Occupational Safety and Health Administration. 1  Department of Labor, Labor Department, DoL, Labor - the federal department responsible for promoting the working conditions of wage earners in the United States; created in 1913.
The oxygen and carbon dioxide exchange take place in the alveoli. Primary bronchi are located on the upper portion of the lungs, secondary bronchi is located at the center of the lungs and tertiary bronchi is located near bottom of the organs above the bronchioles.
The bronchi are two tubes that branch off the trachea, or windpipe. The bronchi carry air to your lungs. The most common problem with the bronchi is bronchitis, an inflammation of the tubes. Bronchitis can be acute or chronic.