RES 211231 Exhibit A - Laserfiche WebLink

Environmental Checklist and City of Pleasanton–10x Genomics Project Environmental Evaluation Initial Study/Mitigated Negative Declaration 110 FirstCarbon Solutions Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480024/ISMND/wp/21480024 10x Genomics Project Full Screencheck ISMND.docx generate approximately 60 dBA to 70 dBA Lmax at 50 feet. Conversation between two persons at a distance of 3 to 5 feet apart would generate a noise level of 60 dBA Leq at 5 feet, or approximately 40 dBA Leq as measured at 50 feet. In a reasonable worst-case scenario, assuming one parking movement per parking stall within an hour, parking lot activities could result in intermittent noise levels ranging up to 43 dBA Leq as measured at the property boundary of the nearest residential land use to the parking lot, the multi-family residential receptor southwest of the project site. All operational noise level calculations are provided in Appendix H. It should be noted that these calculations and noise impact conclusions would also apply to the proposed interim parking lot that would be located on the southern portion of the project site. Thus, noise from these activities would not exceed the City’s most restrictive noise performance standard (the standard for nighttime hours) of 65 dBA Leq as measured at the property boundary of the nearest residential land use. Therefore, noise impacts from operational parking lot activity would not result in a substantial permanent increase in ambient noise levels in excess of any of the noise performance thresholds and would be less than significant. Mechanical Equipment Operations The proposed project would not utilize ventilation units larger or noisier than standard commercial- grade ventilation systems; therefore, a reference noise level for typical rooftop mechanical ventilation systems was used. Noise levels from typical rooftop mechanical ventilation equipment are anticipated to range up to approximately 60 dBA Leq at a distance of 25 feet. The mechanical ventilation equipment would be setback at least 10 feet from the edge of the proposed building’s rooftop. Thus, rooftop mechanical ventilation systems could be located as close as 225 feet from the property line of the nearest noise sensitive receptor, which are the multi-family residences on Stoneridge Mall Road east of the project site. Based on distance attenuation, noise generated by rooftop mechanical ventilation equipment would attenuate to approximately 41 dBA Leq as measured at the property boundary of the nearest residential land use. All operational noise level calculations are provided in Appendix H. Thus, noise from mechanical equipment operations would not exceed the City’s most restrictive noise performance standard (the standard for nighttime hours) of 65 dBA Leq as measured at the property boundary of the nearest residential land use. Truck Loading Activities Noise would be generated by loading and unloading activities at the loading zones of the proposed commercial buildings. Typical noise levels from truck loading and unloading activity can range from 70 dBA to 80 dBA Lmax as measured at 50 feet. A reasonable worst-case scenario assumes that multiple trucks at the nearest loading bays to the nearest off-site receptor could produce simultaneous loading and unloading activities within a single hour. The proposed loading areas are positioned such that noise generated by loading and unloading activities would be shielded by the intervening proposed buildings. This shielding would provide an expected minimum 10 dBA reduction in truck loading noise levels. The nearest residential property line is located approximately 350 feet from the nearest proposed loading area. Therefore, due to distance attenuation and shielding reduction, truck loading and unloading activities would result in reasonable