There are four main types of air pollution sources: mobile sources â such as cars, buses, planes, trucks, and trains stationary sources â such as power plants, oil refineries, industrial facilities, and factories
Incubation Period: Average 9-10 days. Period of Communicability: Highly communicable in the early phase and at the beginning of the paroxysmal cough stage (first 2 weeks). The child is no longer contagious after 5 days of treatment.
Measles is a serious and extremely contagious disease. It is caused by a virus that spreads easily through the air, in which it can survive for several hours. Simply by sharing space with a contagious person, even for a short time, an individual can contract the infection and develop the disease.he incubation period (period between the time when a person is exposed to someone who is sick and when he or she develops symptoms) is about 7 to 14 days. An individual is contagious for 4 days before symptoms appear until 4 days after the rash develops.