller, M. Wheeler, S. Garvey, and J. Crawford. Evaluation and Comparison of Methods for Measuring Ozone and NO2 Concentrations in Ambient Air during DISCOVER-AQ. EM Magazine. Air and Waste Management Association, Pittsburgh, PA, USA, 1-11, (2016).

We used data from EPA's AQS database and from the Ozone NAAQS review documentation. This dataset is associated with the following publication: Koplitz, S., H. Simon, B. Henderson, J. Liljegren, G. Tonnesen, A. Whitehill, and B. Wells. Changes in ozone chemical sensitivity in the U.S. from 2007 to 2016. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY. American Chemical Society, Washington, DC, USA, 2(3): 206-222, (2021).

We used data from EPA's AQS database and from the Ozone NAAQS review documentation. This dataset is associated with the following publication: Koplitz, S., H. Simon, B. Henderson, J. Liljegren, G. Tonnesen, A. Whitehill, and B. Wells. Changes in ozone chemical sensitivity in the U.S. from 2007 to 2016. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY. American Chemical Society, Washington, DC, USA, 2(3): 206-222, (2021).

Data set contains data collected during the DISCOVER-AQ Mission that support the journal article results. This dataset is associated with the following publication: Duvall , R., R. Long , M. Beaver , K. Kronmillwe, M. Wheeler, J. Szykman , M. Silverman, and J.H. Crawford. Performance Evaluation and Community Application of Low-Cost Sensors for Ozone and Nitrogen Dioxide. Sensors. MDPI AG, Basel, SWITZERLAND, 16(10): 1698, (2016).

This data sets includes data shown in the Figures and Tables in the publication by Zhang et al (2018): https://doi.org/10.5194/acp-2018-498. This dataset is associated with the following publication: Zhang, Y., J.J. West, R. Mathur, J. Xing, C. Hogrefe, S. Roselle, J. Bash, J. Pleim, C. Gan, and D. Wong. Long-term trends in the ambient PM2.5- and O3-related mortality burdens in the United States under emission reductions from 1990 to 2010. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, GERMANY, 18(20): 15003-15016, (2018).

This data sets includes data shown in the Figures and Tables in the publication by Zhang et al (2018): https://doi.org/10.5194/acp-2018-498. This dataset is associated with the following publication: Zhang, Y., J.J. West, R. Mathur, J. Xing, C. Hogrefe, S. Roselle, J. Bash, J. Pleim, C. Gan, and D. Wong. Long-term trends in the ambient PM2.5- and O3-related mortality burdens in the United States under emission reductions from 1990 to 2010. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, GERMANY, 18(20): 15003-15016, (2018).

These data include three-dimensional meteorological (WRF) and air quality (CMAQ) model output for 4-km and 2-km domains covering the San Joaquin Valley (SJV) of California for January and February of 2013. The WRF and CMAQ parameters used in the analysis presented in the research effort are listed in the attached spreadsheet. The WRF/CMAQ data themselves are located on EPA's asm tape archive in the directories below. These data are available upon request from the authors, specifically K. Wyat Appel (appel.wyat@epa.gov). /asm/MOD3EVAL/DISCOVERAQ/SJV/DISCOVERAQ_SJV_4km_CMAQv52_Jul19_CB6_NewEmis /asm/MOD3EVAL/DISCOVERAQ/SJV/output_sf_SJV_2km_CMAQv52_CB6_Jul192017rel_NewEmis. This dataset is associated with the following publication: Choi, S., L. Lok, J. Joiner, N. Krotkov, M. Follette-Cook, W. Swartz, K. Pickering, C. Loughner, K.W. Appel, G. Pfister, P. Saide, R. Cohen, A. Weinheimer, and J. Herman. Assessment of NO2 Observations during DISCOVER-AQ and KORUS-AQ Field Campaigns. Atmospheric Measurement Techniques. Copernicus Publications, Katlenburg-Lindau, GERMANY, 13(5): 2523–2546, (2020).

These data include three-dimensional meteorological (WRF) and air quality (CMAQ) model output for 4-km and 2-km domains covering the San Joaquin Valley (SJV) of California for January and February of 2013. The WRF and CMAQ parameters used in the analysis presented in the research effort are listed in the attached spreadsheet. The WRF/CMAQ data themselves are located on EPA's asm tape archive in the directories below. These data are available upon request from the authors, specifically K. Wyat Appel (appel.wyat@epa.gov). /asm/MOD3EVAL/DISCOVERAQ/SJV/DISCOVERAQ_SJV_4km_CMAQv52_Jul19_CB6_NewEmis /asm/MOD3EVAL/DISCOVERAQ/SJV/output_sf_SJV_2km_CMAQv52_CB6_Jul192017rel_NewEmis. This dataset is associated with the following publication: Choi, S., L. Lok, J. Joiner, N. Krotkov, M. Follette-Cook, W. Swartz, K. Pickering, C. Loughner, K.W. Appel, G. Pfister, P. Saide, R. Cohen, A. Weinheimer, and J. Herman. Assessment of NO2 Observations during DISCOVER-AQ and KORUS-AQ Field Campaigns. Atmospheric Measurement Techniques. Copernicus Publications, Katlenburg-Lindau, GERMANY, 13(5): 2523–2546, (2020).

DISCOVERAQ_Colorado_Ozonesondes_Data contains data collected via ozonesonde launches at the Platteville ground site during the Colorado (Denver) deployment of NASA's Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field study. This data product contains data for only the Colorado deployment, and data collection is complete.Understanding the factors that contribute to near surface pollution is difficult using only satellite-based observations. The incorporation of surface-level measurements from aircraft and ground-based platforms provides the crucial information necessary to validate and expand upon the use of satellites in understanding near surface pollution. DISCOVER-AQ was a four-year campaign conducted in collaboration between NASA Langley Research Center, NASA Goddard Space Flight Center, NASA Ames Research Center, and multiple universities to improve the use of satellites to monitor air quality for public health and environmental benefit. Through targeted airborne and ground-based observations, DISCOVER-AQ enabled more effective use of current and future satellites to diagnose ground level conditions influencing air quality.DISCOVER-AQ employed two NASA aircraft, the P-3B and King Air, with the P-3B completing in-situ spiral profiling of the atmosphere (aerosol properties, meteorological variables, and trace gas species). The King Air conducted both passive and active remote sensing of the atmospheric column extending below the aircraft to the surface. Data from an existing network of surface air quality monitors, AERONET sun photometers, Pandora UV/vis spectrometers and model simulations were also collected. Further, DISCOVER-AQ employed many surface monitoring sites, with measurements being made on the ground, in conjunction with the aircraft. The B200 and P-3B conducted flights in Baltimore-Washington, D.C. in 2011, Houston, TX in 2013, San Joaquin Valley, CA in 2013, and Denver, CO in 2014. These regions were targeted due to being in violation of the National Ambient Air Quality Standards (NAAQS).The first objective of DISCOVER-AQ was to determine and investigate correlations between surface measurements and satellite column observations for the trace gases ozone (O3), nitrogen dioxide (NO2), and formaldehyde (CH2O) to understand how satellite column observations can diagnose surface conditions. DISCOVER-AQ also had the objective of using surface-level measurements to understand how satellites measure diurnal variability and to understand what factors control diurnal variability. Lastly, DISCOVER-AQ aimed to explore horizontal scales of variability, such as regions with steep gradients and urban plumes.