ECA 12: Biological particles in indoor environments.

This report is concerned with the strategy and methodology for investigating four major categories of biological particles in the indoor air of private houses, non-industrial workplaces and public buildings (excluding hospitals). These particles are mites and their faeces; dander from pets and other furred animals; fungi, including moulds and yeasts; and bacteria, including actinomycetes.

Comparison of biocontaminant levels associated with hard vs. carpet floors in nonproblem schools : results of a year long study

The aim of that study was to determine whether there was a quantifiable difference in biocontaminant levels between one school with a carpeted floor and another school with hard surface floor. During one year, air and floor dust samples were collected and analyzed. The results suggest that floor covering is not the major contributor to airborne levels of biocontaminants in nonproblem schools.

Measurement of airborne biocontamination in residential and commercial buildings

This report presents the status of airborne biocontamination measurements in France in residential and commercial buildings.

Research into thermal decomposition of indoor suspended bioparticles.

Airborne fungi in indoor air has the possibility to cause the air pollution problems of the fungally infection syndrome and the allergy syndrome, etc. in residence environments. Because the carcass of airborne fungi becomes and allergen, it is difficult to remove the allergen effectively only by mere sterilisation. In this research, the pyrolysis of fungi was examined by using the heat of the high temperature from the heater used the combustion of natural gas.

The optimisation of UVGI air disinfection in a UK hospital building.

A number of studies have shown that approximately 1 in 10 hospital in-patients will acquire a nosocomial infection (NI) '*).These infections are associated with significant mortality rates, and have a large economic impact on health care systems. A Department of Health (DoH) study estimated that in acute care hospitals in England 950000 lost bed days and financial costs off 111 million (1986 rates) were associated with NI '3).Through the use of ultraviolet germicidal irradiation (UVGI) lamps it ii possible to achieve a high degree of pathogen disinfection.

Reduction of microorganisms by HVAC system filters and analysis of the microorganisms passing through the filters.

k order to determine the amount of micro-organism present before and after the filters ofHVAC systems, 6 systems in 5 buildings were monitored every 2 weeks for one year. Measurementswere taken in triplicate and simultaneously before and after the filters using a sixstage Andersen sampler.

Factors influencing effectiveness of ultraviolet germicidal irradiation for inactivating airborne bacteria: air mixing and ventilation efficiency.

As a result of the recent resurgence in tuberculosis incidence, there has been increased interestin using ultraviolet germicidal irradiation (UVGI) of room air to reduce exposures toinfectious agents. This paper presents results of experimental studies investigating how airmixing and ventilation influences the efficacy of UVGI for inactivating airborne bacteria.Tracer gasSFGand tracer particles generated by nebulization of a- salt solution were injected into a full-scale room. The particles simulate an aerosol carrying an infectious agent generated by persons coughing or sneezing.

Effects of ultraviolet germicidal irradiation of room air on airborne bacteria and mycobacteria.

As a result of the recent resurgence in tuberculosis (TB), there has been renewed interest inengineering controls to reduce the spread of TB and other airborne infectious diseases in highrisk settings. This paper presents the results of experimental studies evaluating the efficacy ofultraviolet germicidal irradiation (UVGI) of room air in reducing the concentration of viableairborne bacteria. Bacterial particles (Bacillus subtilis spores and Mycobacteriumparafortuitum) were continuously generated in a 90m room.

Comparisons of microorganism loading from two air filter materials during the first eight weeks of service life.

As part of an ongoing investigation on service life of air filtration material, a new type of airfiltration material (multi-layered polymer) was compared with a widely used material todetermine growth or survival of micro-organisms after normal dust loading. Blinding wasperformed by the manufacturer supplying the materials as anonymous A and B. Microorganismswere extracted after 2, 4, 6, and 8 weeks by washing (shake out) and plating thesolution onto agar media, incubated and differentiated. Vital fluorescence microscopy wasalso performed. The results showed a significant difference (P