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.
1 an early sign of a developing condition or disease. 2 the earliest phase of a developing condition or disease. Many infectious diseases such as chickenpox or measles are most contagious during the prodromal period. prodromal, adj.