Influence Of Airflow Pattern On Indoor Microbe Contaminants Dispersion

In modern daily life, people spend nearly 80-90% of all time in indoor environment, so their health directly relate with the indoor air quality. Among the research on indoor air quality, the issue of indoor microbe contamination has received widely and highly respect of scholars both home and abroad. The outbreak of Severe Acute Respiratory Syndrome (SARS) and the spread of Bird Flu (H5N1) and Swine Influenza (H1N1) raise people's attention on microbe contamination to an unprecedented level. Numerous data and results of research show that the bio-particles with virus can spread through air, which make people that staying in indoor environment more likely to contact and be infected by virus. Airflow pattern exerts a vital influence on indoor air quality. To find an effective way from the perspective of air distribution and flow pattern to quickly remove and control the bio-particles is the chief task on inhibiting the indoor microbe contamination by HVAC equipments.The issue of indoor microbe contamination was initiated by theoretical calculation. Basing on the aerosol dispersion model and microbe characteristics, force analysis on the threatening bio-aerosols of 1~2μm was conducted in order to investigate their airflow following performance. According to the results, bio-aerosols of this particle size have good airflow following performance.This article put forward the even distributed concentration predicting model and the uneven distributed concentration predicting model aiming at describing indoor bio-aerosol dispersion. They were validated and further modified respectively according to the experiment and would have good predicting effect on evaluating and defending the dispersion of indoor microbe contamination.During the experiment test, up air supply, lateral air supply and under floor air supply combined with three types of air diffuser for common office environment were tested for their wind speed field in a full size chamber. Uneven Coefficient and ADPI were used to evaluate the evenness of these three air flow pattern, while Self-cleaning Time and Air Exchange Efficiency were used to appraise their ability of pollutant removing. Bacteria emanating experiment was conducted simulating the situation that a pathogen carrier generates bio-aerosols by breathing with slight cough. With reasonable emanating system and air sampling method, two bio-safety indexes were established to appraise the effect of bacteria source on other position under different airflow pattern. As results of comprehensive comparison, under floor air supply could have better effect of preventing infections in indoor environment and the airflow pattern formed by different air diffuser affects the airflow distribution.Additionally, settling microbe was found to be related with air turbulence to a certain extent. The preliminary exploration embraces the reference value for further research on this subject.