Formation and penetration of bioaerosol in ventilation systems in buildings of public use

Aim of project
The aim of the research is to study the process of growth of microorganisms, and especially microscopic fungi, inside air conditioning units and in ventilation ducts in buildings of public use (high office buildings, hospitals). Ventilation ducts are contaminated when without adequate and frequent maintenance. Inside them there are conditions which are suitable for growth of various microorganisms. A negative result of such a process is an increase of concentration of bioaerosols and mycotoxines in ingoing air and formation of environment conditions called Sick Building Syndrome. Ventilation systems in some of the chosen buildings of hospitals and offi ce buildings will be examined in this project. The research will comprise measurements of concentrations of the general aerosol and bioaerosol fraction in various points of the system. Samples of filters used in air conditioning units will be examined together with samples of particular deposits from the inside of the ducts. Some laboratory tests on the growth of microorganisms inside filtering structures under controlled conditions of temperature and air humidity will be conducted. Microorganism colonies would be cultivated on a medium which is porous and poor in nutrients to simulate the conditions present in the ventilation duct. The rate of bioaerosol generation by such cultivated colonies will also be tested. A mathematical model of the process of colonization of the ventilation system by microorganisms will be constructed. The model will enable to predict the dynamics of change of bioaerosol concentration in the air at the end of the ventilation duct. A new technique of protection of fi brous filtering structures and fl at surfaces against colonization and growth of microorganisms will be prepared and followed by a patent application in this field.

Expected results
The level of biological contamination of air in high buildings equipped with ventilation systems and air conditioning units will be examined. The measurement results will help to define the degree of microbiological risk in buildings. New techniques of preparation of fi brous filters and preservation of fl at surfaces against microorganism growth will be proposed. A mathematical model of microorganisms spreading in the ventilation system will be proposed. The model will enable to calculate changes of bioaerosol concentration over the years of use of the ventilation system.