Fly Quiet Program Chicago O Hare International Airport

4 th Quarter 215 Report Fly Quiet Program Chicago O Hare International Airport Visit the O Hare Noise Webpage on the Internet at www.flychicago.com/ordnoise

4 th Quarter 215 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 eight 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 4Q 215 include: Departures Arrivals Most used nighttime departure runway: 28R 31% Most used nighttime arrival runway: 28C 27% 1L night departures increased by 7pp from 3Q 215 28R night arrivals increased by 11pp from 3Q 215 22L night departures decreased by 5pp from 3Q 215 28C night arrivals decreased by 9pp from 3Q 215 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 Chicago Department of Aviation Page 1 4th Quarter 215

flight 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 (28R and 32L); 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 4th Quarter 215

Runway Use Report Period: 4 th Quarter 215 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 14L 14R 22L 22R 27L 27R 28L 28C 28R 32L 32R Average Daily Departures 4Q 215 9 1 1 18 3 33 32 3Q 215 1 6 4 2 27 6 37 34 3 12 Month Avg. 1 11 8 2 2 5 41 21 2 Average Daily Arrivals 4Q 215 6 1 1 19 1 3 1 31 6 38 25 3Q 215 1 4 4 6 19 1 45 9 56 11 12 Month Avg. 1 4 3 9 18 3 46 7 37 13 Departures (1 p.m. to 7 a.m.) Arrivals (1 p.m. to 7 a.m.) 8% 8% 7% 7% 6% 6% 5% 5% 4% 4% 3% 3% 2% 2% 1% 1% % % Percentage Departure Utilization Percentage Arrival Utilization 4Q 215 4Q 215 4 5 3 2 9 1 22 31 1 7 18 2 1 13 27 1 17 Purple denotes Fly Quiet preferential departure and arrival runways. Runway 1R-28L was commissioned on October 15, 215. Chicago Department of Aviation Page 3 4th Quarter 215

Nighttime Hourly Operations Report Period: 4 th Quarter 215 Time of Day: 1: p.m. to 7: a.m. Average Departures by Hour 7 6 Average Departures 5 4 3 43 44 31 41 2 15 11 8 6 1 6 6 4 3 3 2 1 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 4Q15 3Q15 12 Month Average* Operations by Hour (%) 4Q 215 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 39.8% 1.% 5.5% 3.5% 2.5% 1.2% 1.% 7.8% 28.7% 1% Arrivals 14.7% 11.9% 4.5% 1.9% 1.1% 1.7% 8.5% 15.6% 4.1% 1% Average Arrivals by Hour 7 6 57 54 Average Arrivals 5 4 3 2 1 21 22 17 17 6 7 3 3 1 1 2 2 12 9 22 28 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 4Q15 3Q15 12 Month Average* * 12 Month Average equals the average of 1Q 215, 2Q 215, 3Q 215 and 4Q 215. Chicago Department of Aviation Page 4 4th Quarter 215

Nighttime Arrival Summary Period: 4 th Quarter 215 Time of Day: 11: p.m. to 6: a.m. Runway 28C Arrivals 4 th Quarter 215 4 th Quarter 214 Arrivals Arrivals Airline AeroMexico 27 15 AeroUnion 2 1 Air China Cargo 6 4 Air India 4 14 AirBridge Cargo Airlines 7 4 Alaska Airlines 14 8 American Airlines 268 69 Asiana Airlines 8 5 Atlas Air 2 29 Cargolux Airlines 17 7 Cathay Pacific Airways 3 3 China Airlines 5 2 China Cargo Airlines 4 1 China Southern Airlines 1 -- Copa Airlines 9 3 Delta Air Lines 6 1 Delta Connection 1 -- DHL/Airborne Express 19 -- Eastern Airlines 1 -- Emirates 5 1 Envoy Air 259 47 FedEx 74 1 Frontier Airlines 26 4 JetBlue Airways 1 4 Kalitta Air 1 2 Korean Air Lines 4 7 Lufthansa Cargo 5 2 Martinair 4 -- National Air Cargo 2 2 Netjets 2 1 Nippon Cargo Airlines 2 1 Polar Air Cargo 3 3 Qantas Airways 3 2 Qatar Airways 9 3 Republic Airlines 45 -- Scandinavian Airlines 1 -- Sky Lease Cargo 1 -- Sky West Aviation 46 29 Spirit Airlines 61 25 Swift Air 3 3 TNT Airways 6 -- United Airlines 261 121 United Express/ASA 3 34 United Express/Gojet 14 15 United Express/Shuttle America 13 25 United Express/Trans States 1 19 UPS 54 6 Virgin America 13 4 XOJet 1 -- Yangtze River Express Airlines 1 1 Total 1,364 693 Chicago Department of Aviation Page 5 4th Quarter 215

