YEARS

MEAN CONC of CH₄ (ppm)

Standard deviation (SD) of CH₄

Standard error (SE) of CH₄

MEAN CONC of O₃ (ppm)

Standard deviation

(SD) of O₃

Standard error of O₃

MEAN CONC of NO₂ (ppm)

Standard deviation (SD) of NO₂

Standard error of NO₂

2003

1723.946

21.91

6.32

56.1647

2.06

0.59

94.12148

38.73

11.18

2004

1729.728

13.87

4.00

57.3319

2.17

0.63

92.64547

43.99

12.70

2005

1730.286

8.37

2.42

54.4281

1.27

0.37

90.64494

42.17

12.17

2006

1722.223

14.28

4.12

57.1586

3.35

0.97

91.46054

40.41

11.67

2007

1732.921

15.46

4.46

55.2187

1.42

0.41

83.15172

35.36

10.21

2008

1736.170

14.23

4.11

58.6802

2.96

0.85

83.13088

33.12

9.56

2009

1742.412

12.27

3.54

57.1286

2.12

0.61

85.11320

33.911

9.79

2010

1740.400

7.33

2.12

58.1763

3.43

0.99

76.38385

41.53

11.99

2011

1752.255

21.23

6.13

58.3196

1.61

0.46

86.42268

31.58

9.12

2012

1767.420

13.77

3.97

56.7783

1.75

0.50

78.80879

33.43

9.65