How can plants be used to measure the level of air polution?

Answer 1

Have you ever seen trees on the side of the street?

They must all be the same kind of plant or tree that you use so that you can compare them when the measuring is done.

Healthy trees = no or little pollution
Sick/stunted/dead trees = varying degrees of pollution

You could plant rows of trees close to sources of pollution (the easiest being streets, roads, and highways) and another row all by itself in a fieldAnswer:

Answer:

The study of the interaction of plants and pollution is generally called phytoxicology. In short it is the study of how various pollutants inpact a plants growth and health. As a n example the impact of sulfur dioxide in pine trees is that the needles turn red, and the impact of ethylene (a plant hormone frequently emitted as a by-product of industrial processes) on germinating plants is that they grow too quickly producing spindly stalks.

Biologists and toxicologists expose plats to these and other pollutants in carefully controlled experiments. The results can be used to estimate he levels of pollution that plants "in the wild" have been exposed to.