| Start of period during which the margin applies | End of period during which the margin applies | Benzene | Nitrogen dioxide (hourly limit value for the protection of human health) | Nitrogen dioxide (annual limit value for the protection of human health) |
|---|---|---|---|---|
| Coming into force of these Regulations | 31 December 2007 | 3 μg/m3 | 30 μg/m3 | 6 μg/m3 |
| 1 January 2008 | 31 December 2008 | 2 μg/m3 | 20 μg/m3 | 4 μg/m3 |
| 1 January 2009 | 31 December 2009 | 1 μg/m3 | 10 μg/m3 | 2 μg/m3 |