Types of Earphones or Headphones that Reduce Background Noise
One style of earphone or headphone isn’t necessarily safer than another. Each device can still be turned up too loud for too long.
Over the Ear Headphones
Headphones that fit all the way around the ear and seal against the head can also reduce background noise levels. These may also allow you to listen safely at lower volume levels.
“Active noise cancellation” earphones or headphones
These types of devices not only seal the ear, but they also use specialized microphones and speakers to eliminate unwanted background noise. These devices eliminate the unwanted sound by reversing the phase of the constant background noise. This allows listeners to choose lower volume settings in noisy places.
People using noise-cancellation earphones listen about 4 dB lower than those without noise-cancellation technology. This is especially useful when listening in noisy environments such as 
an airplane or school bus.
Remember phase? When 2 sounds are 180 degrees out of phase, they can cancel each other out.
Phase is the fraction of a complete wave cycle elapsed as measured from a specified reference point and often expressed as an angle. Sound is cancelled (eliminated) when two sounds are presented at 180 degrees out of phase.