Office sprawl has huge environmental consequences. Downtown locations are more efficient, but pose problems of their own, such as urban heat islands.

A future with clean air and a stable climate hinges on our ability to cut energy use and rely more heavily on renewable sources.

Building materials can cost a lot: forest destruction, waste, pollution. But products made with sustainably harvested wood and recycled materials save natural resources.

The environment isn't only outside. Indoors, too, people deserve clean air and access to the beauties of nature.