Modeling aviation’s air quality impacts over time in the context of the changing atmospheric composition

Aviation’s growth has historically outpaced technological and operational improvements to mitigate emissions. Despite the short-term slowdown due to COVID-19, the sector’s growth is forecast to resume in the coming years. Being a unique sector in terms of the altitude that the majority of the emissions are deposited in, aviation contributes to air pollution near and far from airports, in the form of PM_2.5, ozone, and NO₂, through a series of chemical and physical pathways. Aviation’s growth is heterogeneous globally, with emissions in some regions (e.g., Asia) growing faster than elsewhere (e.g., Europe and North America).

Using recent aviation emissions inventories and future forecasts, and the GEOS-Chem global atmospheric chemistry-transport model, we quantify aviation’s global air quality and associated human health impacts in recent years and under different future atmospheric pathways. Both emissions during landing and take-off operations and emissions during cruise are assessed in different regions globally. We isolate the air quality changes attributable purely to the growth of aviation emissions, and those associated with the evolving (background) atmospheric composition which affects the nonlinear pathways between aviation emission and air pollution formation. Given the long timelines associated with the aviation sector, our results highlight the need for the integrated assessment of present-day and future aviation impacts together with those of other evolving sources.