This paper provides a theoretical error analysis of common airflow measurement and control techniques to maintain minimum outside air intake rates in variable air volume (VA V) systems. The results of the error analysis indicate that control strategies using direct airflow measurement from either an averaging Pitot-tube array or an electronic thermal anemometry provided the best ventilation control.

Recent concerns have been expressed with regard to emissions of glass fibers from heating, ventilation, and air conditioning (HV AC) systems. In this literature review, over 350 citations were found, of which 10 reported original measurements of glass fiber concentrations associated with the presence of fibrous glass duct lining or duct board, and two yielded sufficient data from which emission rates could be calculated.

Ventilation systems may in some cases be a major contributor to indoor air pollution. Several studies have shown that the pollution mainly originates from the filters. Microbial growth in the filters is seen as a cause for this pollution. The sensory pollution from a standard glass fiber filter and a glass fiber filter treated to inhibit microbial growth (both EU7) were compared. No clear pattern was found in the influence of the filters on the sensory air quality. The differences between the two tested filters were not significant.

Concerning artificial ventilation of interiors, microbial processes on air filters are assumed to cause pollution of the supply air with possible damage to the exposed persons' health. Therefore, the reaction of microorganisms on air filters was analysed in this project. The analysis focused on the influence of air temperature, relative air humidity, the filter medium and service life as determinants for microbial growth on air filters. The experiments showed that the parameters air temperature, filter medium and service life had no significant influence on microbial growth.

For many years there has been an increasing rate of complaints on the air quality in nonindustrial buildings. The occupants suffer from many diseases especially problems of breathing. Besides other reasons the air-conditioning systems themselves pollute the indoor air because dust, aerosols and other substances deposit inside the system. Therefore an airconditioning system, which has been operating 26 years was investigated. The aim was to find the main pollution sources of the system and possibilities to eliminate them.

Field studies were carried out on air contamination by dust particles from air conditioning systems in four buildings in Tokyo area. We tried to investigate contamination of airborne particle and surface contamination by sedimentary dust in air duct, and considered a matter in all its aspects that caused indoor air pollution.

1. Time variations of airborne particle concentrations at supply outlet were influenced by the operation of air conditioning system.

A nine-home field study was conducted to investigate the impact of mechanical air duct cleaning (ADC) methods on indoor air quality (IAQ) and system performance. ADC services were provided by the National Air Duct Cleaners Association (NADCA). Only mechanical ADC methods were evaluated. Surface treatments, such as biocides or encapsulants, were not part of the study. Pre- and post-ADC measurements were used to evaluate impacts.