This news article from Koin.com on protecting your hearing from fireworks noise, (actually published for the 4th of July weekend, I’m late, I know) details inaccurate warnings about hearing loss and it just frustrates me when I see that. Statements like this:
Sounds at or above 85 decibels could cause hearing loss. The farther away you get, the lower the decibel level. Some fireworks displays reach 130 decibels.
“85 decibels”, or rather 85 dBA (decibels A-weighted) is what’s commonly cited as a limit for workers before they’re over their exposure limit for the day. Noise exposure has a time AND level limit. It is based on an 8-hour cumulative exposure over a workday, and not as a single instantaneous level to be exceeded. You can be exposed to higher noise levels over a shorter cumulative time, for example, 88 dBA over 4 hours or 91 dBA over 2 hours, before the noise is expected to affect your hearing. By cumulative, I mean that you can be exposed to, say, 91 dBA level of noise for short 10 min time periods but if they add up to 2 hours of time total in a day, you risk hearing damage. So as a statement, the quote above is plain wrong.
As for the “130 decibels” statement, yes fireworks can get that loud, but it also should be qualified with a distance – sound pressure levels decay with distance, and without knowing that, you’re lost. (They should also mention whether the level is A-weighted or not.) A firecracker bang with a sound pressure level of 130 dBA at 1ft is very very different from 130 dBA at 10 ft.