This dataset contains data from the LAMARCK controlled exposure study including DNA methylation assessments done before and 24 hours after each exposure, subclinical health outcomes measures, exposure details, and demographic information on the individual participants in the study. This dataset is not publicly accessible because: EPA cannot release personally identifiable information regarding living individuals, according to the Privacy Act and the Freedom of Information Act (FOIA). This dataset contains information about human research subjects. Because there is potential to identify individual participants and disclose personal information, either alone or in combination with other datasets, individual level data are not appropriate to post for public access. Restricted access may be granted to authorized persons by contacting the party listed. It can be accessed through the following means: The dataset can be accessed by contacting Dr. Cavin Ward-Caviness (ward-caviness.cavin@epa.gov). Format: The data is tabular data containing information on DNA methylation assessment, controlled exposure conditions, and demographics of the LAMARCK participants. DNA methylation age has also been calculated based on the DNA methylation assessment data. This dataset is associated with the following publication: Nwanaji-Enwerem, J., A. Bozack, C. Ward-Caviness, D. Diazsanchez, R. Devlin, M. Bind, and A. Cardenas. Bronchial Cell Epigenetic Aging in a Human Experimental Study of Short-term Diesel and Ozone Exposures. Environmental Epigenetics. Oxford University Press, Cary, NC, USA, 10(1): dvae017, (2024).