What sound level is considered unsafe for human exposure?

The correct choice is associated with sound levels that can pose a significant risk to human hearing health and overall well-being. Sound levels exceeding 90 dBa are recognized as dangerous, particularly after prolonged exposure.

According to the guidelines established by various health and safety organizations, continuous exposure to noise levels at or above this threshold can lead to noise-induced hearing loss, as well as other health effects such as increased stress levels and potential cardiovascular issues. The risk of hearing damage increases with both the intensity of the sound and the duration of exposure.

In contrast, sound levels less than 70 dBa are generally considered safe for human exposure, as they are below the threshold at which hearing protection typically becomes necessary. Levels between 70 dBa and 80 dBa can be problematic over extended periods, but they do not present the immediate risks that levels above 90 dBa do. Sound levels greater than 100 dBa present an even higher risk of hearing damage, but the option focusing on levels greater than 90 dBa is particularly accurate, as it is the standard cutoff used to determine the need for hearing conservation programs in various occupational settings.