Air pollution is one of the biggest environmental threats to human health, alongside climate change.
On September 22, the World Health Organization published new guidelines for governments worldwide on controlling and improving air quality. WHO calls for decisive action to combat pollution and provides specific recommendations.
New WHO Global Air Quality Guidelines (AQGs) provide clear evidence of air pollution’s damage to human health at even lower concentrations than previously understood. The guidelines recommend new air quality levels to protect the health of populations, by reducing levels of key air pollutants, some of which also contribute to climate change.
The WHO now pays most attention to the health risks associated with particulate matter (PM) pollution caused by fossil fuel combustion. The carcinogenic effect of PM has been proven by numerous studies, which is also reflected in the official classification of the International Agency for Research on Cancer (IARC). The most dangerous PM emissions are generated by burning coal, as ash dust can contain a wide range of toxic substances, including heavy metals.
Why should we listen to WHO recommendations?
WHO calls on world governments to tackle two significant threats to public health – air pollution and climate change.
The new WHO guidelines set air quality standards for the concentrations of the six significant pollutants for which the most evidence of public health effects has been accumulated. Namely, the WHO recommendations relate to the prevention of air pollution by suspended particles (PM2.5 and PM10), ozone (O₃), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and carbon monoxide (CO). The WHO guidelines apply to both indoor and outdoor air around the world and cover all cases.
The WHO pays most attention to the health risks associated with suspended particles, the concentration of which is measured by two indicators: PM10 and PM2.5, which determine the mass content of particles with sizes equal to or smaller than 10 and 2.5 micrometers. Both PM2.5 and PM10 can penetrate deep into the airways, but PM2.5 can even enter the bloodstream, leading primarily to cardiovascular disease, lung damage, and other organs.
Weighted particles are formed mainly from the combustion of fossil fuels in various sectors, including transport, energy, household, industry, and agriculture. In 2013, the WHO International Agency for Research on Cancer (IARC) classified the effects of air pollution by suspended particles as carcinogenic, ie, a factor in the occurrence of cancer.
According to the WHO analysis, almost 80% of worldwide deaths due to exposure to PM2.5 could be prevented by reducing current levels of air pollution to those recommended in the updated guide. At the same time, achieving specific intermediate targets will also significantly reduce the burden of disease. Measures to reduce air pollution by these so-called classic pollutants also reduce the content of other harmful substances in the air. In the context of the current climate crisis, it is also important that this also reduces greenhouse gas emissions.
The WHO also guides on certain types of suspended particulates (e.g., black carbon / soot, ultra-fine particulate matter from sand and dust storms), for which there is currently insufficient quantitative evidence to establish indicative air quality indicators.
Like all WHO guidelines, air quality guidelines are not legally binding. Still, they are a science-based tool that policymakers can use to guide legislation and other regulations to reduce air pollution and reducing the burden of diseases caused by exposure to this contamination.
