Several indoor air biofilters containing higher plants, mosses and microbes have been incorporated into functional offices, where they are a supplemental means of controlling indoor air quality through the removal of volatile organic compounds. In theory a rich microbial community indoors may in fact lower air quality through the production of microbial agents such as spores or aerial bacteria. Questions have arisen regarding the impact of an indoor air biofilter on ambient spore concentrations including the pathogen Legionella pneumophilia.

In buildings with mechanical ventilation, particles accumulate in the supply air filters. We conducted a field experiment in a school to investigate if such pollutants could affect the health of the pupils. In a school building we changed old and new supply air filters in the air handling units, with a cross over design of the study. Pupils answered a symptom questionnaire, and a subset of pupils was also examined by objective clinical methods.

Maintenance workers expressed concern of a potential health hazard due to a strong odor from used ventilation filters during routine maintenance at a research facility. This prompted a thorough examination of the physical and chemical nature of the filters and collected particulate matter. Light and electron microscopy indicated a predominance of opaque small particles, mostly in the submicrometer range. Many were agglomerations of smaller, roughly spherical subunits, consistent with combustion aerosol.

Indoor air quality differences were investigated among five schools with and five schools without active humidity control systems. The active humidity systems provided approximately 15 cfm/person of ventilation air, while the schools without the active humidity control systems averaged less than five cfm/person. The space humidity levels in varying widely without active humidity control, and rose to unacceptable levels during summer shut-down periods.

Germicidal UV (UVC) lamps have a long history of use for inactivation of microbial aerosols. The majority of the literature has considered control of infectious diseases, such as tuberculosis (TB) in medical facilities. Emphasis has recently been on ventilation duct use of UVC. Under these conditions, infections agents are usually of less concern than environmental organisms. Much less information is available regarding common environmental organisms. The present work reports the ability of UVC lamps to inactivate 7 representative microbial aerosols in ventilation duct conditions.

Published guidelines on mold remediation do not specify sampling protocols to measure the efficacy of remediation efforts. The purpose of this study was to evaluate fungal remediation of contaminated ducts by comparing the amount of residual surface contamination to the amount in new ducts. Fungal contamination of galvanized metal and rigid fibrous glass ducts were evaluated using fluorometric and microscopic methods. Fungal contamination was measured in newly installed ducts in addition to pre- and post-remediation. Newly installed ducts had low levels of fungal debris.

Most single-family homes in America today are designed with a single-zone climate control system. This is typically an energy inefficient and ineffective method of conditioning a home. Multi-zone climate control systems are considered to provide improved means of conditioning single-family homes. More so is the case with multi-story homes where thermal balance is difficult to achieve between the lower and upper floors using a single-zone system.

The influence of inhabitants on indoor air quality (IAQ) was studied. The aim of the study was to find out how the inhabitants themselves and their living activities affect the IAQ. The concentration of volatile organic compounds (VOCs) and ammonia (NH3) in indoor air was measured in inhabited and in empty dwellings. A air change rates were also defined. Altogether 24 dwellings were examined. The results were compared with the surface floor area of the dwellings, the number of inhabitants, the number of pets and the absence or presence of smoking.

On March the 1st 2000 the Finnish Tobacco Act was amended, and now includes restrictions on smoking in restaurants and bars. Establishments can reserve a maximum of 50% of their service area for smokers, and the spreading of tobacco smoke into non-smoking areas must be prevented. In addition, the working areas at bar counters have to be smoke-free. 16 restaurants and bars participated in the study both before and after the introduction of the Finnish Tobacco Act.

Restaurant workers have a high risk to be exposed to environmental tobacco smoke (ETS) in their work. In Finland the latest tobacco Act has set more stringent requirements for the smoking in restaurants. Despite of the tightened legislation most of the restaurant employees are still continuously exposed to ETS. Ventilation techniques enable significantly to reduce employees exposure to ETS in hospitality facilities, where smoking is permitted.