The mosquito ringtone is a really high-pitched whine that most people past their mid 20s can’t hear any more due to natural progressive hearing loss. Some malls broadcast it outside the building to keep teens from hanging out around the shops- the sound annoys the teens but the average adult shopper can’t hear it. Teens got the last laugh on those old adults by using the sound as a celphone ringtone so they could hear incoming text messages in class and outwit their older teachers.
I’m no teen, but I can still hear the mosquito tone. I perceive it more as an awareness of an unpleasant feeling than an actual sound, though, if that makes any sense. Kind of like when people at work leave televisions on and the buzzing CTR monitor noise makes me go insane. You can test your own hearing here. The mosquito tone is at 17hz. This should be ok to do at work- it’s just a high, electronic sustained beep that’s not very loud, and if any of your coworkers notice it, they won’t be mad for long when you tell them they basically have the eardrums of a pre-teen.