Gas exchange is a critical process required for sufficient tissue perfusion. The environment, genetics, or a combination of the two can affect this process. Various strategies have evolved to overcome the specific gas exchange challenges in different environments and it is clear that some genes are pivotal to the development of gas exchanging organs (e.g. Bmp4). Lower partial pressure of oxygen (hypoxia), reducing the partial pressure gradient, makes gas exchange more challenging and therefore the height to which gas exchangers can travel above sea level is limited. However, some human populations (e.g. Tibetans) and other animals (e.g. Bar-headed goose) have adapted well to profoundly hypoxic conditions, suggesting genetic factors are important. Gas exchange can also be affected by air pollution, including particulate matter and ozone among others, and exposure can lead to cardiopulmonary responses depending on individual susceptibility or preexisting disease, both of which have genetic and environmental components. Diseases that affect gas exchange include, but are not limited to, pulmonary hypertension, chronic obstructive pulmonary disease (COPD), and bronchopulmonary dysplasia. Moreover, different species successfully exchange gases in their specific environment, for example animals that fly or burrow. Under these conditions, common genetic mechanisms, and their interaction with environment, help to maintain, or are detrimental to, gas exchange.