Nighttime Arrival Summary Period: 4 th Quarter 215 Time of Day: 11: p.m. to 6: a.m. Runway 27L Arrivals 4 th Quarter 215 4 th Quarter 214 Arrivals Arrivals Airline AeroMexico 33 148 AeroUnion 1 -- Air Choice One 1 3 Alaska Airlines 21 63 American Airlines 186 423 American Eagle/Air Wisconsin 1 -- Asiana Airlines 1 -- Atlas Air 1 27 Aviacsa 1 -- Copa Airlines 12 39 Delta Air Lines 8 8 Delta Connection 1 5 DHL/Airborne Express 5 -- Envoy Air 139 286 Frontier Airlines 33 63 JetBlue Airways 4 32 Korean Air Lines 1 -- Lufthansa Cargo 1 1 Netjets 1 4 Qatar Airways 1 2 Republic Airlines 16 63 Sky West Aviation 36 154 Spirit Airlines 75 23 Swift Air 4 16 TNT Airways 1 -- United Airlines 267 817 United Express/ASA 33 185 United Express/Gojet 17 8 United Express/Shuttle America 1 54 United Express/Trans States 8 89 UPS 2 21 Virgin America 17 54 Worldwide Jet 1 -- Total 939 2,867 Chicago Department of Aviation Page 6 4th Quarter 215

Nighttime Preferential Flight Track Summary Period: 4 th Quarter 215 Time of Day: 11: p.m. to 6: a.m. Runway 28R Departures Airline Aerologic 8.38 3.19 AeroMexico 56.17 133.19 AeroUnion 3.13 8.18 Air China Cargo 21.34 39.37 Air Choice One 1 1.59 4 1.11 Air France 1.3 7.35 AirBridge Cargo Airlines 18.46 33.55 Alaska Airlines 1.48 1.34 American Airlines 117.27 17.42 Asiana Airlines 41.35 49.17 Atlas Air 2.69 33.23 Cargolux Airlines 34.26 28.36 Cathay Pacific Airways 14.21 55.49 China Cargo Airlines 14.29 1.36 Delta Air Lines 8.27 17.21 DHL/Airborne Express 5.42 -- -- Emirates 2.38 9.45 Envoy Air 16.33 173.36 Eva Airways 3.17 3.33 FedEx 3.29 14.31 Frontier Airlines 3.19 3.3 JetBlue Airways 3.12 13.26 Kalitta Air 3.47 4.21 Korean Air Lines 42.2 7.23 LOT 3.31 3.68 Lufthansa 1.9 1.3 Lufthansa Cargo 17.35 8.41 National Air Cargo Group 2.12 1.6 Nippon Cargo Airlines 32.32 5.41 Polar Air Cargo 5.12 -- -- Qantas Airways 9.57 2.22 Qatar Airways 12.39 4.37 Republic Airlines 1.5 125.33 Royal Jordanian Airlines 3.34 1.86 Scandinavian Airlines 8.31 1.52 Singapore Airlines Cargo 1.1 -- -- Sky West Aviation 4 1.1 59.38 Spirit Airlines 42.34 4.25 Swift Air 3.22 9.16 TNT Airways 11.25 -- -- Turkish Airlines 4.34 4.39 United Air Lines 83.38 82.34 United Express/ASA 7.3 71.33 United Express/Gojet 11.27 -- -- United Express/Shuttle America 5.13 67.2 United Express/Trans States 2.36 32.24 UPS 3.21 65.15 Yangtze River Express Airlines 2.48 8.17 Overall 762.33 1,575.34 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 4 th Quarter 215 Departures Average Deviation (nautical miles) 4 th Quarter 214 Departures Average Deviation (nautical miles) Chicago Department of Aviation Page 7 4th Quarter 215

