Parent document       Health effects of O3

Concentration [mg/m3] = [ppm]

Effect

60 - 80

Damaging effects on the leaves of sensitive trees

100 - 120

Respiratory difficulties in sensitive humans

150 - 160

Respiratory difficulties in most humans

> 300

Increased rate of mortality observed

Alert Levels
Level

Concentration

[ppb]

Pre-alarm

200

100

Alert Level 1

300

150

Alert-Level 2

400

200