HEI Research Report 192, Multicenter Ozone Study in oldEr Subjects (MOSES): Part 1. Effects of Exposure to Low Concentrations of Ozone on Respiratory and Cardiovascular Outcomes, measured a large number of cardiovascular and respiratory endpoints in 87 healthy participants (60 years old on average) who were exposed to 0, 70, or 120 parts per billion ozone for 3 hours while exercising moderately. Although ozone has been documented to have acute and chronic respiratory effects, MOSES was designed to test a question that has been less well understood: whether ozone has short-term cardiovascular effects at present-day ambient levels. The multicenter study was conducted by John Balmes at the University of California–San Francisco, Phil Bromberg at the University of North Carolina–Chapel Hill, and Mark Frampton at the University of Rochester, New York, and their teams and followed rigorous, standardized protocols. All statistical analyses were conducted centrally at the New England Research Institute.