Table 2 Development of average air quality and hypertrophication index values in Wetzlar and Giessen from 1985 to 2010
Year | Average air quality index value (first digit), Wetzlar | Average air quality index value (first digit), Giessen | Average hypertrophication index value (second digit), Wetzlar | Average hypertrophication index value (second digit), Giessen |
|---|---|---|---|---|
1985 | 2.1 | 1.1 | 1.2 | 1.0 |
1995 | 2.6 | 1.4 | 1.5 | 1.3 |
2005 | 3.1 | 2.4 | 2.3 | 1.6 |
2010 | 3.4 | 3.3 | 2.4 | 2.5 |