i try to find the difference between one blast and hearing loss and a long period of noise and then long years of hearing loss going more and more down after not being in a noise environment anymore. one blast-or long time noise- the difference of losing hearing after noise source disappear

That's a good way to explain what happens. The cochlear, which is the snail shaped organ has thousands of 'hair cells' that pick up sound and transmit it to the auditory nerve, which sends sound to the brain for interpretation. Think of those hair cells like a piano keyboard. When they start to die or malfunction, you miss the sound they were responsible for transmitting. Excess noise can damage those hair cells. They can go slowly or all at once as with a loud blast.

Hearing loss and tinnitus which is also related to those hair cells/cochlea is the most common disability experienced by veterans who have been in combat zones. Some have experienced constant moderate noise, while others have experienced loss due to a single blast near the ear.

That piano keyboard tends to lose sound and pitches in the higher ranges first. That is why most of us with sensorineural hearing loss have more trouble with high pitched voices than with lower pitched voices.