Here we look into the spread of aerosols indoors that may potentially carry viruses. Many viruses, including the novel Covid-19, are known to spread via airborne and air-dust pathways. From the literature data and our own research on the propagation of fine aerosols, we simulate herein the carryover of viral aerosols in indoor air. We demonstrate that a great deal of fine droplets released from an infected person coughing, sneezing or talking propagate very fast and to large distances indoors, as well as bend around obstacles, lift up and down over staircases, and so on. This study suggests equations to evaluate the concentration of those droplets, depending on time and distance from the source of infection. Estimates are given for the safe distance to the source of infection, and available methods for neutralizing viral aerosols indoors are considered.