Longitudinal study of hearing in children II: Cross‐sectional studies of noise exposure as measured by dosimetry

General Radio and Metrosonics brand portable noise dosimeters were used to record daily average 24‐h log equivalent sound levels [Leq(24)] in 127 children and youths aged 7.0 to 20.0 years (?±S.D. = 14.2±3.5 years). These children were a subset of those participating in a long‐term serial study of hearing in children at the Fels Research Institute. Seventy‐five children had multiple 24‐h recordings; 234 measurements were made in all. The mean Leq(24) was substantial, between 76.7 and 83.8 dB and several children had levels dangerously high, above 90 dB. There were no significant age trends or racial differences for Leq(24) and no significant differences in Leq(24) occurred between tests recorded during the school year (September–May) and those recorded during the summer (June–August). There were, however, small, but significant sex differences; boys had a mean Leq(24) about 2 dB higher than girls. Hearing threshold levels were positively correlated with Leq(24) in girls, but a similar trend was not presen...