Air pollution takes on many forms. The tell-tale signs of pollution aren’t always as ominous as obscured buildings and killer smog. Sometimes it is a warm haze in the air that paints everything in a golden hue. Sometimes it is a smoky softness that hangs over a city. Whichever form, air pollution is always dangerous, with no safe level of exposure (3). Two main groups of air pollution exist. Gases come from a variety of sources, including transport, industry, soil, agriculture, and environmental conditions, and include ozone, sulphur dioxide and nitrogen oxides. Aerosols are grouped under one title: Particulate Matter (PM). PM is grouped by size in micrometres: PM10, PM2.5, and PM0.1. The different sizes lead to different effects; when breathed in, these particles, as they get smaller, can deposit further into the air sacs where oxygen and carbon dioxide move between blood and air.

When entering into the body, the immune system recognises these particles as foreign, and triggers inflammation. The cascade this starts can lead to heart attack and stroke. Besides these though, air pollution can also contribute to chronic lung diseases, cancer, diabetes, dementia, low birth weight, high blood pressure, and mental illness, with children being more susceptible to the effects of pollution (4)(5).

Air quality and pollution varies due to a number of factors, and the factors are unequally dispersed globally. In parts of Europe, environmental, energy and transport policies mean that the air can be relatively clean. In other parts of the world however, heavy industry and transport, lack of regulation and unfavourable environmental conditions can mean that pollution is inescapable and pervasive. In a lose-lose situation, poor outdoor air quality can be compounded by poor indoor air quality and can shorten lives by decades.

The World Health Organization (WHO) states guidelines which air pollution exposure should not exceed to protect health, and they have recently released new guidelines which set lower limits than previous (7). Many locations regularly exceed these figures through a normal day, and globally 92% of people live in areas that exceed these guidelines (8). Random sampling at the time of writing showed the level of PM2.5 exceeded the WHO limits in most European countries (9). An Air Quality Index (AQI) can also assess air quality and operates on a scale considering multiple pollutants that is country-specific (4).

The WHO states air pollution is a “major environmental risk to health” (9); 8.7 million people die prematurely per year (11). This is more than double the official death toll for the Covid-19 pandemic at the time of writing (12). Others have made this comparison between the pandemic, and the overlooked pollution pandemic, stating that what makes pollution risk so dangerous is its physical and political invisibility, its relative normalisation (8). Deaths are somewhat accepted as an unchangeable, inevitable outcome. More than 90% of these deaths are in low- and middle-income countries (8). Global analysis of exposure and excess mortality showed that the annual mean PM2.5 concentration in East Asia was just above 50, ten times the current WHO guidelines (8). At this exposure, it was reasoned that 30% of all deaths were related to air pollution; this is higher than the global average of 20% (8).

There is hope. While polluted areas were becoming more polluted, less polluted areas were becoming less polluted (10). People, cities, governments and organisations are starting to realise the massive impact of air pollution on society in some regions. It has helped that a very high-profile subject, Climate Change, is intimately linked to air quality, and efforts to reduce and legislate against an unstable climate, usually also work to improve air quality. Regulation and innovation are paving the way for more equitable, sustainable and air-friendly places to live; some cities are becoming greener, less energy intense and working to promote active and public transport. Energy production is shifting to focus on renewable energy, and away from fossil fuel combustion. Private innovation is raising awareness and informing people about the dangers, such as in London, where an app can inform your bicycle commute to account for local air quality (13). Transport is slowly becoming cleaner, with many European countries looking to a future without petrol and, importantly, diesel (the most significant source of PM0.1) (14).

The United Nations is pushing forward with the Sustainable Development Goals (SDGs) with air quality being linked to the Goals 3, 7, 11 and 13. The state of the atmosphere has received intense interest recently also with the recent publishing of the United Nations Intergovernmental Panel on Climate Change (IPCC) report about the state of the climate ahead of the COP26 conference in Glasgow in November. Given the inter-relationship between air pollution and Climate Change, the current level of discourse in governments, in the media, and in the societies of the planet are reassuring. We are seeing the widespread acceptance that the climate is changing due to human activity, and that more time is lost deciding what to do rather than acting, drawing us closer to irreversible climate changes. The time is ripe for action on air pollution, with society ready to embrace a future with cleaner air. The time is now to put pressure on individuals, organisations and governments to make sweeping changes to ensure the health of the planet going forward.

While sweeping changes from corporations, organisations and governments will be integral to improving the state of the climate, individuals can reduce air quality impact in their own way, such as using active or public transport for travel, using renewable sources of energy for electricity and travel (such as electric cars) and voting with their wallets to favour products and companies that have proved there are working to reduce their environmental impact. Information is available for those inspired to change, such as through supranational organisations, such as the United Nations Environmental Programme (15) and the One Planet Network (16), but also through NGOs such as Global Action Plan (17), and local Environmental Protection agencies.

Those concerned with the state of the planet, the environment, and the health of the people living on the planet should fight for clean air, and advocate for the reduction of air pollution in all forms. It is a dangerous, unnecessary harm that have been allowed to run rampant. The danger in the air isn’t always as ominous as fiery skies, gloomy horizons or obscured buildings. Memories from my childhood are filled with Australian summer days where the warmth seemed to hang in the air. Trips to Asian cities with a cold, light smog, or dusty afternoons in India and the Middle East, where the environment let me know that I was away from home on an adventure. Bright orange sunsets over endless hills exaggerating the layers of the landscape in the Balkans. While these memories are now seen in a different light, there is hope that the future will be cleaner, better and more sustainable. The timing has never been better to make the change.