Lawrence Berkeley National Laboratory

As is becoming increasingly clear, the human species evolved in the East African savannah. Details of the precise evolutionary chain remain unresolved however it appears that the process lasted several million years, culminating with the emergence of modern Homo sapiens roughly 200,000 years ago. Following that final evolutionary development modern Homo sapiens relatively quickly populated the entire world. Clearly modern Homo sapiens is a successful, resourceful and adaptable species. In the developed societies, modern humans live an existence far removed from our evolutionary ancestors. As we have learned over the last century, this "new" lifestyle can often result in unintended consequences. Clearly, our modern access to food, shelter, transportation and healthcare has resulted in greatly expanded expected lifespan but this new lifestyle can also result in the emergence of different kinds of diseases and health problems. The environment in modern buildings has little resemblance to the environment of the savannah. We strive to create environments with little temperature, air movement and light variation. Building occupants often express great dissatisfaction with these modern created environments and a significant fraction even develop something akin to allergies to specific buildings (sick building syndrome). Are the indoor environments we are creating fundamentally unhealthy -- when examined from an evolutionary perspective?