Nighttime Preferential Flight Track Summary Period: 4 th Quarter 215 Time of Day: 11: p.m. to 6: a.m. Runway 32L Departures Orange represents a deviation between.5 and 1. nautical miles Red represents a deviation greater than 1. nautical mile 4 th Quarter 215 4 th Quarter 214 Average Average Departures Deviation Departures Deviation Airline (nautical miles) (nautical miles) Aer Lingus 3.4 -- -- Aerologic 2.44 1.22 AeroMexico 42.16 5.22 AeroUnion 1.16 -- -- Air Canada 1.54 -- -- Air China Cargo 3.12 -- -- Air France 3.11 1.7 Air Nunavut 1.9 -- -- AirBridge Cargo Airlines 1.28 -- -- Alaska Airlines 2.59 -- -- America West Airlines 1.15 2.11 American Airlines 143.27 3.1 Asiana Airlines 15.14 -- -- Atlas Air 9.19 1.14 British Airways 1.3 -- -- Cargolux Airlines 13.3 4.14 Cathay Pacific Airways 6.36 1.1 China Cargo Airlines 12.25 -- -- Delta Air Lines 9.4 -- -- DHL/Airborne Express 21.21 -- -- Eastern Airlines 1.23 -- -- Emirates 1.16 -- -- Envoy Air 79.3 1.11 FedEx 17.2 4.6 Frontier Airlines 13.17 -- -- JetBlue Airways 2 1.15 -- -- Kalitta Air 4.29 2.11 Korean Air Lines 15.14 -- -- Landmark Aviation 1.4 -- -- LOT 1.32 1.1 Lufthansa 2.7 -- -- Lufthansa Cargo 1.13 1.1 National Air Cargo 2.27 -- -- Netjets 3.14 -- -- Nippon Cargo Airlines 27.15 -- -- Qantas Airways 1.9 -- -- Qatar Airways Company 4.22 1. Republic Airlines 19.41 -- -- Royal Jordanian 1.9 -- -- Scandinavian Airlines 4.37 -- -- Singapore Airlines Cargo 1.27 -- -- Sky Lease Cargo 1.21 -- -- Sky Regional Airlines 1.69 -- -- Sky West Aviation 47.21 -- -- Spirit Airlines 33.16 2.14 Swift Air 2.1 -- -- TNT Airways 3.2 -- -- Turkish Airlines 3.49 -- -- Ultimate Air Shuttle 2.13 -- -- United Airlines 191.27 6.17 United Express/ASA 43.13 5.5 United Express/Gojet 5.27 2.12 United Express/Shuttle America 28.23 5.12 United Express/Trans States 8.15 -- -- UPS 43.16 3.4 WestJet Airlines 1.22 -- -- Yangtze River Express Airlines 1.1 -- -- Overall 1,62.24 12.73 Green represents a deviation of less than.5 nautical miles Chicago Department of Aviation Page 8 4th Quarter 215

Nighttime Flight Track Report Period: 4th Quarter 215 Time of Day: 11: p.m. to 6: a.m. Preferential Flight Track Existing Runways to be Decommissioned 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 <.5 91% 84% 71% 48% 81% 79%.5 < 1. 4% 9% % 44% 6% 19% >1. 5% 7% 29% 8% 13% 2% = not applicable Flight tracks shown until 3,' Mean Sea Level (MSL) Chicago Department of Aviation Page 9 4th Quarter 215

