WHO global air quality guidelines

In 2021, WHO published the updated global Air Quality Guidelines, providing recommendations on air quality guideline levels as well as interim targets for six key air pollutants - particulate matter, ozone, nitrogen dioxide, sulphur dioxide and carbon monoxide. In addition, good practice statements are included. The new guidelines provide clear evidence of the damage that air pollution inflicts on human health, at even lower concentrations than previously understood. The guidelines identify the levels of air quality necessary to protect public health worldwide, and serve as a reference for assessing if, and by how much, the exposure of a population exceeds levels at which it causes health concerns. Achieving the recommended air quality guideline levels will deliver substantial health benefits glob-ally. For example, around 80% of premature deaths attributed to PM2.5 exposure in the world could be avoided if countries attain the annual guideline levels for PM2.5. Guideline levels for specified pollutants can be used as an evidence-informed reference to help deci-sion-makers in setting legally binding standards, and are a useful instrument with which to design effec-tive measures to achieve pollutant emission and concentration reductions, and therefore, to protect human health (93). μg = microgram, PM2.5 = fine particulate matter, PM10 = particulate matter, O3 = ozone, NO2 = nitrogen dioxide, SO2 = sulphur dioxide, CO = carbon monoxide, AQG = Air Quality Guideline. a. 99th percentile (i.e. 3–4 exceedance days per year). b. Average of daily maximum 8-hour mean O3 concentration in the six consecutive months with the highest six-month running-average O3 concentration. Note: Annual and peak season is long-term exposure, while 24 hour and 8 hour is short-term exposure.