Chemistry Reference
In-Depth Information
Table 4 Trend analysis for 29 EMEP monitoring stations over the 1993-2009 period ranked in
order of their extrapolated 1990 levels
Station
Slope, ppb per year
1990 level, ppb
Significance level
GB0039R
1.6
1.4
101
15
a
¼
0.1
SI0032R
0.7
96
a
>
0.1
DE0008R
0.7
0.7
95
8
a
¼
0.05
CH0005R
0.2
94
a
>
0.1
CZ0001R
1.3
1.3
92
11
a
¼
0.05
BE0001R
0.9
93
a
>
0.1
BE0032R
0.5
91
a
>
0.1
GB0014R
1.7
1.5
91
7
a
¼
0.01
DE0007R
0.5
89
a
>
0.1
CH0004R
0.3
88
a
>
0.1
CZ0003R
0.6
88
a
>
0.1
AT0042R
0.6
0.6
87
6
a
¼
0.1
AT0038R
0.4
87
a
>
0.1
AT0044R
0.5
86
a
>
0.1
0.4
a
>
0.1
AT0040R
85
GB0037R
1.0
85
a
>
0.1
SI0031R
0.7
84
a
>
0.1
AT0030R
0.0
84
a
>
0.1
SI0033R
0.5
84
a
>
0.1
DK0041R
1.0
1.0
82
12
a
¼
0.05
DE0009R
1.0
0.7
81
6
a
¼
0.05
DK0031R
0.4
79
a
>
0.1
SK0004R
0.2
78
a
>
0.1
SK0007R
0.1
73
a
>
0.1
SK006R
0.3
70
a
>
0.1
LT0015R
0.3
69
a
>
0.1
LV0010R
0.4
67
a
>
0.1
SE0013R
0.2
61
a
>
0.1
CH0001G
0.2
59
a
>
0.1
Notes
: the confidence limits on the Sen's slope estimates are shown as 2-
intervals
s
17 stations showed downwards trends that were not highly statistically significant
(
0.1) and 5 stations showed slightly positive trends that were not highly
statistically significant (
a
>
a
>
0.1). Five stations showed highly statistically signifi-
cant (
1 ppb per year and these were
GB0039R Sibton, CZ0001R Svratouch, GB0014R High Muffles, DK0041R Lille
Valby and DE0009R Zingst. Again, there was a clear tendency for the stations with
the largest annual values extrapolated back to 1990 to show the largest downwards
trends. Those stations with the smallest 1990 values tended to show slightly positive
trends that were not highly statistically significant (
a
0.1) downwards trends that exceeded
0.1).
Table
5
summarises the trends over the 2000-2009 period for those 13 stations
that showed highly statistically significant (
a
>
0.1) downwards trends. There were
an additional 65 stations that showed no highly statistically significant (
a
0.1)
trends at all. The station in Table
5
which exhibited the largest downwards trend of
a
>
