Tab. IV.4.1 Air quality index based on concentrations of pollutants

Index Air quality NO2
hourly concentration
[µg.m-3]
O3
hourly concentration
[µg.m-3]
PM10
hourly concentration
[µg.m-3]
1 very good 0–25 0–33 0–20
2 good > 25–50 > 33–65 > 20–40
3 fair > 50–100 > 65–120 > 40–70
4 suitable > 100–200 > 120–180 > 70–90
5 poor > 200–400 > 180–240 > 90–180
6 very poor > 400 > 240 > 180