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
