Los Angeles started offering a $3.75 rebate on every square foot of grass replaced with a drought-friendly landscape. The drought is a boost in business for local conservation entrepreneurs. Frederic J. Brown/AFP/Getty hide caption

itoggle caption Frederic J. Brown/AFP/Getty

The Speck air quality monitor costs $200, but is available to all through Pittsburgh's public library system. Carnegie Mellon University CREATE Lab hide caption

itoggle caption Carnegie Mellon University CREATE Lab