Microbes can be aerosolized through both natural and human activities. Humans influence the transport of aerosolized microbes through a variety of activities including,for example, land application of wastes, The introduction of cooling towers and hot showers also creates a route for human exposure to aerosolized Legionella bacterria which can result in life-threatening infections. With as much as 80% of ous time now spent indoors, air quality in there environmenta can also result in "sick building syndrome" and asthma attacks. Microbial derived allergens are also readily transported into and through the air. Mycotoxins produced by soli fungal molds including Aspergillus, altemaria, Fusarium and Pennicilliam can cause a variety of health problems. For example aflatoxin produced by Aspergillus Flavus is a potent carcinogen.