The epiphytic vegetation of <i>Populus balsamifera</i> and its significance as an air pollution indicator in Sudbury, Ontario

Abstract

Indices of atmospheric purity (IAP) of 31 sites, selected in the SO 2 -polluted as well as in the non-polluted areas around Sudbury were determined on the basis of number, frequency-coverage, and resistance factor of the epiphytes of Populus balsamifera. Based on these indices, arranged into convenient ranges, the investigated area was delimited into five different IAP zones. These zones were then compared with SO 2 pollution zones based on the ground-level average concentration of the gas prevailing in the area. From this comparison it is clear that the biological method provides a valid, quick, and economical way for assessing and mapping the long-range effect of pollution of a given area.