3 rd Quarter 216 Report Fly Quiet Program Chicago O Hare International Airport Visit the O Hare Noise Webpage on the Internet at www.flychicago.com/ordnoise
3 rd Quarter 216 Report Background On June 17, 1997, the City of Chicago announced that airlines operating at O Hare International Airport had agreed to use designated noise abatement flight procedures in accordance with the Fly Quiet Program. The Fly Quiet Program was implemented in an effort to further reduce the impacts of aircraft noise on the surrounding neighborhoods. The Fly Quiet Program is a voluntary program that encourages pilots and air traffic controllers to use designated nighttime preferential runways and flight tracks developed by the Chicago Department of Aviation in cooperation with the O'Hare Noise Compatibility Commission, the airlines, and the air traffic controllers. These preferred routes direct aircraft over less-populated areas, such as forest preserves, highways, as well as commercial and industrial areas. As part of the Fly Quiet Program, the Chicago Department of Aviation prepares a Quarterly Fly Quiet Report. This report is shared with Chicago Department of Aviation officials, the O'Hare Noise Compatibility Commission, the airlines, and the general public. The Fly Quiet Report contains detailed information regarding nighttime runway use, flight operations, flight tracks, and noise complaints and 24-hour tracking of ground run-ups. The data presented in this report is compiled from the Airport Noise Management System (ANMS) and airport operation logs. Operations O Hare has seven runways that are all utilized at different times depending on a number of conditions including weather, airfield pavement and construction activities and air traffic demand. The Nighttime Runway Use Report compares the average percentage of use for each runway during the current quarter with the previous quarter as well as with the 12-month average. The percentage of use for departures and arrivals is shown graphically for each runway. This data is presented for all aircraft types during nighttime hours of 1: p.m. to 7: a.m. The Nighttime Hourly Operations Report compares the arrivals and departures by hour to the current quarter with the previous quarter as well as with the 12- month average. Percentage is a ratio whereas a percentage point is the difference between two percentages. Highlights for 3Q 216 include: Departures Arrivals Most used nighttime departure runway: 28R 27% Most used nighttime arrival runway: 27L 26% 22L night departures increased by 6pp from 2Q 216 22R night arrivals increased by 8pp from 2Q 216 9R night departures decreased by 7pp from 2Q 216 1L night arrivals decreased by 6pp from 2Q 216 pp = Percentage Points Nighttime operations represent 11% of the overall daily operations Arrival Summary A summary of nighttime arrivals is provided for the two most-used arrival runways (28C and 27L); the airline summary is also compared to the data from the same quarter of the previous year. Preferential Flight Tracks As part of the Fly Quiet Program, the Chicago Department of Aviation worked with the O'Hare Noise Compatibility Commission, the airlines, and the air traffic controllers to identify preferred runways and flight Chicago Department of Aviation Page 1 3rd Quarter 216
