Year Lower than 10 000 µg/m³.h 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 Greater than 50 000 (µg/m³)•h
1996
1997
1998
1999
2000
2001
2002
2003
2004 2.03 49.34 20.13 21.31 7.19
2005 24.69 18.01 18.92 28.73 9.65
2006 0.2 31.75 17.99 39.81 10.24
2007 40.32 14.65 13.59 24.53 6.92
2008 21.74 31.23 21.48 25.06 0.5
2009 34.71 19.33 18.39 24.22 3.35
2010 38.9 15.08 25.06 18.99 1.97
2011 32.92 16.33 25.82 21.94 2.98
2012 36.68 18.68 18.18 22.87 3.59