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CRITERIA FOR ACCEPTABLE NOISE EXPOSURE The San Joaquin County Noise Ordinance, (Chapter 16, Section 9-3800) states that no sound level shall exceed 65 dB Ldn at the property line of properties which abut areas either developed residential, zoned residential, or shown for residential use on the General Plan. The 65 dB Ldn standard would also apply to the property lines of parks,schools,hospitals,and rest homes. For uses which are not particularly noise sensitive, such as C-M,R-M,M-1 and M-2 zones,the sound level shall not exceed 75 dB Ldn at the property line. Of greater concern for this project than the property line 24-hour average noise level standard,is the degree by which noise levels associated with early morning/nighttime operations of the DSS quarry would exceed existing early morning/nighttime noise levels at the nearest residences. That is,the nearest neighbors will likely respond to noise generated during early morning/nighttime mining and processing activities based how much louder those activities are outside their bedroom windows than current early morning/nighttime background noise levels without the DSS operations. As noted previously, the average noise levels measured during early morning/nighttime hours at Sites A and B on Figure 1 were 44 and 51 dB,respectively. Therefore,provided the projected early morning/nighttime noise emissions of the DSS quarry do not exceed that existing background noise level of 45 dB Leq at the nearest residences, adverse noise impacts associated with early morning /nighttime DSS operations are not anticipated. CURRENT DSS FACILITY NOISE GENERATION To quantify the current noise emissions of the DSS quarry project, Bollard & Brennan, Inc. conducted a series of short-term noise level measurements at locations surrounding the existing processing equipment and mining site. That data was supplemented with noise monitoring conducted near the southern facility property line. The noise measurements were conducted on February 21,2002 using a Larson Davis Laboratories (LDL)Model 824 precision integrating sound level meter. The meter was calibrated before and after use with an LDL Model CA200 acoustical calibrator to ensure the accuracy of the measurements. The equipment used meets all pertinent specifications of the American National Standards Institute for Type 1 sound level meters (ANSI S1.4). Weather conditions present during the noise survey consisted of mild temperatures (approximately 60 degrees Fahrenheit), calm to lightwinds, and partially cloudy skies. The results of the ambient noise level survey indicate that the noise level projections contained in the 1997 project EIR were reasonably accurate. Specifically, noise generated by the processing equipment was measured at 75 to 80 dB Leq at a distance of approximately 100 feet from that equipment,and mining related noise was measured at 65 dB Leq at a distance of 100 feet from those operations (with self-elevating"belly" scrapers operating). Environmental Noise Evaluation Proposed DSS Quarry Rescheduled Hours of Operation Page 3