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.
During the primary stage, a sore (chancre) that is usually painless develops at the site where the bacteria entered the body. This commonly occurs within 3 weeks of exposure but can range from 10 to 90 days. A person is highly contagious during the primary stage. 1  In men, a chancre often appears in the genital area, usually (but not always) on the penis. 2  In women, chancres can develop on the outer genitals or on the inner part of the vagina.  Swelling of the lymph nodes may occur near the area of the chancre.