Characteristics of the reviewed studies
| Sachsen-Anhalt Study | Bitterfeld Study | Leipzig-Leipzig Study | |
| Areas | Magdeburg, Halle, Leipzig, Altmark (low pollution level) | Bitterfeld, Hettstedt, Zerbst (low pollution level) | Leipzig |
| Primary study goal | Estimation of chronic effects of air pollution | Estimation of chronic effects of air pollution | Trends of prevalence of atopy |
| Trends of prevalence of atopy | Trends of prevalence of atopy | ||
| Years of examination | 1991, 1992, 1993, 1994, 1995 | 1992–1993, 1995–1996, 1998–1999 | 1991–1992, 1995–1996 |
| Age of children yrs | 6–7 | 5–14 | 9–11 |
| Subjects n (total) | 14000 | 7500 | 3800 |
| Participation rate % | 64–96 | 75–89 | 82–88 |
| Residential history >2 yrs | yes | yes | no |
| Air pollution decline % | |||
| SO2 | 20–70 | 58–92 | 70 |
| TSP | 35–50 | 39–64 | 30 |
| Reference | 43 | 12–15, 47 | 46 |
SO2: sulphur dioxide
TSP: total suspended particles