As part of the CAEP/12 (2022) update to the ICAO Global Environmental Trends, a range of scenarios were developed for the assessment of future LAQ NOx and PM emission trends.

The LAQ portion of the trends assessment evaluated potential contributions of operational and technology improvements to reducing projected emissions of NOx and potential contributions of operational improvements to reducing projected emissions of the particulate matter (PM). The results are based on the CAEP/12 2018 to 2050 post COVID traffic and fleet forecast, representing NOx, non-volatile PM and Total PM emissions below 3 000 feet. NOx technology improvement scenarios leverage the latest Independent Experts (IE) work.

NOx emissions below 3 000 feet from international aviation are shown in Figure 8. In 2050, depending upon the scenario, technology improvements could provide up to 0.21 Mt of reductions in NOx emissions for international aviation. Operational improvements are smaller than those that could be realized by technology, namely additional reductions of up to 0.03 Mt in 2050 for international aviation.

Non-volatile PM emissions below 3 000 feet from international aviation are shown in Figure 9. In 2050, operational improvements could provide additional reductions of up to 50 tonnes in
nvPM emissions for international aviation.
Total (volatile and non-volatile) PM emissions below 3 000 feet from international aviation are shown in Figure 10. In 2050, operational improvements could provide additional reductions of up to 150 tonnes in PM emissions for international aviation.