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4.5 Noise <br /> tr <br /> • Expose people residing or working in the project area to excessive noise levels if the <br /> i. project is located within an area covered by an airport land use plan, or where such plan has <br /> not been adopted, within two miles of a public airport or public use airport. <br /> • Expose people residing or working in the project area to excessive noise levels if the <br /> project is located in the vicinity of a private airstrip. <br /> • Expose persons to or generate of excessive ground-bome vibration or ground-borne noise <br /> levels. <br /> The significance of project-related noise impacts can be determined by comparing estimated <br /> project-related noise levels to existing no-project noise levels. An increase of at least 3 dBA is <br /> usually required before most people will perceive a change in noise levels, and an increase of <br /> 5 dBA is required before the change will be clearly noticeable. A common practice has been to <br /> assume that minimally perceptible to clearly noticeable increases of 3 to 5 dB represent a <br /> significant increase in ambient noise levels. A sliding scale is commonly used to identify the <br /> `. <br /> significance of noise increases, allowing greater increases at lower absolute sound levels than at <br /> higher sound levels. This approach is based on research that relates changes in noise to the <br /> percentage of individuals that would be highly annoyed by the change (FICON, 1992). Thus,the <br /> significance criteria for changes in noise from project operations are as follows: <br /> 1. A 3 dBA DNL increase in noise as a result of project operations if the resulting level <br /> exceeds the"normally acceptable range"for the land use(65 dBA DNL or less for <br /> residential development). <br /> 2. A 5 dBA DNL increase in noise as a result of project operations if the resulting level is <br /> within the"normally acceptable range"for the land use. <br /> 3. A 3 dBA increase in the hourly Leq noise level as a result of stationary noise sources <br /> associated with the project if the resulting noise level exceeds the hourly standard of <br /> ` 50 dBA Leq during daytime hours (7:00 AM to 10:00 PM)or 45 dBA Lw during nighttime <br /> hours (10:00 PM to 7:00 AM) at an off-site outdoor activity area. <br /> 4. A 5 dBA increase in the hourly L noise level as a result of stationary noise sources <br /> associated with the project if the resulting level is below the hourly standard of 50 dBA <br /> L during daytime hours (7:00 AM to 10:00 PM)or 45 dBA Leq during nighttime hours <br /> ` (1%:00 PM to 7:00 AM) in an outdoor activity area. <br /> 5. The proposed project would introduce stationary noise sources that would result in <br /> maximum noise levels in excess of the San Joaquin County Development Title standard <br /> of 70 dBA L during daytime hours(7:00 AM to 10:00 PM)or 65 dBA L during <br /> nighttime hours (10:00 PM to 7:00 AM) at an off-site outdoor activity area. <br /> The MSHA 1999 noise standards would apply to the project and are assumed to provide hearing <br /> protection for the miners. Occupational noise levels will not be further discussed in the impacts <br /> section of this chapter. <br /> RMC Pacific Vemalis Quarry Mining and Reclamation Project -11 ESA/203015 <br /> Draft Environmental Impact Report May 2006 <br />