Table 4.2 - WHO air quality guidelines for relevant pollutants and expected effect concentrations

Source: Based on WHO, 1987

Pollution type Indicator AQG (µg/m3) Averaging time Effect level Effects
Short term effects
Summer smog O3 150­200 1 hour 200 µg/m3; classification: mild Lung function decrements, respiratory symptoms, inflammation
Winter smog SO2 + PM1 125 + 125 1 day 400 µg/m3; classification: moderate Decreased lung function; increased medicine use for susceptible children
Urban/traffic NO2 150 1 day ­ ­
Long term effects
Traffic/industry Lead 0.5­1.0 1 year ­ Effects on blood formation, kidney damage; neurologic, cognitive effects
Combustion SO2 + PM1 50 + 50 1 year   Respiratory symptoms, chronic respiratory illness

Note:

1 Particulate matter measured as black smoke