WHO Air Quality Guidelines

In 2021, the World Health Organization (WHO) updated its global guidelines to offer quantitative health-based recommendations for air quality management, expressed as long or short-term concentrations for several key air pollutants. These guidelines are not legally binding, but they provide states with an evidence-informed tool that they can use to inform legislation and policy, and ultimately to help reduce levels of air pollutants and their related enormous health burden. Exceedance of the air quality guideline (AQG) levels is associated with serious risks to public health.

The guidelines were formulated by following a rigorous process to derive the lowest levels of exposure for which there is enough evidence of adverse health effects.

Table. Recommended air quality levels and interim targets.

Pollutant Averaging time Interim target AQG level
1 2 3 4
PM2.5, µg/m3 Annual 35 25 15 10 5
24-houra 75 50 37.5 25 15
PM10, µg/m3 Annual 70 50 30 20 15
24-houra 150 100 75 50 45
O3, µg/m3 Peak seasonb 100 70 - - 60
8-houra 160 120 - - 100
NO2, µg/m3 Annual 40 30 20 - 10
24-houra 120 50 - - 25
SO2, µg/m3 24-houra 125 50 - - 50
CO2, mg/m3 24-houra 7 - - - 4

a99th percentile (i.e. 3-4 exeedance days per year) bAverage of daily maximum 8-hour mean O2 concentration in six consecutive months with the highest six-month running-average O2 concentrations.

Source: WHO, 2021 https://apps.who.int/iris/bitstream/handle/10665/345329/9789240034228-en...

 

Last updated 2022-08-25