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3f DraftfALUCPf CompatibilitliFactohlapsf andf Policiesf <br /> 9.A. - Page 70 <br /> 3.2.2 Noise <br /> Noise generated by the operation of aircraft is one of the primary factors that drives land use <br /> compatibility planning.Aircraft noise is generally the most recognizable issues for people living <br /> and working in the vicinity of an airport, and depending on the size of the airport and the types of <br /> operations it accommodates,the geographic extent to which aircraft noise can be experienced is <br /> potentially great. <br /> Aircraft noise contours included in this ALUCP white paper were calculated using the Integrated <br /> Noise Model(INM),Version 7.0d. INM 7.0d is the FAA-approved,industry-accepted, state-of- <br /> the-art tool for determining the total effect of aircraft noise exposure at and around airports. The <br /> INM has been the FAA's standard tool for determining the predicted noise impact in the vicinity <br /> of airports since 1978, and is recognized by the State of California as the appropriate tool for <br /> aircraft noise assessments. <br /> CNEL is the cumulative noise descriptor required for aircraft noise analyses in the State of <br /> California. CNEL is used to describe cumulative noise exposure for an annual-average day of <br /> aircraft operations. CNEL is calculated by mathematically combining the number of single events <br /> that occur during a 24-hour day with how loud the events were and what time of day they <br /> occurred. CNEL includes penalties applied to noise events occurring after 7:00 p.m. and before <br /> 7:00 a.m.,when noise is considered more intrusive. The penalized time period is further <br /> subdivided into evening(7:00 p.m. through 9:59 p.m.)and nighttime (10:00 p.m. to 6:59 a.m.). <br /> CNEL treats every evening operation as though it were three and every night as though it were <br /> ten. This"weighting"adds a 4.77 dB penalty during the evening hours and a 10 dB penalty <br /> during the nighttime hours. <br /> Noise contours presented in this ALUCP white paper depict noise exposure in terms of CNEL. <br /> AircrafthNoise vContours4or.6an .Carlos Airports <br /> Existing Conditions(2013)aircraft noise contours prepared in support of the ALUCP update are <br /> presented on Exhibito3-1. 20-year future conditions (2035)noise contours are presented on <br /> Exhibitu3-2.Areas exposed to aircraft noise levels of CNEL 60, 65, 70, and 75 dB are shown on <br /> both exhibits. For the most part, areas exposed to aircraft noise levels of CNEL 60 and higher are <br /> owned by San Mateo County(the airport proprietor)or are undeveloped. Land use compatibility <br /> policies specific to noise (described below) apply to the noise zones depicted on Exhibit 3-2. <br /> SanfCarlosfAirportV 3-5 ESAfAirportsf/130753f <br /> ALUCPf W hitef Pape/ Junef2014f <br />