What could be more exciting than watching grass grow? Monitoring plants for signs of air pollution! Certain plants serve as "bio-indicators." Like canaries in a coal mine, sensitive plant species warn us of conditions that could harm plants, animals, and even people. These are the plants that look like they have a rash or wither at the first sign of dirty air.

Some other plants are pollution-tolerant. If you find them in abundance in an area where there are no pollution-sensitive plants, it's a sure bet the air is dirty. Some of these amazing plants even remove toxins and improve air quality!

View these tracks to learn more about bioindicators, find out how to conduct field studies, and save the earth from pollution while there is still time! Read the questions in the annotations and find the answers in each track.

For a copy of the lesson, Student Worksheet, Field Study Report and assessment rubric that accompany this track, go to The Clean Air Campaign Web site (http://www.cleanaircampaign.com/Kids-Schools/Lesson-Plans) and click "Plants on Pollution Patrol."