Near-surface hazardous emissions from global civil aviation LTO cycles: Estimation and mitigation strategies

The civil aviation sector continues to experience rapid growth, contributing significantly to fossil fuel consumption and hazardous atmospheric pollutant emissions. Emissions from landing-takeoff (LTO) cycles accumulate near ground level around airports, exacerbating local air quality deterioration and posing potential health risks to nearby populations. This study estimates fuel consumption and pollutant emissions during LTO cycles of global civil aviation, analyzes population exposure at major urban airports, and evaluates the effectiveness of mitigation strategies in mitigating exposure-related risks. For the first time, we develop country-specific emission indices (EIs) and fuel flow (FF) parameters for 180 countries, revealing that the EIs for the same aircraft type can differ by up to several tens of times across countries. We further demonstrate that the commonly applied universal constant EI may introduce substantial representational bias by neglecting national differences in fleet-engine configurations, while a country-specific EI enhances the granularity of national fleet structure characterization. We introduce an Exposure Density Index to provide a population-normalized proxy for assessing urban exposure burden and environmental inequality associated with aviation activities. Furthermore, multi-scenario mitigation analysis, including management optimization, fleet configuration upgrades, and sustainable aviation fuel substitution, reveals substantial mitigation potential and spatial heterogeneity in risk reduction benefits. Our findings provide a scientific basis for developing policies to mitigate aviation-related pollution, reduce urban exposure burdens, and support greener aviation development.