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 cold is an upper respiratory infection characterized by a combination of coughing, sneezing, congestion, runny nose, headache, and/or sore throat. It is caused by one of a multitude of viruses and is very contagious. The period of contagiousness actually starts a day or two before you even feel sick. The most contagious period is when the virus first enters into your body and starts to make copies of itself. This is because your immune system has not yet had time to fight back. This period of maximum contagiousness lasts about 3 to 4 days and is when you are suffering the most. After this time your immune system starts to fight back and the viral level slowly drops and you become less and less contagious.