Nighttime Noise Complaint Report Period: 4 th Quarter 215 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 4 9 Arlington Heights 2,43 18 Barrington Hills 2 1 Bartlett 1 3 Bensenville 73,921 12 Berkeley 1 1 Bloomingdale 1,329 35 Buffalo Grove 1 1 Carol Stream 4 3 Chicago 85,432 16,344 Ward 38 7,15 114 Ward 39 15,77 224 Ward 4 4,96 79 Ward 41 17,428 369 Ward 45 7,391 496 Ward Other 15,841 188 Ward Unknown 18,418 14,874 Chicago Ridge 9 2 Des Plaines 52 11 Elgin 213 9 Elk Grove Village 1,969 6,126 Elmhurst 36 15 Evanston 1 1 Forest Park 1 1 Frankfort 14 2 Franklin Park 56 2 Glen Ellyn 973 4 Glendale Heights 1 1 Glenview 18 8 Hanover Park 5 2 Harvard 49 2 Harwood Heights 1,194 85 Hillside 17 9 Inverness 2 2 Itasca 11,843 96 Kenilworth 4 1 Lake Zurich 2 2 Lincolnwood 1,198 136 Medinah 53 8 Mount Prospect 1,29 15 Niles 1,253 13 Norridge 3,319 223 Northbrook 25 5 Northlake 13 1 Oak Park 1 1 Palatine 2 1 Park Ridge 7,172 162 River Forest 982 982 River Grove 3 1 Riverside 14 3 Rolling Meadows 1 1 Roscoe 7 1 Roselle 547 11 Rosemont 3 3 Saint Charles 7 6 Schaumburg 3,828 3,25 Schiller Park 4,49 53 Skokie 5 3 St. Charles 4 2 Wayne 1,594 4 Wellington 67 1 West Chicago 471 7 Wheaton 27 4 Wood Dale 11,41 4,758 Community Unknown 17,673 3,738 Aircraft Noise 51% Vibration 6% Not Reported % Low Flying 24% Frequency of Operations 19% 4Q 215 Total 244,493 36,264 3Q 215 Total 27,483 33,842 12 Month Average 2 219,815 26,725 1 Only includes calls made from the State of Illinois. 2 12 Month Average equals average of: 1Q 215, 2Q 215, 3Q 215 and 4Q 215. Chicago Department of Aviation Page 1 4th Quarter 215

Airline Ground Run-Up Report Period: 4 th Quarter 215 Time of Day: 24 Hours All Airlines 4 th Quarter 215 3 rd Quarter 215 12 Month Avg. 1 Location Run-ups Percentage Run-ups Percentage Run-ups Percentage GRE 132 8% 14 78% 146 72% Other 33 2% 39 22% 56 28% Total 165 1% 179 1% 22 1% GRE 8 8% 78 74% 62 71% Other 2 2% 27 26% 25 29% Total 1 1% 15 1% 87 1% GRE 17 1% 17 1% 18 1% Other % % % Total 17 1% 17 1% 18 1% GRE 2 1% 19 1% 3 1% Other % % % Total 2 1% 19 1% 3 1% GRE 12 5% 16 57% 13 33% Other 12 5% 12 43% 28 67% Total 24 1% 28 1% 41 1% Other GRE 3 75% 1 1% 1 89% Other 1 25% % 1 11% Total 4 1% 1 1% 11 1% Ground Run-Up Locations 4Q 215 Other 2% GRE 8% 1 12 Month Average equals the average of: 1Q 215, 2Q 215, 3Q 215 and 4Q 215. Chicago Department of Aviation Page 11 4th Quarter 215