tracks for nighttime operations at O Hare. The preferred routes direct aircraft over less-populated areas in an effort to limit the effects of noise on the surrounding communities. Adherence to nighttime departure preferential flight tracks is measured by the ANMS. A detailed airline deviation summary is provided for the two most-used departure runways (32L and 28R); the airline deviation is also compared to the data from the same quarter of the previous year. An average deviation graphic and table is provided for all runways. The Nighttime Flight Track Report measures deviation (in nautical miles) from the preferred flight tracks and is divided into three categories: less than.5 miles between.5 and 1. miles greater than 1. miles Noise Complaints The Chicago Department of Aviation maintains a toll-free O Hare noise hotline (1-8-435-9569) and an on-line service at www.flychicago.com/ordnoise for citizens to express their concerns about particular incidents or about aircraft noise levels in general. The Nighttime Noise Complaint Report summarizes the number of complaints received and where the complainants were located. The tabular report lists the number of complaints by community as well as the number of individual complainants. The graph at the bottom of the page illustrates the nature of the complaints during the current quarter. Complaints include all complaints made within the State of Illinois to the O Hare Noise Hotline toll-free number or on-line feature. Ground Run-ups Ground run-ups are aircraft engine tests that are performed to ensure that the engines are working properly after maintenance is performed. Ground run-ups typically occur at night and generate high levels of noise for extended periods of time. In 1997, the Chicago Department of Aviation constructed a ground run-up enclosure (GRE) at O Hare to help reduce the noise impacts of ground run-ups on the communities surrounding the airport. This facility was the first of its kind in the United States. When it is not possible to use the GRE, run-ups are performed on one of the three identified alternative locations. The Airline Ground Run-up Report displays the total number of ground run ups from the current quarter by airline. The Aircraft Ground Run-up Report displays the total number of ground run ups from the current quarter by aircraft. Both reports compare the percent utilization of the GRE facility to the percent utilization of other locations for ground run-ups. It also compares the current quarter s GRE usage to the 12-month average and to the same quarter of the previous year. Aircraft Noise The Nighttime Aircraft Noise Report summarizes noise measurements from each of the 33 noise monitors located around O Hare. The data presented summarizes the Equivalent Sound Level (Leq). Leq is used to identify the average sound level over a given period of time (in this case 1 p.m. to 7 a.m.) and is the metric used for this analysis as it is the most appropriate noise measure for periods of time less than 24 hours. The data in this report displays the average Leq for the current quarter and its comparison to the previous four quarters. It also compares the current quarter s Leq to the 12-month average. Numbers displayed in red represent an increase of at least 1 db over the aircraft Leq from the same quarter of the previous year whereas numbers displayed in green represent a decrease of at least 1 db from the aircraft Leq from the same quarter of the previous year. Chicago Department of Aviation Page 2 3rd Quarter 216
