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).