Air quality: new WHO guidelines

In recent days, the World Health Organisation (WHO) has published the new Global Air Quality Guidelines (AQGs), which set new limits for air quality. The new WHO guidelines recommend stricter limits (compared to the levels set in 2005) for six pollutants, the impacts of which on human health from exposure have been proven by numerous studies. These are PM10, PM2.5, ozone (O3), nitrogen dioxide (NO2), sulphur dioxide (SO2) and carbon monoxide (CO). For nitrogen dioxide (NO2), the annual average limits have been reduced to a quarter of what they were in 2005 (10 μg/m³), with a daily limit of 25 μg/m³; for PM 2.5, the annual limit has been halved to 5 μg/m³, with a new 24-hour limit of 15 μg/m³; and for PM10, the annual average limit has been reduced to 15 μg/m³, less than half the current regulatory limit in Europe. A new average limit for ozone of 60 μg/m³ and a new 24-hour limit for carbon monoxide (CO) of 4 μg/m³ have also been introduced.

WHO explains that the decision to tighten the limit levels is due to the fact that over the years there has been a marked increase in evidence showing that air pollution affects various aspects of health. In fact, it is estimated that every year exposure to air pollution causes 7 million premature deaths and the loss of millions of extra years of healthy life. According to WHO, “Improving air quality can enhance climate change mitigation efforts, while reducing emissions will in turn improve air quality.” Bearing in mind that air pollution is, together with climate change, one of the greatest environmental threats to human health, WHO’s choice becomes even more understandable.

While not legally binding, like all WHO guidelines, the AQGs are “An evidence-based tool for policy-makers to guide legislation and policies to reduce levels of air pollutants and decrease the burden of disease resulting from exposure to air pollution worldwide.”

The goal of the guidelines is that “All countries achieve the recommended air quality levels.” Aware that “This will be a difficult task for many countries and regions grappling with high levels of air pollution”, WHO has proposed “Intermediate targets to facilitate the gradual improvement of air quality and thus gradual but significant health benefits for the population.”