Table 4.6 - Guideline values for exposure to ozone as set by WHO, EC and under discussion in UNECE for the protection of human health and vegetation (ppb)
Sources: WHO, 1987; EC Directive 92/72/EEC; UNECE, 1988
| Exposure duration | Protection of human health | Protection of vegetation | |||
|---|---|---|---|---|---|
|   | WHO | EC | WHO | EC | UNECE |
| 1 hour | 76100 | 88 | 100 | 100 | 75 |
| 8 hours | 5060 | 55* | - | - | 30 |
| 24 hours | - | - | 33 | 33 | - |
| Growing season (100 days) | - | - | 30 | - | - |
| Growing season (183 days), 9.0016.00 average | - | - | - | - | 25 |
Notes: * The 8-hour average is calculated as a moving average over the day, ie, it is calculated at every hour based on the 8-hourly values between minus one hour and minus nine hours before the reference time. For ozone (O3), 1 ppb ~ 2 µg/m3