Squawk,
I'm testing a sound meter with full octave band analysis for work at the moment so a couple of hours running the meter in the cockpit sounds like a good experiment. However, the results will only tell the unprotected sound levels in the cockpit but knowing the Noise Reduction Rating of the headset will let us calculate the approximate exposure level at the ear.
It would help if I knew exactly which make and model of headset you are using as all models have differing NRRs.
The bottom line though is that no long term exposure to noise is good for you. Saying that, the NRR of the headset coupled with the relatively small amount of daily exposure should provide an adequate amount of protection to prevent long term damage.
But, as with all things medical, if you ever have any concerns, get yourself off to your GP and request an audiogram.
Best Regards,
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