Every day, some 93% of the world’s children under the age of 15 years are breathing polluted air that puts their health at risk, a new report from the World Health Organization (WHO) concludes.

“Polluted air is poisoning millions of children and ruining their lives,” says Dr Tedros Adhanom Ghebreyesus, WHO Director-General. “This is inexcusable. Every child should be able to breathe clean air so they can grow and fulfil their full potential.”

In an increasingly populated, increasingly developed world, we are using more and more resources, and that’s taking an increasingly high toll on the quality of our atmosphere — on one hand, we have rising temperatures fueled by our burning of fossil fuels, and on the other hand, we have the associated air pollution.

Now, a new WHO study brings to light a new problem: way too many of the world’s children are breathing polluted air. This is not a new finding, but the scale at which it is happening is shocking.

“Air pollution is stunting our children’s brains, affecting their health in more ways than we suspected,” said Dr Maria Neira, WHO director of public health and the environment.

The report estimates that in 2016 alone, 600,000 children died from acute lower respiratory infections caused by polluted air, and overall, polluted air accounts for a third of deaths from stroke, lung cancer and heart disease. Children are most vulnerable to it.

Overall, 93% of the world’s children are exposed to one of the most damaging pollutants — PM2.5. PM2.5 (also called Fine Particulate Matter) is defined as pollutant with a diameter smaller than 2.5 µm (with 1 µm being 0,001 mm). Because it is so small, PM2.5 is particularly dangerous, as it can infiltrate quite deep inside someone’s lungs, and even in the bloodstream.

According to the EPA, numerous scientific studies have linked particle pollution exposure to a variety of problems, including:

• premature death in people with heart or lung disease;
• nonfatal heart attacks;
• irregular heartbeat;
• aggravated asthma;
• decreased lung function;
• increased respiratory symptoms, such as irritation of the airways, coughing or difficulty breathing.

Although the vast majority of children is breathing air above the pollution threshold recommended by the WHO, there is a strong divide based on country income: 98% of children under 5 from under-developed or developing countries are breathing unsafe air, compared to only 52% of children from the developed world.

But this is certainly not a problem restricted to some parts of the world — it’s something that the entire world needs to solve, together.

The WHO calls all the world’s countries to adhere to global air quality guidelines in order to enhance the health and safety of children. First of all, we need a better understanding and monitoring of pollution.  Low-cost sensors and other new technologies can expand air quality monitoring and forecasting to areas that are currently underserved. New protocols and standards are needed to guide the effective use and interpretation of data produced by low-cost sensors in citizen science and other applications, the WHO explains.

But at the end of the day, we need drastic changes in society, especially when it comes to reducing our dependency on fossil fuels. Things like moving schools and playgrounds away from sources of air pollution can make a temporary difference, but for a sustainable change, that’s just not gonna cut it. The organization writes:

“To achieve this, governments should adopt such measures as reducing the over-dependence on fossil fuels in the global energy mix, investing in improvements in energy efficiency and facilitating the uptake of renewable energy sources. Better waste management can reduce the amount of waste that is burned within communities and thereby reducing ‘community air pollution’. The exclusive use of clean technologies and fuels for household cooking, heating and lighting activities can drastically improve the air quality within homes and in the surrounding community.”

Air pollution affects neurodevelopment, leading to lower cognitive test outcomes, negatively affecting mental and motor development. Even low levels of exposure can lead to lung damage, with potentially devastating consequences.

There are two main types of air pollution: ambient air pollution (or basically outdoor pollution), which generally comes from fuel combustion in cars, power plants, industry or burning, and household air pollution (or indoor pollution), generated by a household’s combustion of fuels like coal, wood or kerosene, using open fires or basic stoves in poorly ventilated spaces. Both contribute to health problems, and both can be addressed by environmentally-friendly measures.