Fig. 1
From: Sources of airborne microorganisms in the built environment
Sources of microbial bioaerosols in the built environment may include humans; pets; plants; plumbing systems; heating, ventilation, and air-conditioning systems; mold; resuspension of settled dust; and outdoor air. The green and red dots represent microorganisms that may be beneficial or detrimental to human health, respectively. Artwork by Tim Skiles