How children are more sensitive to noise

While hearing loss can affect people at all ages, and is particularly common among the elderly, children require special protection against damage from excessive noise and other aural ailments. Children’s ears are sensitive, with high susceptibility to loud noises (and infection, orotitis). The main reason for this is anatomical: children have both smaller ear canals and thinner skulls, which make them more vulnerable to loud noise.
Photo from All Ear Plugs 
Babies and young children also tend to have better and more sensitive hearing than adults do, as they do not have the lifetime of exposure to noise, and nor have they experienced the more gradual diminution of hearing that naturally occurs with age. For adults, noise of up to 85 decibels is generally considered safe, according to the United States Occupational Safety and Health Administration; but for infants, that level of volume can be too loud.
Children with especially sensitive ears, also called sensitive hearing or hyperacusis, may find loud noises -- even more ordinary ones, such as that of a washing machine or vacuum -- to be intolerable.Furthermore, babies and young children may not have the choice that adults have to avoid loud noise exposure.
If a baby is placed near loud noise, for example, it doesn’t have the choice to simply move away the way that adults do, even if the sound becomes uncomfortable. Because babies and children are young, vulnerable and developing, ear and hearing damage from loud noise exposure can be permanent.
For all these reasons, vigilance is a must in protecting young children from noise damage. Keep your child away from loud noises, and do not allow young children to use earbuds or normal headphones. Music or sound emanating at a safe volume is ok, along with decibel safe, noise canceling headphones. Earmuffs can also be useful as safeguards against loud noise.