next
previous
items

World Health Organization (WHO) air quality guidelines (AQGs) and estimated reference levels (RLs)

Page Last modified 26 Jan 2023
1 min read
Photo: © Tolu Olarewaju on Unsplash

World Health Organization (WHO) air quality guidelines (AQGs) and estimated reference levels (RLs) (a)

 

PollutantAveraging periodAQGRLComments
PM10 1 day


Calendar year
45μg/m3


15μg/m3
99th percentile (3-4 exceedance days per year). Updated 2021 guideline

Updated 2021 guideline
PM2.5 1 day


Calendar year
15μg/m3


5μg/m3
99th percentile (3-4 exceedance days per year). Updated 2021 guideline

Updated 2021 guideline
O3 Maximum daily 8-hour mean


Peak season (b)
100μg/m3



60μg/m
3
99th percentile (3-4 exceedance days per year). New 2021 guideline

New 2021 guideline

NO2 1 hour
1 day



Calendar year
200μg/m3
25μg/m3



10μg/m
3

99th percentile (3-4 exceedance days per year). New 2021 guideline

Updated 2021 guideline
BaP Calendar year 0.12ng/m3
SO2 10 minutes

1 day
500μg/m3

40μg/m
3


99th percentile (3-4 exceedance days per year). New 2021 guideline


CO 1 hour

Maximum daily 8-hour mean

1 day
30mg/m3

10mg/m
3


4mg/m
3





99th percentile (3-4 exceedance days per year). 
New 2021 guideline
C6H6 Calendar year 1.7μg/m3
Pb Calendar year 0.5μg/m3
As Calendar year 6.6ng/m3
Cd Calendar year 5ng/m3 (c)
Ni Calendar year 25ng/m3

 

Notes: 
(a) As WHO has not set an AQG for BaP, C6H6, As and Ni, the RL was estimated assuming an acceptable risk of additional lifetime cancer risk of approximately 1 in 100 000.

(b)  Average of daily maximum 8-hour mean concentration in the six consecutive months with the highest six-month running average O3 concentration.

(c) AQG set to prevent any further increase of Cd in agricultural soil, likely to increase the dietary intake of future generations.

Sources: 
WHO (200020062021). 

Permalinks

Geographic coverage

Tags

Filed under:
Filed under: air quality
Document Actions