against some pollutants that are of predominantly outdoor origin; but that protection is generally incomplete. And some outdoor pollutants that enter a building interact with its components or contents and thereby alter the composition of indoor air in ways that can affect the health and welfare of occupants.
Climate change has the potential to affect the indoor environment. Ambient conditions in the outdoor environment serve as boundary conditions to the ambient conditions of the indoor environment. Outdoor air temperature, humidity, air quality, precipitation, and land surface wetness can all influence the indoor environment, depending on such factors as the integrity of a building’s envelope; the state of its heating, ventilation, and air-conditioning systems; the inhabitants of the outdoor ecosystem; and the characteristics of the buildings around it. If climatic conditions in a particular area change—for example, if the climate becomes warmer or if there are more severe or more frequent episodes of high heat or intense precipitation—buildings (and other infrastructure) that were designed to operate under the “old” conditions may not function well under the “new.” Furthermore, in responding to climate changes, people and societies will seek to mitigate undesirable changes and adapt to changes that cannot be mitigated. Some of their responses will play out in how built spaces are designed, constructed, used, maintained, and in some cases retrofitted, and the actions taken may well have consequences for indoor environmental quality and public health.
There is a body of literature on how the indoor environment influences occupant health and how the external environment influences the internal built environment under past and present climate conditions. And research is emerging on the possible effects of climate change—such as extreme temperatures and thermal stress, vectorborne infectious diseases, and outdoor air quality—on human health. However, the body of research specific to the effects of climate change on human health in the indoor environment is very small. Such studies are complicated by the fact that the effects of climate change on, say, indoor air quality depend on the geographic region and are a function of the age and condition of the regionally dependent built environment.
Against that backdrop, the US Environmental Protection Agency (EPA) approached IOM with a request to summarize and benchmark the state of the science concerning the health effects of climate change–induced alterations in the indoor environment, raise awareness of crucial issues, and suggest a way forward. The Committee on the Effect of Climate Change on Indoor Air Quality and Public Health was formed to respond to that request.