[MUSIC] Hello everyone. In this video, we will introduce bioaerosols. Bioaerosols are one type of particulate matter. They are airborne particles, large molecules or volatile compounds that are living, containing whole or parts of biological materials. Composition of the bioaerosol particles in a place varies with sources and environmental conditions. Their sizes vary from less than 1 micron up to 100 microns. Common bioaerosol particles found in indoor air are bacteria, fungi, and viruses. Bacteria are single-celled structures and have no membrane to separate the nucleus material from other cell components. Bacteria range in size from about 0.5 microns to 5 microns. Bacteria usually form colonies that are composed of millions of single cells and large enough to be visible. You find bacteria everywhere, particularly in dusty, dirty places inhabited by humans or animals. Some bacteria are harmful, while some are beneficial to humans. Mycobacterium tuberculosis, MTB, is a type of bacteria that can cause disease. It is the causative agent of tuberculosis - TB. TB is one of the greatest modern health since it is highly contagious. Single bacilli is capable of causing an infection in laboratory animals. In an indoor environment, fungi refer to the group of microorganisms whose cells have a membrane separating the nuclear material from the rest of the cell protoplasm. Fungi reproduce sexually and asexually, often with an abundance of spores, or seeds, which can be carried in airstreams. Fungi are ubiquitous in nature and inevitably enter buildings from the outdoors to set up colonies wherever the conditions for growth are favorable. Fungi need external organic food sources and water to survive. They are very difficult to eradicate completely once established in a building. There are various groups of fungi such as yeasts, rusts, mold, mildews, and smuts. Alternaria is an example of fungi. Alternaria does not cause any disease, but can cause considerable distress to allergic patients. It is known as a fungal allergen and is associated with Sick building syndrome. Cladosporium is another example of fungi. It is also a common indoor air contaminant. You can find cladosporium on living and dead plant materials and wet building materials. It does not cause disease normally, but is associated with Sick building syndrome. Viruses are the smallest among the microbe group. Their size, shape, content, and activity vary significantly. The size of a virus ranges from 0.02 micron to 0.3 micron. Unlike other living cells, viruses do not contain enzymes that can transform complex compounds to simpler substances for nutrition. Therefore, viruses must rely on a host cell to live and reproduce. Some viruses are transmitted from person to person by droplets in the air. Orthomyxoviridae is an influenza virus that is highly contagious. Influenza virus is transmitted from person to person, mainly in droplets released by sneezing and coughing. Influenza is a febrile disease of the respiratory tract and periodically sweeps the world, sometimes causing tens of thousands, and sometimes millions, of deaths. Variola is a virus that can cause smallpox. It is transmitted by direct contact, and some evidence show, it can also be transmitted by airborne routes. Variola is a pathogen that can lead to death, but thanks to global vaccination, it has been eradicated. To conclude, in this video, we introduced what bioaerosols are and different types of bioaerosols, bacteria, fungi, and viruses, and their examples.