Aircraft Ground Run-Up Report Period: 4 th Quarter 215 Time of Day: 24 Hours 4 th Quarter 215 3 rd Quarter 215 Aircraft Run-ups Total Run-ups in GRE Percentage Use of GRE Run-ups Total Run-ups in GRE Percentage Use of GRE A319 1 1 1% 2 2 1% A32 4 2 5% 9 8 89% B737 59 53 9% 42 4 95% B747 5 % 3 % B757 1 % 3 1 33% B767 14 1 7% 25 2 8% B777 6 1 17% 7 % DC9Q % % E135/145 18 18 1% 15 15 1% MD8 32 32 1% 42 42 1% Regional Jet (unspecified type) 23 23 1% 3 3 1% Other 2 1 5% 1 % TOTAL 165 132 8% 179 14 78% Chicago Department of Aviation Page 12 4th Quarter 215

Chicago Department of Aviation Page 13 4th Quarter 215

Nighttime Aircraft Noise Report Period: 4 th Quarter 215 Time of Day: 1: p.m. to 7: a.m. Metric: Aircraft Leq RMT # Community Last 4 Quarters Monitored Noise Levels 1 1Q 215 2Q 215 3Q 215 4Q 215 4Q 214 12 Month Avg. 1 Arlington Heights 45.9 47.4 49.6 49.2 44.6 48.3 2 Melrose Park 42.2 46.9 48.1 5.1 4. 47.6 3 Bensenville 54.6 55.8 53.9 54.2 56.1 54.7 4 Schiller Park 42.2 47.2 -- 48.5 42. 43.4 5 Chicago 52.1 53.3 51.1 51.7 52.9 52.1 7 Des Plaines 41.4 42.5 41.3 42.2 43.1 41.9 8 Des Plaines 44.9 49.6 45.8 44.8 42.8 46.8 1 Rolling Meadows 44.3 44.8 44.7 44.2 42.1 44.5 11 Chicago 43.1 45.9 42.9 44.4 42.3 44.3 12 Elk Grove Village 51.4 53. 48.7 52.1 51.4 51.6 13 Elk Grove Village 56.6 58. 61.4 61.1 53.2 59.7 14 Elk Grove Village 49. 52.2 53.5 54.5 47.3 52.7 15 Franklin Park 4.1 42.3 38.2 41.5 39.5 4.8 16 Franklin Park 55.3 56.5 54.8 56. 56.1 55.7 17 Harwood Heights 55.3 55.8 57. 59.6 56.7 57.2 19 Stone Park 4.8 42.4 41.8 42.1 4.7 41.8 2 Mount Prospect 44.7 46.2 47.7 47.9 44.5 46.8 21 Mount Prospect 38.1 39.2 41.3 43.5 38.3 41. 22 Norridge -- -- 58.4 6.8 57.7 56.8 23 Northlake 54.6 56. 57.2 55.4 55.5 55.9 24 Park Ridge 39.5 43.9 39.5 43.2 39.6 42. 25 Park Ridge 51.3 54.4 5.6 52.5 52.1 52.4 26 Park Ridge 42.5 46.8 42.6 46.5 43.5 45.1 27 Rosemont 57.1 6.3 56.1 59.7 58.2 58.6 28 Schiller Park 66.8 66.4 64.9 66.6 67.8 66.2 29 Wood Dale 56.9 6.1 58.4 58.4 57. 58.6 3 Wood Dale 42.4 44.1 44.4 44. 45.2 43.8 32 Wood Dale 58.8 59.4 58.6 58.6 6.9 58.9 33 Park Ridge 48.1 51.8 5.6 51.1 49.7 5.6 34 Elk Grove Village 49.2 51.5 49.6 5.7 51.4 5.4 35 Unincorporated Cook 47.4 48.9 48.5 5.1 48.8 48.8 37 Mount Prospect 35.6 37.4 37.4 38.1 35.6 37.2 42 Chicago -- -- 45.5 46.9 -- 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 (21 monitors). Green represents a decrease of 1 db or more from same quarter of the previous year (5 monitors). Chicago Department of Aviation Page 14 4th Quarter 215

Chicago Department of Aviation O Hare Noise Hotline: 1-8-435-9569 www.flychicago.com/ordnoise