Construction in healthcare facilities is a major risk for airborne agents infecting immune compromised patients. Standard air quality analysis has included air sampling for airborne fungi. These culture data require weeks for transport, incubation and identification. During a demolition and construction of a new medical facility an infection control risk assessment(ICRA) determined pre-construction precautions and surveillance methods. The surveillance utilized real time air particle analysis and culture methods to determine relevant indicators of potential hazards.

Several studies have shown that supply air filters in office buildings, schools etc. occasionally get wet due to weather impacts. The aim of this study was to investigate whether performance characteristics, such as pressure drop across the filter and filtration efficiency, change when two different kinds of air filters become soaked and dried. The filters used, were a fiberglass bag filter and a plastic fiber bag filter, each of filter class F7. The study showed that the filter getting wet did not affect the shape of the dried filter material of plastic fibers.

Several studies based on analytical models and numerical simulations have shown that it is difficult to control airborne particle movements in a ventilated room. However, more knowledge and information on particle characteristics and particle movements, in combination with new numerical simulation tools, have recently made it easier to estimate particle patterns. In the present paper new information is used to evaluate the role of filtration and ventilation in the particle elimination process.

Calculations using CFD are presented for adventitious openings in which the flow is not fully developed. It is shown that the quadratic equation performs significantly better than the power law i.e. a recent claim that the power law equation is preferable to the quadratic equation under such circumstances is not supported. Other recent claims that have been made to support the power law in preference to the quadratic are also examined and reasons are given as to why they are unfounded for conditions of typical, naturally driven air infiltration.

Indoor air cleaners are available on the market but a lot of them are not tested and their performances are not known. The main objective of our study was to develop a laboratory test method which allows to determine the life span of indoor air cleaners. Loading of the device is carried out with tobacco smoke which is an air pollutant that reflects real conditions. Fractional efficiency and air flow rate of the device are measured at the initial stage (clean device) and step by step as the device becomes loaded.

The National Institute for Occupational Safety and Health (NIOSH) has undertaken a long-term performance test of heating, ventilation, and air-conditioning (HVAC) system filters. This testing is being conducted at the NIOSH facility in Morgantown, WV in an air handling unit (AHU) that services the animal quarters. The six-pocket bag filters in this AHU have been replaced with higher efficiency mini-pleat V-Bank filters and have been monitored monthly for filtration efficiency.

Air quality begins with good engineering air handling system (HVAC) controls. Air handler filters should remove the major particulate matter from incoming ambient air. A study of various NIOSH air handler bag filters was conducted to determine their filter efficiency against submicrometer particles (0.03-0.4 micrometers), since submicrometer particles are the most penetrating. Aerosol penetration measurements show an extremely large range of filter efficiency.

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.