Every year, the International Day of Clean Air for Blue Skies is commemorated globally on the 7th of September. Like international aviation, air pollution knows no borders: everyone is affected by it, and everyone shares the responsibility to ensure that the air we breathe is clean. The UN Sustainable Goal (SDG) 3, Good Health and Well-being, also calls for a substantial reduction in deaths and illnesses from air pollution. As international aviation continues to connect people and economies, ICAO is committed to ensuring that this connectivity goes hand-in-hand with protecting the atmosphere. Through its environmental standards, collaborative partnerships, and targeted initiatives, ICAO is taking concrete action to reduce international aviation-related emissions, improve air quality, and build climate resilience.
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Strengthening standards: Annex 16 and CAEP updates
Strengthening standards: Annex 16 and CAEP updatesOne of the cornerstones of ICAO’s work on air quality is our environmental standards, which provide a global framework for reducing the impact of aviation emissions on health and the environment. In line with ICAO Assembly Resolution A41-20, ICAO, with Member States, shares a responsibility to limit or reduce the impact of aviation emissions on local air quality (LAQ). The existing LAQ considerations focus on aircraft engine emissions released below 3,000 feet (914 meters) and emissions from airport sources, such as airport traffic, ground service equipment, and de-icing operations, among others.
To address aircraft engine emissions, ICAO established measures through Annex 16, Volume II, which contains Standards and Recommended Practices (SARPs) for environmental certification of aircraft engines. These SARPs set limits on the amounts of gaseous and non-volatile particulate matter emissions allowed in the exhaust of civil aircraft engines, helping protect human health and welfare from the adverse effects of air pollutants.
During their 13th work cycle in 2022-2025, ICAO’s Committee of Aviation Environmental Protection (CAEP) under the Emissions Technical Working Group (WG3) successfully developed and recommended several Annex 16, Volume II amendments for consideration by the ICAO Council. These amendments are summarized in Chapter 11 of the 2025 Environment Report. For the upcoming triennium, CAEP will continue addressing LAQ issues by, for example, pursuing more stringent NOx emissions standard and developing approaches to establish a ‘gold standard’ for LAQ dispersion modelling.
These efforts to strengthen global standards form the foundation of ICAO’s broader approach to air quality, which also extends to airports and ground operations.
On the ground and in the air: mitigation and adaptation at airports
Efforts to improve air quality also extend to airport operations. Airports are vital hubs of the aviation network, and they are also key players in advancing cleaner air and climate resilience. Around the world, airports are adopting innovative measures: from electrifying ground support equipment and installing renewable energy systems, to implementing green infrastructure that can adapt to climate impacts.
We support these initiatives by developing guidance and fostering knowledge exchange, enabling airports to scale up measures that reduce emissions while strengthening resilience to environmental challenges. These actions, combined with our global standards and programmes, contribute to a more sustainable future for the aviation sector.
The ICAO Doc 9889 – Airport Air Quality Manual is regularly updated to provide ICAO Member States with practical guidance on applying best practices for managing airport-related air quality. CAEP/13 recommended further improvements to the manual, including a new method of estimating emissions of volatile particulate matter, updated guidance on the effects of sustainable aviation fuels (SAF), and clearer instructions on how to address missing data points.
These technical measures are a part of a broader approach to tackling aviation-related air pollution, which also involves responding to environmental threats beyond airport boundaries, such as the growing risks posed by wildfires.
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Addressing the smoke in the skies: forest fires and air pollution
Addressing the smoke in the skies: forest fires and air pollutionAs stated by the Food and Agriculture Organization (FAO), wildfires are becoming more frequent and intense due to rising global temperatures, prolonged droughts, and shifting weather patterns, all driven by climate change. According to Global Forest Watch, between 2001 and 2024, wildfires were responsible for the loss of 152 million hectares of tree cover, accounting for 29% of total global tree cover loss. The burning of forests, grasslands, and agricultural fields release large quantities of polluting gases and solid particles, including particulate matter such as black carbon, and trace gases such as carbon monoxide and nitrogen oxides. These pollutants can persist for hours or even days, often at significant intensities.
The human health impacts are severe, ranging from respiratory and cardiovascular illness to increased mortality. These fires also disrupt aviation operations, impair visibility, and damage ecosystems. For instance, the wave of wildfires in the first half of 2025 has already forced airport closures and flight cancellations from Canada to France, Italy, and Türkiye. To address these threats, effective wildfire management supported by aerial response capacities is crucial.
The ICAO Flying Forest Fire Fighting (I4F) Dialogue, launched in 2021, facilitates the exchange of information on existing activities, technologies and arrangements, while promoting cooperation among States and stakeholders through knowledge exchange. The 2021 I4F Dialogue identified the need to establish an informal multi-stakeholder working group involving ICAO, the Global Fire Monitoring Center (GFMC), the International Search and Rescue Advisory Group (INSARAG) and the UNEP/United Nations Office for the Coordination of Humanitarian Affairs (UNEP/OCHA) Joint Environment Unit (JEU).
It also emphasized the importance of identifying focal points across ICAO Member States to raise awareness and gain support for forest fire fighting efforts, which was also addressed during ICAO’s Aviation Climate Week. ICAO continues to work closely with these stakeholders to advance wildfire fighting efforts, including preparations for the upcoming 30th United Nations Climate Change Conference of the Parties (COP30), which will take place in Belém, Brazil, from 10 to 21 November 2025.
Clean air as a common destination
The path to cleaner air and deep blue skies requires collaboration, innovation, and a shared commitment to sustainability. ICAO’s work, through setting global standards for aircraft and airport operations, and initiatives like I4F, shows how the aviation sector can be part of the solution. On this International Day of Clean Air for Blue Skies, ICAO reaffirms its dedication to ensuring that aviation continues to connect the world while contributing towards cleaner air for all.
