One of the green terms we touched on briefly ( Define Your Terms - What is Green , September 19) is off-gassing , a major contributor to indoor air pollution. To restate the definition, off-gassing is the release of chemicals into the air from non-metallic materials. Paints, stains, building materials, even fabrics are capable of releasing volatile organic compounds (VOCs) and there is a long list of these chemicals although some are, as far as we know, harmless. One of the substances that is found...