Can trees serve as indicators for vapor intrusion?

The air in houses can be affected by bad stuff, called contaminants. Sometimes harmful chemicals enter the air in buildings from nearby contaminated soil and groundwater through cracks or gaps in the foundation – a process known as vapor intrusion. Scientists wanted to find out if trees can serve as indicators for vapor intrusion.  What can trees tell us about the air we breathe at home?  This image is being used to spark the interest in finding the answer to these questions.