The fourth and final installment of our series on the original four Greek elements: Earth, Water, Fire, and Air. Segments include a history of the air we breath – how it was formed and how it’s changing over time. Plus a feature from WABE reporter Jim Burress on how volatile organic compounds and tailpipe emissions combine to make a “toxic soup” and how furniture and carpet manufacturers are changing their products to make our air healthier.

New York Skyline image courtesy of Flickr user Sev!.