The factors in the physical environment that are important to health include harmful substances, such as air pollution or proximity to toxic sites (the focus of classic environmental epidemiology); access to various health-related resources (e.g., healthy or unhealthy foods, recreational resources, medical care); and community design and the “built environment” (e.g., land use mix, street connectivity, transportation systems).
The environment can affect health through physical exposures, such as air pollution (OECD, 2012b). A large body of work has documented the effects of exposure to particulate matter (solid particles and liquid droplets found in the air) on cardiovascular and respiratory mortality and morbidity (Brook et al., 2010; Laumbach and Kipen, 2012; Mustafić et al., 2012; Tzivian, 2011). Research has identified specific physiologic mechanisms by which these exposures affect inflammatory, autonomic, and vascular processes (Brook et al., 2010; Tzivian, 2011).
The effects of particulate matter on mortality appear to be consistent across countries. For example, a recent review of studies from the late 1990s to mid-2000s found a consistent inverse relationship between airborne particulate matter and birth weight in Australia, Brazil, Canada, France, Italy, the Netherlands, South Korea, the United Kingdom, and the United States (Parker et al., 2011a). Another notable example is the evidence linking lead exposures to cognitive development in children (Bellinger, 2008; Levin et al., 2008). The evidence of environmental effects of air pollution and lead has been reflected in legislation in many countries directed at reducing levels of these pollutants in the environment.
Increasing attention has focused on the implications for health behaviors and social interactions that are created by the built environment. The
2Much early work on the spatial patterns of health used variables such as aggregate summaries of area socioeconomic or race/ethnic composition or measures of residential segregation by various attributes as proxies for a range of broadly defined environmental factors that may be relevant to health (see, e.g., Diez Roux and Mair, 2010). The identification of causal effects using these aggregate summaries raises a number of methodological challenges and does not allow one to identify the specific environmental attributes that may be relevant. More recent work has attempted to identify the specific environmental factors that may be important to specific health outcomes, as well as the pathways through which these factors may operate.
3The environment can also be considered on a larger geographic scale, especially in seeking explanations for cross-national health differences. For example, the health of some nations is affected by their geography or climate.
