Microbes are ubiquitous. We are exposed to them via the places we go, the people we meet, the food we eat, the water we drink and the air we breathe (the latter as components of bioaerosols). Together these different microbes constitute our environmental microbiome. This environmental microbiome can both protect against, and cause disease, in ways not yet fully understood. Only recently have we begun to appreciate the distinct microbial communities that exist within the environment and human body, and the subtle interactions between them that can shape our immediate, and future, health.