Haze, a relatively complex and frequently observed weather element, can have a significant impact on the efficiency of air traffic operations at major airports throughout the National Airspace System (NAS). Visibility through a haze layer – especially at shallow angles, often reduces a normal visibility day (7-10 statute miles [SM]) to less than 3SM. Aircrafts penetrating through this layer during decent or final approach have difficulty seeing the runway or the aircraft immediately ahead resulting in the airport switching to an Instrument Landing System (ILS) approach or increasing the distance between aircraft during final decent, effectively reducing airport capacity. The operational impact of haze increases significantly when an airport is experiencing high demand which may result in increased delays and costs for airlines.

This study investigated haze conditions, and resultant air traffic impacts, at several major airports, including Atlanta (ATL), Newark (EWR), Chicago O'Hare (ORD), Denver (DEN), and Los Angeles (LAX). Results from this study show that haze conditions contribute to reduced airport arrival rates and often require traffic management initiatives to mitigate the effects of this weather constraint. Identified haze impacts include increased airborne holding, excess fuel burn, decreased airport arrival capacity, over-delivery, and delay. Additionally, this study investigated the frequency and accuracy of haze predictions from the Terminal Aerodrome Forecast (TAF) product, as well as the correlation of these forecasts to the use of haze-related traffic management programs. Results from this study will also demonstrate the difficulties associated with forecasting haze due to limited upper air observations and lack of reliability and correlation with the surface observations. Additional implications from weather forecast requirements and weather-translation perspectives are explored in this study.