Table 1: Comparison of the WHO guidelines and standards from different countries. Modified from WHO air quality guidelines, global update, 2005, a report on a Working Group meeting, Bonn, Germany, 18–20 October 2005 [5].

Selected air quality guidelines and standards
Source PM10 (μg/m3)PM2.5 (μg/m3)
1 year24 hours1 year24 hours

WHO [2]20501025
European Union405025
United States501501235
California20501565
Japan1001265
Brazil50150
Mexico501201565
South Africa601801565
India (sensitive populations/
residential/industrial)
50/60/120
China
(Classes I/II/III)
40/100/15050/150/25035