https://techcrunch.com/2019/06/04/apples-new-health-feature-tracks-unsafe-headphone-volumes/

According to recent numbers from the World Health Organization, roughly half of people aged 12-35 are at risk for hearing loss. That’s due in no small part to explosive growth in “personal listening devices” like smartphones. Young people are cranking up the volume on their headphones and could be doing irreparable damage to their hearing in the process.

One of the health features Apple didn’t get around to discussing on stage yesterday tracks headphone volume levels over time. The feature, which available as part of the Health app, is able to track listening levels on calibrated and MFi headphones (including AirPods, Beats and the like). That information will be logged as either “OK” or “Loud” based on guidance from the W.H.O.