Like Peanuts’ beloved Pigpen, we all carry around our own personal clouds of dust — only ours are invisible. A new study published in the journal PeerJ is the first to describe our “personalized microbial clouds” and their implications in the spread of infectious disease.

The University of Oregon team found that individuals emit a unique combination of aerosolized bacteria from their breath, clothes, skin, and hair. To study the extent of each microbial cloud’s uniqueness, the eleven participants were seated in individual sanitized experimental chambers. The microbes they emitted into the air around them were collected on air filters or on dishes as they settled and later sequenced for identification.

Bacteria are ubiquitous on human skin and within the body. The mouth-dwelling bacteria Streptococcus, together with Propionibacterium and Corynebacterium, which are normally found on the skin’s surface, were all found in the air surrounding the participants. What distinguished each person’s microbial cloud was the unique combination of bacterial families present.

Within four hours of sitting in a sanitized room, each participant could be identified by their personal microbe cloud.

As the authors point out, people living in industrialized nations spend up to 90 percent of their lives indoors, walking in and out of the microbial clouds of friends and strangers. By shedding light on how these clouds form and interact, the authors hope their work will help design better models for the spread of infectious diseases in buildings.