While the A-weighted sound level discounts frequencies not typically sensed by the auditory system, the unweighted sound level–the dB–represents the true noise level, which we also feel is important to report for a few reasons. First, while the lower and higher frequencies discarded when using the dBA may not be sensed by the auditory system, they may still be sensed by other organ systems. Second, according to the World Health Organization, NIGHTTIME sound levels should not exceed 45 dBA. However, there are no guidelines for Unweighted sound levels for either day or night, which are much higher than the dBA. Third, there is a growing body of literature highlighting the effects of lower-frequency noise (which the dBA heavily discards) on negative health.
Do you notice any particular patterns with Unweighted weekday nighttime sound? In which areas of Greater Boston do you notice tend to have higher total sound levels during the weekday nighttime?