Runway Use Report Period: 3 rd Quarter 216 Time of Day: 1: p.m. to 7: a.m. Runway Use (1 p.m. to 7 a.m.) Source: Airport Noise Management System (ANMS) Runway Utilization 4L 4R 9L 9R 1L 1C 1R 14R 22L 22R 27L 27R 28L 28C 28R 32L Average Daily Departures 3Q 216 1 21 14 4 2 2 5 33 25 2Q 216 29 16 2 11 3 33 24 12 Month Avg. 16 1 1 14 2 36 28 Average Daily Arrivals 3Q 216 5 8 5 7 29 4 1 11 39 3 25 1 2Q 216 11 5 16 36 1 2 46 3 24 6 12 Month Avg. 7 2 12 21 1 2 43 3 3 14 8% Departures (1 p.m. to 7 a.m.) 8% Arrivals (1 p.m. to 7 a.m.) 7% 7% 6% 6% 5% 5% 4% 4% 3% 3% 2% 2% 1% 1% % % Percentage Departure Utilization Percentage Arrival Utilization 3Q 216 1 # 3Q 216 8 5 2 2 2 17 3 26 27 11 5 1 7 4 4 2 17 16 # 4 Chicago Department of Aviation Page 3 3rd Quarter 216
Nighttime Hourly Operations Report Period: 3 rd Quarter 216 Time of Day: 1: p.m. to 7: a.m. Average Departures by Hour 7 6 Average Departures 5 4 3 49 48 33 34 2 18 14 9 9 1 7 5 3 3 4 3 2 2 1 1 1 p.m. 11 p.m. 12 a.m. 1 a.m. 2 a.m. 3 a.m. 4 a.m. 5 a.m. 6 a.m. Hour 3Q16 2Q16 12 Month Average* Operations by Hour (%) 3Q 216 1 p.m. 11 p.m 12 a.m. 1 a.m. 2 a.m. 3 a.m. 4 a.m. 5 a.m. 6 a.m. Total Departures 38.8% 14.4% 5.7% 2.7% 2.9% 1.3%.6% 7.1% 26.5% 1% Arrivals 15.8% 11.7% 5.9% 2.4%.9% 1.5% 7.9% 17.% 36.9% 1% Average Arrivals by Hour 7 6 55 59 Average Arrivals 5 4 3 2 1 23 21 17 18 9 8 4 3 1 1 2 2 12 13 25 25 1 p.m. 11 p.m. 12 a.m. 1 a.m. 2 a.m. 3 a.m. 4 a.m. 5 a.m. 6 a.m. Hour 3Q16 2Q16 12 Month Average* * 12 Month Average equals the average of 4Q 215, 1Q 216, 2Q 216 and 3Q 216. Chicago Department of Aviation Page 4 3rd Quarter 216
Nighttime Arrival Summary Period: 3 rd Quarter 216 Time of Day: 11: p.m. to 6: a.m. Runway 27L Arrivals 3 rd Quarter 216 3 rd Quarter 215 Arrivals Arrivals Airline AeroMexico 43 42 AeroUnion 1 1 Air Canada 17 -- Air Choice One 17 1 Alaska Airlines 7 25 America West Airlines 1 -- American Airlines 568 345 Atlas Air 4 -- Copa Airlines 11 19 Delta Air Lines 67 26 Delta Connection 6 4 Eastern Airlines 1 -- Envoy Air 573 172 FedEx 13 5 Frontier Airlines 81 61 JetBlue Airways 27 8 Kalitta Charters 1 -- LOT 1 -- Netjets 2 1 Netjets/Executive Jet Management 2 -- PSA Airlines 13 -- Republic Airlines 129 87 Sky Regional Airlines 6 3 Sky West Aviation 276 8 Solairus Aviation 1 -- Spirit Airlines 155 1 United Airlines 744 398 United Express/ASA 42 91 United Express/Gojet 17 31 United Express/Shuttle America 54 18 United Express/Trans States 69 3 UPS 15 6 Virgin America 3 14 Total 3,525 1,541 Chicago Department of Aviation Page 5 3rd Quarter 216
Nighttime Arrival Summary Period: 3 rd Quarter 216 Time of Day: 11: p.m. to 6: a.m. Runway 28C Arrivals 3 rd Quarter 216 3 rd Quarter 215 Arrivals Arrivals Airline AeroMexico 3 65 AeroUnion 3 1 Air Canada 3 -- Air China Cargo 8 24 Air Choice One 6 1 Air India 32 1 AirBridge Cargo Airlines 16 11 Alaska Airlines 18 21 American Airlines 318 537 Asiana Airlines 23 32 Atlas Air 19 4 British Airways 2 1 Cargolux Airlines 32 28 Cathay Pacific Airways 8 8 China Airlines 9 -- China Cargo Airlines 3 5 Copa Airlines 11 32 Delta Air Lines 25 2 Delta Private Jets 1 -- Emirates 11 5 Envoy Air 33 276 Eva Airways 3 -- FedEx 61 148 Finnair 1 -- Frontier Airlines 33 73 JetBlue Airways 4 4 Kalitta Air 1 -- Kalitta Charters 1 19 Korean Air Lines 19 -- Landmark Aviation 1 -- LOT 1 -- Lufthansa 1 -- Lufthansa Cargo 8 16 Miami Air International 1 -- National Air Cargo 1 -- Netjets 1 3 Netjets/Executive Jet Management 1 -- Nippon Cargo Airlines 15 4 Polar Air Cargo 8 2 PSA Airlines 29 -- Qantas Airways 6 1 Qatar Airways 12 18 Republic Airlines 114 167 Singapore Airlines Cargo 1 -- Sky Regional Airlines 1 1 Sky West Aviation 145 8 Spirit Airlines 81 122 United Airlines 392 493 United Express/ASA 188 17 United Express/Gojet 68 41 United Express/Shuttle America 49 31 United Express/Trans States 72 6 UPS 57 98 Virgin America 14 25 Volaris 1 1 Xtra Airways 2 -- Yangtze River Express Airlines 2 2 Total 2,33 2,543 Chicago Department of Aviation Page 6 3rd Quarter 216
Nighttime Preferential Flight Track Summary Period: 3 rd Quarter 216 Time of Day: 11: p.m. to 6: a.m. Runway 28R Departures Airline Aerologic 3.71 2.2 AeroMexico 29.36 42.22 Air China Cargo 9.48 11.3 Air France 1.43 -- -- AirBridge Cargo Airlines 9.64 11.42 Alaska Airlines 4.34 9.16 American Airlines 125.56 79.32 Asiana Airlines 3.4 15.17 Atlas Air 13.57 1.15 British Airways 1.33 1.45 Cargolux Airlines 9.49 16.32 Cathay Pacific Airways 9.55 19.3 China Airlines 1.28 -- -- China Cargo Airlines 4.55 3.37 Delta Air Lines 16.34 6.34 Emirates 5.54 6.39 Envoy Air 4.69 45.45 Eva Airways 4.74 -- -- FedEx 31.5 -- -- Finnair 2.28 11.42 Frontier Airlines 13.6 3.1 JetBlue Airways 2.13 5.12 Kalitta Air 1.4 1.18 Korean Air Lines 16.33 21.26 LOT 2.7 1 1.12 Lufthansa 11.57 14 1.2 Lufthansa Cargo 6.42 -- -- Nippon Cargo Airlines 8.36 16.37 Qantas Airways 3.57 1.1 Qatar Airways 9.46 2.36 Republic Airlines 18.54 11.67 Scandinavian Airlines 1.39 -- -- Sky Regional Airlines 4.67 3.94 Sky West Aviation 34.5 32.25 Spirit Airlines 42.39 44.3 Turkish Airlines 2.36 2 1.86 United Air Lines 131.53 43.39 United Express/ASA 21.59 27.29 United Express/Gojet 4.43 16.51 United Express/Shuttle America 14.28 2.17 United Express/Trans States 6.57 3.6 UPS 15.57 9.35 Yangtze River Express Airlines 2.31 2.41 Overall 71.47 553.4 Green represents a deviation of less than.5 nautical miles Orange represents a deviation between.5 and 1. nautical miles Red represents a deviation greater than 1. nautical mile 3 rd Quarter 216 Departures Average Deviation (nautical miles) 3 rd Quarter 215 Departures Average Deviation (nautical miles) Chicago Department of Aviation Page 7 3rd Quarter 216
Nighttime Preferential Flight Track Summary Period: 3 rd Quarter 216 Time of Day: 11: p.m. to 6: a.m. Runway 32L Departures Airline AeroMexico 42.11 63.15 AeroUnion 5.1 1.1 Air Canada 2.22 1 2.29 Air China Cargo 11.9 11.11 Air France 4.6 2.1 AirBridge Cargo Airlines 8.11 13.12 Alaska Airlines 11.12 1.13 American Airlines 192.31 16.21 Asiana Airlines 22.1 17.15 Atlas Air 29.15 6.3 British Airways 3.39 -- -- Cargolux Airlines 14.9 -- -- Cathay Pacific Airways 1.1 22.28 China Cargo Airlines 1. 8.8 Delta Air Lines 13.5 6.36 Emirates 11.6 9.8 Envoy Air 57.98 49.8 Eva Airways 1.5 1.64 FedEx 86.25 117.19 Finnair 1.1 2 2.21 Frontier Airlines 21.35 7.47 JetBlue Airways 4.12 2.12 Kalitta Air 6.8 1.27 Korean Air Lines 17.19 8.1 LOT 2.67 -- -- Lufthansa 13.52 15.7 Lufthansa Cargo 3.12 8.13 Netjets 3.16 4.6 Nippon Cargo Airlines 28.14 39.15 Polar Air Cargo 1.27 -- -- PSA Airlines 6 1.3 -- -- Qantas Airways 6.17 4.15 Qatar Airways 11.11 4.12 Republic Airlines 33.41 5.43 Royal Jordanian 1 2.19 -- -- Scandinavian Airlines 2.89 3.22 Sky Regional Airlines 8.97 3.87 Sky West Aviation 4.57 58.22 Spirit Airlines 58.31 66.38 Turkish Airlines 2.8 19.11 United