Air pollution is one of the biggest environmental and health problems in the world. An estimated 9% of deaths globally are attributed to it, making it the 4th biggest risk factor on the planet. Up to seven million people die prematurely every year because of air pollution, according to WHO estimations.

For the first time since 2005, the World Health Organization (WHO) strengthened its air quality guidelines, calling on governments to take urgent action on reducing pollution and improving air quality.

The new guidelines provide “clear evidence” of the damage caused by air pollution on human health, at even lower concentrations than previously understood, the WHO said. They recommend new air quality levels that are necessary to protect the health of populations, which, if followed, could save millions of lives on a global scale. 

Almost all air quality guidelines (AQG) levels were adjusted downwards, as there has been an increase of evidence over the health effects of air pollution. With climate change, air pollution is one of the most significant environmental threats to human health. Every year, millions die prematurely or loose months of life because of it. 

In adults, stroke and heart disease are the most common causes of premature death linked to outdoor air pollution, with growth evidence of other effects such as diabetes. In children, the list also includes respiratory infections, asthma and reduce lung growth. This puts air pollution on a par with other global health risks such as smoking. 

“Air pollution is a threat to health in all countries, but it hits people in low- and middle-income countries the hardest,” WHO Director-General, Dr Tedros Adhanom Ghebreyesus, said in a media statement. “The new guidelines are an evidence-based and practical tool for improving the quality of the air on which all life depends.”

The key pollutants

The guidelines recommend air quality levels for pollutants such as carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), and particulate matter (PM). The risks of particulate matter equal to or smaller than 10 and 2.5 microns in diameter are particularly relevant, as these particles can penetrate into the lungs and enter the bloodstream. 

These small airbone particles are mainly generated by fuel combustion in different sectors, such as energy (fossil fuels), agriculture, wildfires, and transportation. Some particles such as smoke or dirt, are dark or big enough in order to be seen with the naked eye, while others are so small that can only be seen with a microscope. 

The new guidelines say that annual PM2.5 concentrations shouldn’t be higher than 5 micrograms per cubic meter, which is half the limit that was being used until now. This is because it’s becoming clearer that long exposure to concentrations even that low can contribute to negative health impacts, such as heart and lung diseases and stroke.

In fact, a study earlier this year showed that the average global citizen loses 2.2 years of life with the current levels of air pollution. We are all exposed to more than three times the air pollution considered acceptable by the WHO, with life expectancy declining from 74 to 72 years. Southeast Asia is one of the most affected regions. 

“Annually, WHO estimates that millions of deaths are caused by the effects of air pollution, mainly from noncommunicable diseases. Clean air should be a fundamental human right and a necessary condition for healthy and productive societies.,” WHO Regional Director for Europe, Hans Henri Kluge, said in a media statement. 

The new guidelines come almost a month away from the COP26 climate change summit in the United Kingdom. The WHO climate change head Maria Neira told reporters in a press conference that they are getting ready for a report to highlight the “enormous health benefits” of reducing air pollution through climate change mitigation.