microbiology

In this study, serial environmental measurements in 12 large buildings in Taiwan have been made to control the air exchange efficiency on the indoor microbial contamination. High levels of airborne microbes seem to be more easily observed in buildings equipped with fan coil unit system than with air handling unit system.
Adequate filtration of fresh air intake should be imperative to control effectively microbial contaminations of outdoor origin.

Ultraviolet germicidal irradiation (UVGI) systems are used to disinfect air, they consist in mounting shielded UVGI lamps at high level in an upper room zone, and the natural convection currents that occur in a room space carry airborne microorganisms through the UV field. This study demonstrates that the effectiveness of those systems is dependant on both the ventilation regime and the in-room air mixing.

An investigation method based on the HACCP system was applied to eleven representativeoffice buildings with HVAC system located in different latitudes in Italy, to evaluate themicrobiological quality of the air supplied. Bacterial and fungal levels near supply airdiffusers pointed out medium-low contamination and analysis of data showed a highermicrobial load in the buildings located in the South of Italy with respect to those in the North.IAQ of five buildings was examined in more detail. Air samples demonstrated an overallgood microbial removal efficiency of the examined HVAC system.

Microbial sampling was used to study indoor air quality in a building where the employees had complained about IAQ for many years. In addition, the symptoms and complaints of the employees working in the building were surveyed by MM40-questionnaire. Workers complained about dust, dirt, dry, stuffy air and unpleasant odor. Tiredness and irritation of upper respiratory tracts and eyes were the most common symptoms. IgG antibodies against microbes commonly found in water damaged buildings, were determined from the serum samples of the employees.

The survey concerned three swimming pools using a similar type of basic water treatment, buthaving different structures and ventilation systems. The survey included measuring air currentvelocities above the pools and studying the microbiological and physico-chemical quality ofthe pool water. In addition, microbes were determined from the indoor air, structures andventilation systems, and airborne particles and volatile organic compounds from the indoor airsamples. The total particle concentration of the indoor air and their size distribution variedbetween the swimming pools.

Many studies have shown that ventilation systems often host bacteria and fungi that may bedangerous for the health of people exposed to them. This problem may be particularly acute inhospitals, where exposed people are more sensitive. The paper presents the methodologydeveloped to study the effectiveness of some plants extract, the essential oils to hindermicrobial growth, in order to propose an indoor air purification method based on thegermicidal and odorant properties of the essential oils. First results are encouraging.

The use of high-speed rotary and spray-producing instruments can pose a serious risk indental clinics, by continuously creating a potential harmful contamination of the room. Indoorclimate parameters (temperature, relative humidity) and microbiological airbornecontamination (total bacterial count at 37C, fungal particles) were evaluated in 12 privatedental clinics, partially equipped with air conditioning systems. Carbon dioxide airconcentrations were also measured to evaluate the efficacy of air exchange. Air microbialcounts were highest in the consulting rooms and waiting rooms.

The aim of the investigation was to evaluate different methods to sample microbial cell wallagents (MCWA) indoors and to relate the results to clinical markers of inflammation amongpersons (n = 27), living in houses with suspected mould problems. Airborne particles weresampled for 8 h or by agitating floor dust. Sedimented particles were collected from floor dust.Analysis was done for endotoxin and (1?3)--D-glucan. Endotoxin was found only in a few ofthe agitated floor dust samples.

Research has suggested associations between indoor microbial exposures and respiratorydiseases across the globe. This aim of this study was to examine whether microbe levels wereassociated with housing characteristics. Study homes were selected from a prior citywidesurvey, and housing characteristic questionnaires were distributed afterwards. Airborne fungi,bacteria and dust samples were collected. Samplings were conducted every month for a year.Having pets at homes and age of the house were found to affect the indoor concentrations ofDer p 1 and Der p 2.

This presentation will review two major microbial cell wall agents (MCWA) - endotoxin and (1->3)-ß-D-glucan - concerning their toxic effects after inhalation and their role for the development of symptoms among persons in buildings with humidity problem.