Air Lines 274.47 249.31 United Express/ASA 36.67 52.31 United Express/Gojet 1.64 24.15 United Express/Shuttle America 22.27 61.31 United Express/Trans States 7.8 12.16 UPS 26.17 34.1 Virgin America 1.7 1.14 Yangtze River Express Airlines 3.11 3.19 Overall 1,167.34 1,225.33 Green represents a deviation of less than.5 nautical miles Orange represents a deviation between.5 and 1. nautical miles Red represents a deviation greater than 1. nautical mile 3 rd Quarter 216 Departures Average Deviation (nautical miles) 3 rd Quarter 215 Departures Average Deviation (nautical miles) Chicago Department of Aviation Page 8 3rd Quarter 216
Nighttime Flight Track Report Period: 3rd Quarter 216 Time of Day: 11: p.m. to 6: a.m. Existing Runways to be Decommissioned Preferential Flight Track Existing Runways Future Runways Runway Departures (in %) versus Deviation (in nautical miles) Deviation 4L 4R 9L 9R 1C 1L 1R 14R 22L 22R 27L 27R 28C 28L 28R 32L <.5 89% % 75% 67% 86% 53% 88% 71% 72%.5 < 1. 7% 75% 13% 18% 14% 33% 12% 19% 18% >1. 4% 25% 12% 15% % 14% % 1% 1% = not applicable Flight tracks shown until 3,' Mean Sea Level (MSL) Chicago Department of Aviation Page 9 3rd Quarter 216
Nighttime Noise Complaint Report Period: 3 rd Quarter 216 Time of Day: 1: p.m. to 7: a.m. Complaints by Community 1 Nature of Noise Complaints Community Total Complaints Number of Complainants Addison 119 5 Arlington Heights 6,99 19 Barrington 2 1 Bartlett 91 7 Batavia 1 1 Bensenville 56,217 81 Berkeley 3 3 Bloomingdale 2,88 92 Campton Hills 1 1 Carol Stream 1 1 Chicago 62,47 14,281 Ward 38 3,87 53 Ward 39 11,257 99 Ward 4 1,953 26 Ward 41 18,245 361 Ward 45 9,466 82 Ward Other 4,43 51 Ward Unknown 13,69 13,69 Des Plaines 24 39 Elgin 3,852 3,145 Elk Grove Village 14,814 8,171 Elmhurst 1,417 119 Elmwood Park 2 2 Evanston 94 3 Franklin Park 137 17 Geneva 28 5 Gilberts 4 1 Glen Ellyn 124 65 Glencoe 3 3 Glenview 1,88 48 Golf 1 1 Hampshire 1 1 Hanover Park 9 2 Harvard 8 28 Harwood Heights 365 9 Highland Park 1 1 Hillside 1 1 Hinsdale 8 3 Hoffman Estates 176 4 Inverness 3 2 Itasca 5,855 37 Kaneville 1 1 Kildeer 499 445 La Grange Park 9 9 Lake Zurich 1 1 Libertyville 1 1 Lincolnwood 1,477 122 Lisle 1 1 Lombard 53 1 Long Grove 1 1 Marengo 1 1 Maywood 1 1 Medinah 3,17 291 Melrose Park 91 6 Morton Grove 1 1 Mount Prospect 2,71 9 Naperville 2 1 Niles 2,457 16 Norridge 5,369 8 Northbrook 19 2 Northfield 2 1 Oak Lawn 2 1 Oak Park 4 2 Orland Park 2 1 Palatine 154 29 Park Ridge 14,739 574 Prospect Heights 2 2 River Forest 1,424 1,424 River Grove 23 3 Riverside 5 3 Rolling Meadows 34 5 Roselle 436 25 Rosemont 17 2 Schaumburg 5,699 2,959 Schiller Park 4,559 22 Skokie 152 6 Sleepy Hollow 154 1 South Barrington 2 2 St. Charles 1 1 Unincorporated Cook 888 888 Villa Park 68 9 Wayne 1,295 6 West Chicago 755 48 Westchester 9 1 Western Springs 26 5 Wheaton 1,19 7 Winfield 1 1 Winnettka 456 1 Wood Dale 26,369 624 Community Unknown 1,141 1,141 Aircraft Noise 51% Vibration 3% Not Reported % Low Flying 25% Frequency of Operations 21% 3Q 216 Total 23,634 35,28 2Q 216 Total 237,646 32,569 12 Month Average 2 24,26 35,986 1 Only includes calls made from the State of Illinois. 2 12 Month Average equals average of: 4Q 215, 1Q 216, 2Q 216 and 3Q 216. Chicago Department of Aviation Page 1 3rd Quarter 216
