Statement by Chief Scientists for the 2022 International Day of Clean Air for blue skies

The Chief Scientists of the World Health Organization (WHO), the International Union for Conservation of Nature (IUCN), the World Meteorological Organization (WMO) and the UN Environment Programme (UNEP) have come together to highlight the theme of the 2022 International Day of Clean Air for blue skies, "The Air We Share," stressing collaboration and connection.

Air pollution is at the heart of global public health, economy, agriculture, biodiversity, environment and climate crisis that both affects and needs the urgent attention of all sectors of society. The evidence is overwhelming: exposure to air pollution adversely affects the health of all, but particularly the most vulnerable, the young and old, those with underlying health issues and above all children from prenatal, to neonates and infants during important developmental stages.

Today, less than one percent of humanity breathes air which meets the WHO’s strictest air quality guidelines. According to WHO’s estimates, there are 7 million premature deaths a year, including roughly 600,000 children under the age of 15 years as a consequence of air pollution – without accounting for the many additional millions who suffer from air pollution-related chronic illnesses.

The Chief Scientists of the World Health Organization (WHO), the International Union for Conservation of Nature (IUCN), the World Meteorological Organization (WMO) and the UN Environment Programme (UNEP) have come together to highlight this critical issue that affects all. This is why the theme of the 2022 International Day of Clean Air for blue skies is the Air We Share, stressing collaboration and connection.

Air pollution also affects other systems such as ecosystems. Sulphur and nitrogen deposition can, result in both acidification and eutrophication (over-enriched with nutrients) of water systems. Tropospheric ozone can have negative impacts on ecosystems leading to loss of biodiversity and negatively impacting plant growth, vitality, photosynthesis, water balance, flowering processes as well as the ability of vegetation to sequester carbon. The IUCN Red List of Threatened Species incorporates classification of threats to biodiversity including a sub-class for air-borne pollutants. For terrestrial vertebrates alone, there are 7,427 threatened species, of which 1,181 are classified as threatened by pollution and 64 specifically classified as threatened by air-borne pollutants.

Exposure to ozone can also lead to reduced yields of major crops between 1-15 percent and affect their nutritional value. Recent studies showed that the increase of carbon in the atmosphere is impacting negatively the nutritional quality of our food. Studies have estimated that annual economic losses owing to the impact of ozone on 23 crops amounted to US$26 billion in 2006. Air pollution can even impact water systems when harmful concentrations of pollutants accumulate or by reducing the ability of vegetation to filter water systems.

Air pollution has high economic costs - for example, through lost work or school days due to chronic diseases such as asthma, increased health care costs, reduced crop yields, and reduced competitiveness of globally connected cities. In 2021, a World Bank study found that the economic cost of the health impacts of air pollution alone amounted to US$8.1 trillion, equivalent to 6.1 percent of global Gross Domestic Product (GDP) in 2019.

The greatest impacts of air pollution are often in areas near the source of emissions, but many air pollutants can travel or form in the atmosphere hundreds to thousands of kilometres from a source of emission, causing regional and continental impacts. For example, soil mineral dust and sand, which makes up approximately 40% of total aerosols in the lower atmosphere, can remain in the atmosphere for as much as a week allowing it to be transported over continents and has a global impact on health, agriculture, transport, economy, and climate.

Finally, air pollution is strongly linked to climate change, with many greenhouse gases and air pollutants being emitted by the same sources. This means that the adoption of coherent policies and measures aimed at reducing emission of climate pollutants could also have beneficial impacts on air quality. Conversely, they can also aggravate each other in multiple ways. Rising temperatures can result in an increase in the frequency of wildfires, which in turn result in increased levels of airborne particulate matter containing several other air pollutants, notably ozone and black carbon (a component of PM2.5) which can shift weather patterns and contribute to warming, particularly over areas covered in ice and snow.

The good news is that, while complex and requiring a coordinated government response, air pollution is a preventable and manageable threat. While air pollution has not been solved in any region - with the problem exacerbated in urban and industrial areas of low- and middle-income countries - many cities and countries around the globe have shown remarkable decreases in emissions and pollutant concentrations where strong policies, regulations and monitoring systems have been put into place. But air pollution knows no municipal or national borders. The air we breathe truly connects us all - addressing this threat in a sustainable manner requires urgent action and cooperation at all scales across the globe.

We, chief scientists at UNEP, WHO, IUCN, and WMO will contribute to a more integrated and systems-based approach to address air pollution by working more closely together at the international level to understand the scale of the problem; share information; identify gaps in the knowledge needed by countries to act and to encourage the agencies they represent to coordinate their efforts at national scale to reduce the air pollution threat more rapidly.

In that spirit, we call on researchers, industry leaders, decisionmakers and political leaders to work together to:

  • Continue to strengthen and expand cooperation at all scales on transboundary air pollution, particularly around integrated monitoring, reporting, and knowledge sharing of experiences and good practices. This includes strengthening and integrating policies, the capacity of institutions in all countries to develop the knowledge, tools, ground-based observations and data to implement effective policies to reduce air pollution.

  • Support development of a comprehensive global network of ground-based observations of atmospheric pollutants. Together with chemistry-transport models, a network involving scientific community, in coordination with UN agencies, to develop a clear picture of the global distribution of atmospheric pollutants, as well as the necessary set of guidelines to advise countries on how to deal with air pollution.

  • Identify co-benefits of action and prioritize policies that maximize synergies across multiple goals, national priorities and imperatives. The interlinkages between tackling air pollution, climate change mitigation, biodiversity conservation, food security, and development provide many opportunities to amplify the benefits of our actions and catalyse even greater mitigation ambition. Harnessing these will put the world on a trajectory that maximizes benefits, reduces the risk of policy failure, and delivers national development priorities.

  • Undertake specific science-based actions to manage air pollution, including for example:

    • National implementation of the WHO's air quality guidelines which would contribute to an 80% reduction of mortality caused by air pollution, a significant decrease in the burden of diseases and health costs to governments;

    • Solar and electric powering of health systems of all countries given the significant emissions of CO2 from this sector globally;

    • Implementation of the COP26 Health commitment which aims to achieve a Climate resilient and sustainable health system, creating the Alliance for Transformative Action on Climate and Health (ATACH) with more than 57 countries as part of the alliance and chaired by WHO;

    • Ploughing residual agricultural waste from a crop into the ground rather than burning it (responsible for a significant proportion of pollution in many parts of the world every year).

These are just a small few of the science-based actions that can be taken to manage air pollution while delivering simultaneous benefits for climate, public and ecosystem health, food security and sustainable development. For more resources for action, please refer to the following:

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