Year | Lower than 10 000 (µg/m³)•h | 10 000-20 000 (µg/m³)•h | 20 000-30 000 (µg/m³)•h | 30 000-50 000 (µg/m³)•h | Greater than 50 000 (µg/m³)• h |
---|---|---|---|---|---|
2004 | 2 | 49.3 | 20.1 | 21.3 | 7.2 |
2005 | 24.7 | 18 | 18.9 | 28.7 | 9.7 |
2006 | 0.2 | 31.8 | 18 | 39.8 | 10.2 |
2007 | 40.3 | 14.6 | 13.6 | 24.5 | 6.9 |
2008 | 21.7 | 31.2 | 21.5 | 25.1 | 0.5 |
2009 | 34.7 | 19.3 | 18.4 | 24.2 | 3.3 |
2010 | 38.9 | 15.1 | 25.1 | 19 | 2 |
2011 | 32.9 | 16.3 | 25.8 | 21.9 | 3 |
2012 | 36.7 | 18.7 | 18.2 | 22.9 | 3.6 |
2013 | 34.4 | 24.2 | 19.3 | 18.3 | 3.7 |