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4.8 Noise <br />nighttime, respectively. The logarithmic effect of these additions is that a 60 dBA 24 hour Leg <br />would result in a measurement of 66.7 dBA CNEL. <br />■ L,,, the minimum instantaneous noise level experienced during a given period of time. <br />■ L„ „ the maximum instantaneous noise level experienced during a given period of time. <br />TableRepresentative <br />Common Outdoor Activities <br />Nofse Level (dBA) <br />Environmental Noise Levels <br />Common Indoor Activities <br />Power Saw <br />—110— <br />Rock Band <br />Jet Fly -over at 100 feet <br />Crying Baby <br />Subway <br />—100— <br />Gas Lawnmower at 3 feet <br />Tractor <br />—g0— <br />Food Blender at 3 feet <br />Diesel Truck going 50 mph at 50 feet <br />—80— <br />Garbage Disposal at 3 feet <br />Noisy Urban Area during Daytime <br />Gas Lawnmower at 100 feet <br />—70— <br />Vacuum Cleaner at 10 feet <br />Commercial Area <br />Normal Speech at 3 feet <br />Heavy Traffic at 300 feet <br />—60— <br />Sewing Machine <br />Air Conditioner <br />Large Business Office <br />Quiet Urban Area during Daytime <br />—50— <br />Dishwasher in Next Room <br />Refrigerator <br />Quiet Urban Area during Nighttime <br />—40— <br />Theater, Large Conference Room (background) <br />Quiet Suburban Area during Nighttime <br />—30— <br />Library <br />Quiet Rural Area during Nighttime <br />Bedroom at Night, Concert Hall (background) <br />—20— <br />BroadcasNRecording Studio <br />—10— <br />Lowest Threshold of Human Hearing <br />—0— <br />Lowest Threshold of Human Hearing <br />SOURCE: League of the Hard of Hearing 2006 <br />Noise environments and consequences of human activities are usually well represented by median noise <br />levels during the day or night, or over a 24-hour period. Environmental noise levels are generally <br />considered low when the CNEL is below 60 dBA, moderate in the 60 to 70 dBA range, and high above <br />70 dBA. Examples of low daytime levels are isolated, natural settings that can provide noise levels as low <br />as 20 dBA and quiet, suburban, residential streets that can provide noise levels around 40 dBA. Noise <br />levels above 45 dBA at night can disrupt sleep. Examples of moderate -level noise environments are <br />City of Santa Ana Transit Zoning Code (SD 84A and SD 84B) EIR 4.8-3 <br />