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.
A person is not contagious during the measles incubation period. A person is mildly contagious when he or she first experiences symptoms, and is most contagious about four days before the onset of the measles rash.Some risk of measles transmission lasts until about four days after the rash starts. Measles Disease. person is mildly contagious when he or she first experiences symptoms, and is most contagious about four days before the onset of the measles rash. Some risk of measles transmission lasts until about four days after the rash starts. Measles Disease.