Final answer:
The statement is true; airborne organisms that can cause lethal infections, such as those handled in BSL-3 and BSL-4 laboratories, require significant safety measures to mitigate the risks associated with their study or manipulation.
Step-by-step explanation:
The statement that organisms transmitted through aerosols belong to biosafety level 3 and above is True. BSL-3 agents include pathogens such as Mycobacterium tuberculosis, Bacillus anthracis, West Nile virus, and the human immunodeficiency virus (HIV), which can potentially cause lethal infections via inhalation. Laboratories handling these organisms require numerous safety precautions, including restricted access, protective equipment, and specific facility design to control airflow and prevent contamination.
Moreover, BSL-4 agents represent an even higher level of risk. These include the Ebola and Marburg viruses, which are highly contagious, often fatal, and for which there are no reliable treatments or vaccines available. BSL-4 labs involve even more stringent safety measures than BSL-3 labs, such as mandatory full-body protective suits or working within biological safety cabinets, along with specialized facility and air handling requirements.