The word green conjures images of a lush, vibrant ecosystem that is full of healthy living things and fresh air. Green buildings are typically thought of as those that use minimal resources to construct and operate and cause as little negative environmental impact as possible. Though providing for an indoor environment that attempts to mimic an ideal ecosystem is typically a part of green buildings, it is not always achieved.
During the 1970s energy crisis, the trend was to seal up buildings (e.g., no more openable windows and more airtight envelopes) and reduce outdoor air intake to save energy. This contributed to what was termed “sick building syndrome” or “tight building syndrome.” It seems that some of those mistakes of the past are being repeated.