National Trends in Nitrogen_Dioxide Concentrations in 1990 - 2014
| Year |
Mean |
Number of Trend Sites |
10th Percentile |
90th Percentile |
| 1990 |
76.3 |
91 |
46 |
120 |
| 1991 |
75.358608058608 |
91 |
44.5 |
110 |
| 1992 |
70.1919413919414 |
91 |
39 |
108 |
| 1993 |
68.4153846153846 |
91 |
44 |
90 |
| 1994 |
69.9208791208791 |
91 |
41 |
110 |
| 1995 |
68.5604395604395 |
91 |
35 |
100 |
| 1996 |
63.8291208791208 |
91 |
39 |
89 |
| 1997 |
62.1252747252747 |
91 |
37 |
93 |
| 1998 |
60.4739926739926 |
91 |
35 |
81 |
| 1999 |
64.3956043956044 |
91 |
35 |
96 |
| 2000 |
59.9673992673992 |
91 |
35 |
90 |
| 2001 |
58.3454212454212 |
91 |
33 |
80 |
| 2002 |
57.2296703296703 |
91 |
32.5 |
87 |
| 2003 |
56.2571428571428 |
91 |
35 |
81 |
| 2004 |
51.7249084249084 |
91 |
29 |
76 |
| 2005 |
51.2824175824175 |
91 |
29 |
75 |
| 2006 |
50.4388278388278 |
91 |
29 |
74 |
| 2007 |
49.3168498168498 |
91 |
29 |
66.3333333333333 |
| 2008 |
48.9666666666666 |
91 |
29 |
69 |
| 2009 |
44.3857142857143 |
91 |
25 |
63 |
| 2010 |
44.8194139194139 |
91 |
24 |
61.6 |
| 2011 |
43.9338827838827 |
91 |
24 |
62 |
| 2012 |
41.5666666666666 |
91 |
21 |
60.2 |
| 2013 |
41.4877289377289 |
91 |
21 |
59 |
| 2014 |
42.1098901098901 |
91 |
21 |
58.5 |