It was observed that aerosols spread from the front of the classroom were able to reach the back of the room within 10-15 minutes of transmission. However, because of the active ventilation present in the environment, the transmission was 1/10th that of the source. The highest risk of catching COVID-19, in a closed environment, is for those who are sitting within the close vicinity of an infected person, and transmission risk may cut down for those sitting far off, provided good ventilation is present.
However, it should be noted that the model only applies in a limited setting. If the exposure to an infected carrier increases, so does the infection risk, regardless of good ventilation.
Aerosol transmission, can perhaps, be the biggest transmitter for infections in the current scenario, as more and more schools, institutions, malls and public places throng open. Not only are aerosols suspended when a person expels out droplets in the air, but it can also linger when somebody breathes sings or talks.