Final answer:
The route of entry for breathing in hazardous substances such as vapors, gases, and dusts is inhalation, which is a significant concern in occupational health and for the transmission of airborne diseases.
Step-by-step explanation:
The route of entry that involves breathing in hazardous vapors, smoke, gases, fumes, liquid aerosols, and suspended dusts is inhalation. Inhalation exposure occurs when these hazardous substances are present in the environment and enter the body through the respiratory system. This type of exposure is particularly concerning in occupational settings where workers may be exposed to such dangers regularly without proper ventilation or protective equipment.
Examples of inhalation exposure include greenhouse spraying operations, work in tractor cabs during pesticide application, and emergency response situations. Airborne transmission of diseases, such as the flu and the common cold, also occurs through inhalation, illustrating the importance of this route of entry for both chemical and biological hazards.