aldehydes: a group of highly reactive chemical compounds used in making resins and dyes. Volatile organic compounds (VOCs). One of the better-known members of this group is formaldehyde.

Air Conditioning

(Also see HVAC). Two-thirds of all homes in the United States have air conditioners. Air conditioners use about 5% of all the electricity produced in the United States, at an annual cost of more than $11 billion to homeowners. As a result, roughly 100 million tons of...