Section 675.008 - Action Air Levels for Carbon Monoxide and Nitrogen Dioxide(A) Air levels to be referred to as correction air levels shall be a single air sample exceeding 30 parts per million (ppm) for carbon monoxide and of 0.5 ppm for nitrogen dioxide.(B) Air levels to be referred to as notification air levels shall be a single air sample exceeding 60 parts per million (ppm) or six consecutive air samples which exceed 30 parts per million (ppm) for carbon monoxide and a single air sample exceeding one part per million (ppm) or six consecutive samples which exceed 0.5 parts per million (ppm) for nitrogen dioxide.(C) Air levels to be referred to as evacuation air levels shall be a single air sample exceeding 125 parts per million (ppm) for carbon monoxide and two ppm for nitrogen dioxide.