title: MP3 player listening sound pressure levels among 10 to 17 year old students.
abstract: Using a manikin, equivalent free-field sound pressure level measurements were made from the portable digital audio players of 219 subjects, aged 10 to 17 years (93 males) at their typical and "worst-case" volume levels. Measurements were made in different classrooms with background sound pressure levels between 40 and 52 dBA. After correction for the transfer function of the ear, the median equivalent free field sound pressure levels and interquartile ranges (IQR) at typical and worst-case volume settings were 68 dBA (IQR = 15) and 76 dBA (IQR = 19), respectively. Self-reported mean daily use ranged from 0.014 to 12 h. When typical sound pressure levels were considered in combination with the average daily duration of use, the median noise exposure level, Lex, was 56 dBA (IQR = 18) and 3.2% of subjects were estimated to exceed the most protective occupational noise exposure level limit in Canada, i.e., 85 dBA Lex. Under worst-case listening conditions, 77.6% of the sample was estimated to listen to their device at combinations of sound pressure levels and average daily durations for which there is no known risk of permanent noise-induced hearing loss, i.e., ≤  75 dBA Lex. Sources and magnitudes of measurement uncertainties are also discussed.
authors.affiliation: Consumer and Clinical Radiation Protection Bureau, Health Canada, Ottawa, Ontario K1A 1C1, Canada. Stephen.keith@hc-sc.gc.ca
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Keith
authors.forename: David S
authors.initials: DS
authors.lastname: Michaud
authors.forename: Katya
authors.initials: K
authors.lastname: Feder
authors.forename: Ifaz
authors.initials: I
authors.lastname: Haider
authors.forename: Leonora
authors.initials: L
authors.lastname: Marro
authors.forename: Emma
authors.initials: E
authors.lastname: Thompson
authors.forename: Andre M
authors.initials: AM
authors.lastname: Marcoux
mesh_terms: D000293:Adolescent; D000367:Age Factors; D016009:Chi-Square Distribution; D002648:Child; D005260:Female; D006317:Hearing Loss, Noise-Induced / Q000209:etiology; D006801:Humans; D055539:MP3-Player; D008297:Male; D008348:Manikins; D009146:Music; D011312:Pressure; D018570:Risk Assessment; D012307:Risk Factors; D013016:Sound / Q000009:adverse effects; D013334:Students; D011795:Surveys and Questionnaires; D013997:Time Factors; D035501:Uncertainty