Microbes can be aerosolized through both natural and human activities. Human 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 bacteria which can result in life-threatening infections. With as much as 80% of our time spent indoors.air quality in these environments can also result in sick building syndrome and asthma attacks.