West Trends in Nitrogen_Dioxide Concentrations in 2000 - 2015
| Year |
Mean |
Number of Trend Sites |
10th Percentile |
90th Percentile |
| 2000 |
58.5 |
56 |
30 |
92 |
| 2001 |
58.3839285714285 |
56 |
28 |
96 |
| 2002 |
56.6309523809523 |
56 |
29 |
87 |
| 2003 |
56.4970238095238 |
56 |
31 |
88 |
| 2004 |
51.6220238095238 |
56 |
25 |
80 |
| 2005 |
49.8303571428571 |
56 |
27 |
77 |
| 2006 |
49.9017857142857 |
56 |
27 |
79 |
| 2007 |
48.1428571428571 |
56 |
24 |
72 |
| 2008 |
48.4196428571428 |
56 |
25 |
71 |
| 2009 |
43.2508928571428 |
56 |
21 |
63.5 |
| 2010 |
42.0619047619047 |
56 |
22 |
63 |
| 2011 |
41.8443452380952 |
56 |
19 |
62 |
| 2012 |
41.585119047619 |
56 |
18 |
61.1 |
| 2013 |
41.5065476190476 |
56 |
18 |
59.6 |
| 2014 |
40.7744047619047 |
56 |
15 |
59.1 |
| 2015 |
37.7124999999999 |
56 |
12 |
55.7 |