This symposium seeks to present work in progress in an important area that is new to environment-behavior research in order to initiate a discussion on the impact of design on human health. In particular, we will focus on the human microbiome and the impact of environmental design, at a large and small scale, on the makeup and diversity of microbes from the environment or commonly found in humans.

The microbiome is important in human physiology. It plays important roles in organ functions, from immunity to angiogenesis, endocrine physiology, food digestion, vitamin production, and colonization resistance to pathogens. It coevolved with the complex life forms that developed after bacteria. Most of the human evolutionary time (~100,000 years) saw the coevolution of the microbiota and Homo sapiens within pre-urban and pre-technological ancestral lifestyles. The changes associated with modern life, including urbanization and technological advances have brought with them changes in our microbiome, and this disruption in has been recently associated with currently increasing diseases.

The cultural creation of built environments with specific uses have consequences that are not fully understood, particularly concerning the extent to which: (1) the environment shapes the respective biomes of the building and the occupants, and (2) the occupants’ behaviors affect microbial transmission between humans and indoor surfaces. Urbanization and modernization of buildings has meant tighter building envelopes and higher control over temperature, humidity and ventilation, which results in greater separation between indoor and outdoor environments. The use of spaces has also changed with modernization, in general, decreasing occupant density, while increasing use of cleaning products. Urban household environments are converging towards habitats that are isolated from outdoor environments and in which human microorganisms, rather than environmental ones, may dominate.

The research reported in this symposium shows recently found associations between modernization in buildings and the impact it has on the microbial communities of the buildings and their occupants.

Microbial samples and related environmental data on buildings and their occupants have been collected for four villages in the Amazon Basin of Peru and Brazil, in an increasing gradient of urbanization, from dwellings in an extremely isolated village in the Amazon rain forest to a major metropolitan area along the same latitude. We are interested in environmental and behavioral factors (including urbanism, architectural characteristics, environmental quality, diet, inter-personal contact), that may affect the human microbiome across the urbanization gradient. Parameters that characterize houses and their environmental context were collected in 10 houses from all four communities, including indoor and outdoor temperatures and relative humidity, light intensity, particle concentrations, and several parameters characteristic of buildings, such as air exchange rate, surface temperatures, and moisture content in wood and stucco walls. Parameters that more precisely characterize the occupants, including personal temperature and humidity were used to evaluate the conditions of human skin over the daily activity cycle. Samples of microbes from building occupants, home pets, building materials, and home objects were collected to assess the influence that urbanization level and corresponding environmental conditions have on microbial communities found on people and surfaces (detected by gene sequencing). Preliminary results show that changes in the use of home space and architecture lead to altered environmental parameters, ventilation rates, and building materials. Initial analyses of the human microbiome show differences across the transculturation gradient.

While this work has been presented to and discussed among microbiologists, it has not reached the attention of environment-behavior researchers. Our goal is to use this symposium to begin a discussion about the meaning and impact of this area of research for urban researchers and designers.

Other researchers who have contributed to this project include: Atila Novoselac Jean Frances Ruiz-Calderon, Rafael Rios, Luis Pericchi, Martin Blaser, Oralee Branch, Jean Hernandez, Henrique Pereira, Luciana Campos, Jose Clemente, Rob Knight.