| Popis: |
The devastation of plant communities around some primitive smelters made it apparent even centuries ago that anthropogenic pollutants could severely damage forests. At first, it appeared that the effects of these pollutants diminished rapidly with increasing distance from their sources. However, as knowledge of plant communities increased, so did the realization that the effects of some pollutants were more widespread than was obvious. Over time, the emphasis of research on the impact of air pollutants on plants has shifted from the localized effects around point sources to the effects of regionally distributed pollutants. |
