Up until 25 years ago, indoor air pollution was a very limited phenomenon. Since that time, two basic things have changed in the way that we build our buildings. First, we have introduced thousands of chemicals into our building materials. Second, we have sealed our buildings so tightly that the chemicals remain trapped inside our homes, where we inhale them into our lungs and absorb them through our skin. Before the energy crisis, the typical home averaged approximately one air exchange per hour. Now, in a well sealed home, the air is often exchanged as little as once every five hours or longer, and that is not enough to ensure healthful air quality.
In recognition of the problem, two basic schools of thought have arisen as to how to solve this problem. The first approach involves eliminating as many pollutants as possible from within the building envelope and sealing it very tightly on the inside so that there is less need to worry about the chemical composition of either the structure or the insulation. Clean, filtered air is then mechanically pumped in, keeping the house under a slightly positive pressure so that air infiltration is controlled. Thus the resident isolates himself from a toxic world. If you do not have the luxury of clean, vital, and refreshing natural surroundings, then a certain amount of isolation and filtering may be essential.
The second school of thought involves building the structure out of natural or non-toxic materials that "breathe." Double adobe with natural insulation in the cavities, straw/clay, and straw bale are some examples of building systems that would fall into this category. The building is seen as a third skin (our clothes being the second skin). As such, the building is viewed as a permeable organism interacting with the natural world around us and facilitating a balanced exchange of air and humidity. This approach is based on the precepts of Baubiology. On a philosophical level, we find this approach more appealing because it is based on an interactive relationship with the surrounding environment. We believe that, in terms of the larger ecological picture, our survival as a species is dependent on interaction and linking rather than isolationism.
Sealed construction is a relatively new concept, as new as the invention of plastic. Throughout the history of mankind we have sheltered ourselves in breathable structures. Ironically though, if you intend to apply for a building permit, many of the "breathing" wall building systems will either not be permitted, or they will be permitted only as experimental structures. This is because our recent building codes have been based on "sealed" construction.
Whereas in the first approach the home is isolated from a toxic world, in the second approach the home is interactive with the surrounding environment. One approach strives to create a healthy environment through technology, the other through a return to nature. Much of the information in this book is applicable to either approach since the purpose is to identify and eliminate sources of indoor air pollution commonly found in the home. Although our emphasis will be on home construction, many of the same problems and solutions apply to our schools and places of work.
In recognition of the problem, two basic schools of thought have arisen as to how to solve this problem. The first approach involves eliminating as many pollutants as possible from within the building envelope and sealing it very tightly on the inside so that there is less need to worry about the chemical composition of either the structure or the insulation. Clean, filtered air is then mechanically pumped in, keeping the house under a slightly positive pressure so that air infiltration is controlled. Thus the resident isolates himself from a toxic world. If you do not have the luxury of clean, vital, and refreshing natural surroundings, then a certain amount of isolation and filtering may be essential.
The second school of thought involves building the structure out of natural or non-toxic materials that "breathe." Double adobe with natural insulation in the cavities, straw/clay, and straw bale are some examples of building systems that would fall into this category. The building is seen as a third skin (our clothes being the second skin). As such, the building is viewed as a permeable organism interacting with the natural world around us and facilitating a balanced exchange of air and humidity. This approach is based on the precepts of Baubiology. On a philosophical level, we find this approach more appealing because it is based on an interactive relationship with the surrounding environment. We believe that, in terms of the larger ecological picture, our survival as a species is dependent on interaction and linking rather than isolationism.
Sealed construction is a relatively new concept, as new as the invention of plastic. Throughout the history of mankind we have sheltered ourselves in breathable structures. Ironically though, if you intend to apply for a building permit, many of the "breathing" wall building systems will either not be permitted, or they will be permitted only as experimental structures. This is because our recent building codes have been based on "sealed" construction.
Whereas in the first approach the home is isolated from a toxic world, in the second approach the home is interactive with the surrounding environment. One approach strives to create a healthy environment through technology, the other through a return to nature. Much of the information in this book is applicable to either approach since the purpose is to identify and eliminate sources of indoor air pollution commonly found in the home. Although our emphasis will be on home construction, many of the same problems and solutions apply to our schools and places of work.