Airline Ground Run-Up Report Period: 3 rd Quarter 216 Time of Day: 24 Hours All Airlines 3 rd Quarter 216 2 nd Quarter 216 12 Month Avg. 1 Location Run-ups Percentage Run-ups Percentage Run-ups Percentage GRE 148 77% 163 77% 142 75% Other 45 23% 49 23% 48 25% Total 193 1% 212 1% 189 1% GRE 77 81% 77 88% 79 81% Other 18 19% 11 12% 18 19% Total 95 1% 88 1% 97 1% GRE 13 1% 21 1% 18 1% Other % % % Total 13 1% 21 1% 18 1% GRE 31 1% 39 1% 3 99% Other % % 1% Total 31 1% 39 1% 31 1% GRE 24 51% 15 31% 17 45% Other 23 49% 34 69% 2 55% Total 47 1% 49 1% 37 1% Other GRE 3 43% 11 73% 8 72% Other 4 57% 4 27% 3 28% Total 7 1% 15 1% 12 1% Ground Run-Up Locations 3Q 216 Other 23% GRE 77% 1 12 Month Average equals the average of: 4Q 215, 1Q 216, 2Q 216 and 3Q 216. Chicago Department of Aviation Page 11 3rd Quarter 216
Aircraft Ground Run-Up Report Period: 3 rd Quarter 216 Time of Day: 24 Hours 3 rd Quarter 216 2 nd Quarter 216 Aircraft Run-ups Total Run-ups in GRE Percentage Use of GRE Run-ups Total Run-ups in GRE Percentage Use of GRE A319 3 3 1% % A32 11 9 82% 8 6 75% B737 61 59 97% 47 44 94% B747 4 % 3 % B757 1 4 4% 2 3 15% B767 17 1 6% 17 3 18% B777 12 % 7 1 14% DC9Q % % E135/145 23 23 1% 26 26 1% MD8 26 26 1% 36 36 1% Regional Jet (unspecified type) 23 23 1% 44 44 1% Other 3 % 4 % TOTAL 193 148 77% 212 163 77% Chicago Department of Aviation Page 12 3rd Quarter 216
Chicago Department of Aviation Page 13 3rd Quarter 216
Nighttime Aircraft Noise Report Period: 3 rd Quarter 216 Time of Day: 1: p.m. to 7: a.m. Metric: Aircraft Leq RMT # Community Last 4 Quarters Monitored Noise Levels 1 4Q 215 1Q 216 2Q 216 3Q 216 3Q 215 12 Month Avg. 1 Arlington Heights 49.2 48.4 49.4 49.1 49.6 49.1 2 Melrose Park 5.1 44.3 47.8 49.8 48.1 48.5 3 Bensenville 54.2 54.1 54.1 54.8 53.9 54.3 4 Schiller Park 48.5 47.5 48.4 5. -- 48.7 5 Chicago 51.7 51.9 52.8 51.6 51.1 52. 7 Des Plaines 42.2 4.5 39.8 42.3 41.3 41.3 8 Des Plaines 44.8 43. 43.3 46.8 45.8 44.7 1 Rolling Meadows 44.2 43.9 47.9 49.8 44.7 47.2 11 Chicago 44.4 44.3 46.6 45.5 42.9 45.3 12 Elk Grove Village 52.1 53. 55.3 52.4 48.7 53.4 13 Elk Grove Village 61.1 59.4 6.8 61.5 61.4 6.8 14 Elk Grove Village 54.5 53.2 52.7 51.4 53.5 53.1 15 Franklin Park 41.5 39.7 4.9 45.3 38.2 42.4 16 Franklin Park 56. 53.9 52.3 54. 54.8 54.3 17 Harwood Heights 59.6 58.4 56.7 56.8 57. 58. 19 Stone Park 42.1 39.6 4.1 41.2 41.8 4.8 2 Mount Prospect 47.9 48.1 47.3 46.6 47.7 47.5 21 Mount Prospect 43.5 45.5 42.9 4.4 41.3 43.4 22 Norridge 6.8 59.4 59.5 59.1 58.4 59.8 23 Northlake 55.4 54.2 53.6 54.7 57.2 54.5 24 Park Ridge 43.2 41.5 43.5 46.8 39.5 44.2 25 Park Ridge 52.5 53.3 55.3 53.9 5.6 53.9 26 Park Ridge 46.5 44.2 47.3 46.2 42.6 46.2 27 Rosemont 59.7 59.9 62.4 61.1 56.1 6.9 28 Schiller Park 66.6 64.1 66.4 66.7 64.9 66.1 29 Wood Dale 58.4 57.8 6.5 59.1 58.4 59.1 3 Wood Dale 44. 43.6 43.4 48.8 44.4 45.6 32 Wood Dale 58.6 58.6 58.6 57.7 58.6 58.4 33 Park Ridge 51.1 47.6 5.7 5.3 5.6 5.1 34 Elk Grove Village 5.7 5.3 55.8 5.8 49.6 52.6 35 Unincorporated Cook 5.1 47.6 46.9 47.4 48.5 48.2 37 Mount Prospect 38.1 39.4 38.3 39.7 37.4 38.9 42 Chicago 46.9 44.9 47.8 47.2 45.5 46.8 1 Leq (Equivalent Sound Level): The average sound energy level during a stated period of time. Red represents an increase of 1 db or more from same quarter of the previous year (15 monitors). Green represents a decrease of 1 db or more from same quarter of the previous year (4 monitors). Chicago Department of Aviation Page 14 3rd Quarter 216
Chicago Department of Aviation O Hare Noise Hotline: 1-8-435-9569 www.flychicago.com/ordnoise