Question

why are overcrowded and poorly ventilated areas a major factor in the spread of air borne diseases

Answer 1

because over crowded areas have more population and due to this pollution is caused and in These areas no facilities are there that's why there are major factors of spread of airborne disease are there

Answer 2

overcrowded and poorly ventilated areas a major factor in the spread of air borne diseases because of the following reasons-

1. when an infected person coughs or sneezes, the droplets get mixed with the air.
2. when the droplets enters into a healthy person when he breathes he get infected.
3. now ,if the ventilation is poor , fresh air could not enter and the bad air could not escape.
4. as a result the mixed air with infected droplets continue to circulate in that room resulting in spread of air borne disease.