title: Application of the Extreme Value Distribution to Estimate the Uncertainty of Peak Sound Pressure Levels at the Workplace.
abstract: OBJECTIVE
  The purpose of this article is to develop a method for the statistical inference of the maximum peak sound pressure level and of the associated uncertainty. Both quantities are requested by the EU directive 2003/10/EC for a complete and solid assessment of the noise exposure at the workplace.
  
  
  METHODS
  Based on the characteristics of the sound pressure waveform, it is hypothesized that the distribution of the measured peak sound pressure levels follows the extreme value distribution. The maximum peak level is estimated as the largest member of a finite population following this probability distribution. The associated uncertainty is also discussed, taking into account not only the contribution due to the incomplete sampling but also the contribution due to the finite precision of the instrumentation.
  
  
  RESULTS
  The largest of the set of measured peak levels underestimates the maximum peak sound pressure level. The underestimate can be as large as 4 dB if the number of measurements is limited to 3-4, which is common practice in occupational noise assessment. The extended uncertainty is also quite large (~2.5 dB), with a weak dependence on the sampling details.
  
  
  CONCLUSIONS
  Following the procedure outlined in this article, a reliable comparison between the peak sound pressure levels measured in a workplace and the EU directive action limits is possible. Non-compliance can occur even when the largest of the set of measured peak levels is several dB below such limits.
authors.affiliation: Florence Research Unit, Italian National Workers' Compensation Authority, Via delle Porte Nuove 61, 50144 Florence, Italy p.lenzuni@inail.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Lenzuni
mesh_terms: D000162:Acoustics; D004784:Environmental Monitoring / Q000379:methods*; D005062:European Union; D006317:Hearing Loss, Noise-Induced; D006801:Humans; D015233:Models, Statistical; D009623:Noise, Occupational / Q000009:adverse effects* / Q000331:legislation & jurisprudence; D016273:Occupational Exposure / Q000032:analysis / Q000592:standards; D013016:Sound; D035501:Uncertainty; D017132:Workplace
keywords: noise; occupational risk; peak sound pressure level; uncertainty