Classrooms in New Zealand schools are mostly low rise buildings with natural ventilationdesigns, sized for summer cooling. This study has investigated winter ventilationperformance in twenty-four classrooms in twelve primary schools in the Wellington region.Its purpose has been to provide baseline data on the effectiveness of existing naturalventilation, along with approximate pollutant profiles on which to base new mixed modeventilation designs.

The need to separate impurities from air or other gases has increased as regards both the degree of separation and the necessity to separate finer particles. An 85% efficiency filter is a prerequisite for the correct functioning of ventilation systems and to improve indoor air quality (IAQ).

A test room was used to evaluate the impact of airflow parameters on the effectiveness of an air cleaning system. The room’s dimensions were nominally 11.2 m x 5.7 m x 2.7 m. The room has a drop-ceiling with space above for installation of above-ceiling air cleaning equipment and routing of ventilation ductwork. The HV AC system supplying the room could be turned on for constant flow (-349 ls·1) or left off to independently evaluate the effectiveness of the air filtration system.

A test rig for long-term tests of activated carbon filters was developed consisting of eight parallel test-filter sections. The test-rig was installed on the roof of a six storey commercial building located in the centre of Goteborg, Sweden. By this arrangement, eight activated carbon filters are tested simultaneously under realistic conditions, using the pollutants in the ambient outdoor air as challenge substances.

Ventilation filters composed of electrostatically-charged fibers, also referred to as electret filters,are know to have the potential to decrease in filtration efficiency with use. However, little datahave been available on whether such decreases are seen in actual applications.

Forced air furnaces are a common Canadian heating system. Traditionally, filters placed in thecirculating air ductwork were designed to protect the furnace and fans. Over the last severalyears, there has been increased emphasis on improving the filtration efficiency with the goal ofreducing occupant exposure to respirable particulate. The current research project rotatedseveral filters through six houses in southern Ontario during the heating season.

The cabin air filter performance is of prime importance for the air quality in vehicles. New clean filters were tested but also filters loaded with actual traffic contaminants. Both laboratory and field measurements were included in the study. Direct reading instruments and filter sampling was used for the loading rate determinations. The filter performance includes particle filtration efficiency with regards to particle size, filter loading and flow rate as well as filter pressure drop related to filter loading. Test results for these paramenters are presented.

It is recommended to keep the ventilation filters dry. However there are manyventilating systems that cannot fulfil this requirement all the time. It is then interestingto know the state of filters in use, and how they perform during extreme wetconditions, especially at the end of their lifetime.This investigation includes used filters collected at the time of normal change offilters.The used filters absorbed a different amount of humidity. The particle filtrationefficiency was nearly the same as for unused filters (comparing only filter classF7/EU7).

This paper presents ozone removal efficiencies, measured over an extended period of time, inthree different settings: a test plenum, an air handler providing outdoor air to a Class 100cleanroom, and a plenum downstream of an air handler providing outside air to a second, smallerClass 100 cleanroom. In each of these settings, the initial ozone-removal efficiencies werecomparable. After 8 years of service, the charcoal filters servicing the first cleanroom wereremoving about 60% of the ozone in the airstream.

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.