| Averaging period | Limit value | Date by which limit is to be met | |
| 1. Hourly limit value for protection of human health | 1 hour | 350 µg m-3 not to be exceeded more than 24 times per calendar year | 1 January 2005 |
| 2. Daily limit value for protection of human health | 24 hours | 125 µg m-3 not to be exceeded more than 3 times per calendar year | 1 Jan 2005 |
| 3. Limit value for the protection of ecosystems | calendar year and winter (1 Oct - 31 Mar) | 20 µg m-3 | 2 yrs from entry into force of Directive |
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