For routes with a 3-hour interval up to FL270, what is the ozone concentration limit?

For routes with a 3-hour interval up to FL270, what is the ozone concentration limit?

• A. 0.1 PPM, Sea Volume Equiv. 3 Hour Interval +FL270
• B. 0.25 PPM, Sea Volume Equiv. +FL320
• C. 0.3 PPM, Sea Volume Equiv. +FL270
• D. 0.05 PPM, Sea Volume Equiv. +FL250

Answer: (A)

Exposure to ozone during flight is limited based on how long you’re exposed and at what altitude. For planning routes in three-hour blocks up to FL270, the allowable ozone level is 0.1 ppm when expressed as a sea-level equivalent. The Sea Volume Equiv. concept translates the concentration to a sea-level reference so you have a single limit across this altitude band, and the +FL270 indicates the limit applies up to flight level 270. That combination—0.1 ppm with Sea Volume Equiv. for a 3-hour interval up to FL270—is the applicable limit in this scenario. The other values correspond to different altitude bands or time windows and aren’t applicable here. If higher ozone is encountered, routes would be adjusted or ozone mitigation measures would be used, but the stated limit remains 0.1 ppm in this case.

Exposure to ozone during flight is limited based on how long you’re exposed and at what altitude. For planning routes in three-hour blocks up to FL270, the allowable ozone level is 0.1 ppm when expressed as a sea-level equivalent. The Sea Volume Equiv. concept translates the concentration to a sea-level reference so you have a single limit across this altitude band, and the +FL270 indicates the limit applies up to flight level 270. That combination—0.1 ppm with Sea Volume Equiv. for a 3-hour interval up to FL270—is the applicable limit in this scenario. The other values correspond to different altitude bands or time windows and aren’t applicable here. If higher ozone is encountered, routes would be adjusted or ozone mitigation measures would be used, but the stated limit remains 0.1 ppm in this case.