THE great danger in not opening the windows of the bus is the greater possibilities of contracting airborne diseases such as tuberculosis, flu and colds since you would be breathing in the air the other man lets out. More obviously, when a person with flu sneezes, tiny droplets are dispersed from the nose and mouth spreading disease all over the bus.
If the windows are open, the air comes in and out and circulates and passengers have some protection from airborne diseases.
Teachers should teach this lesson to their health science classes. Bus conductors could help by always keeping the windows open.