For routes up to FL320, what is the ozone concentration limit?

For routes up to FL320, what is the ozone concentration limit?

• A. 0.25 PPM, Sea Volume Equiv. +FL320
• B. 0.1 PPM, Sea Volume Equiv. 3 Hour Interval +FL270
• C. 0.3 PPM, Sea Volume Equiv. +FL360
• D. 0.2 PPM, Sea Volume Equiv. +FL300

Answer: (A)

Ozone exposure limits on flight planning are expressed as a concentration that is adjusted for altitude, so crews can compare the same safety threshold across different air densities. For routes up to FL320, the limit is 0.25 parts per million, expressed as Sea Volume Equivalent and applicable up to and including flight level 320. The Sea Volume Equivalent converts the ozone reading to what it would be at sea level, accounting for thinner air at higher altitudes, which keeps the limit consistent as you climb. The +FL320 part marks the upper boundary of this limit; beyond that altitude, a different threshold would apply. The other options conflict either by using a different ozone value or by tying the limit to an altitude outside the up-to-FL320 range or without the sea-volume adjustment, so they don’t fit the standard for routes up to FL320.

Ozone exposure limits on flight planning are expressed as a concentration that is adjusted for altitude, so crews can compare the same safety threshold across different air densities. For routes up to FL320, the limit is 0.25 parts per million, expressed as Sea Volume Equivalent and applicable up to and including flight level 320. The Sea Volume Equivalent converts the ozone reading to what it would be at sea level, accounting for thinner air at higher altitudes, which keeps the limit consistent as you climb. The +FL320 part marks the upper boundary of this limit; beyond that altitude, a different threshold would apply. The other options conflict either by using a different ozone value or by tying the limit to an altitude outside the up-to-FL320 range or without the sea-volume adjustment, so they don’t fit the standard for routes up to FL320.