Since part of the purpose of LEED is to reduce the pollution created by buildings, guidelines that reduce energy consumption make sense. But when reading through the LEED guidelines, it might surprise you to learn that the program awards points for steps that improve the interior air quality of a building, too. For example, if you add air filtration and moisture control systems to help reduce molds and allergens, you can score points. There are also some health and safety guidelines, like preventing HVAC vents from connecting between garages and living areas, and making sure there are exhaust vents installed in kitchens. Other guidelines are more focused on personal comfort, including a prerequisite requiring LEED-certified homes to have even heating and cooling throughout the house [source: U.S. Green Building Council]. But what does a person's comfort have to do with helping the environment? According to the USGBC, the air quality inside is usually worse than the air quality inside, and can lead to health problems just like air pollution can [source: U.S. Green Building Council].