AIVC - Air Infiltration and Ventilation Centre

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Odor intensity of a real room field evaluation and laboratory investigations

A simple method was used to assess odor intensity in indoor environments by a trained panel. Reliable results were obtained. Other factors, i.e., interaction with other senses, annoyance and other cognitive processes seemed to influence individual evaluation, especially during adaptation. Therefore, laboratory experiments could be useful to assess immediate odor intensity with minimum context influences. Comparison of odor sampled in Tedlar bags and in the living room were acceptable in terms of intensity but not in terms of recognition and description, indicating presence of biases.

Labeling system for clean ventilation components

Labelling of HVAC systems is a direct consequence of the publication of test procedures and recommended criteria in Finland. Cleanliness parameters are dust quantity, oil residues and odours emissions. Discussion isf continuing on filters classification including their efficiency (EN 779) but also odour emissions.

VOC emissions from dusty air filters

The study examined emissions from dust collected on 2 stages ventilation filters in winter in Helsinki or in its outskirts. The filters contained a lot of fresh particles due to traffic, combustion, and power production. The carbon content was highest in the dust, which was collected from a pre-filter. In previous studies, the intensity of odors from filters was found to be strongest in the winter.

Indoor air quality assessment based on human olfactory sensation.

Investigates IAQ by making subjective assessments of perceived air pollution caused by human bioeffluents. A panel comprising 107 people reported on odour intensities and acceptability of bioeffluents from 54 other people as occupants. Twenty per cent of the judges described dissatisfaction caused by bioeffluents at 1.5 on the Yaglou's odour intensity scale. To satisfy 80% of the judges entering the chamber, a ventilation rate of around 7 litres per second per person was necessary.

Ventilation rate as a determinant of symptoms and perceived odours among workers in daycare centres.

Assesses sick building syndrome symptoms and perceived odours for daycare workers, in relation to ventilation rates in Finnish daycare centres. Thirty centres were chosen for the study, which consisted of 268 female nursing workers. The workers completed a questionnaire. Mechanical supply and exhaust ventilation systems constituted most of the centres' systems with 37% having mechanical exhaust alone. The authors noted a very varied exhaust air flow in the children's rooms, from 0 to 11 L/s per person. Air change rate varied from 0 to 5 m3/hm3.

Ventilation requirements for the control of body odour in spaces occupied by women.

The intensity and acceptability of body odour was assessed 29 times on entering an experimental auditorium occupied by 106 women, by 40 female and 39 male judges. The experiment lasted 3 hours 50 minutes and the ventilation rate was varied while the air temperature was maintained at around 20-21 deg C. CO2 was measured throughout. It was found that there were no substantial differences in the ventilation rates required in rooms occupied by men and women. In order to satisfy 80% of people entering a space, a steady-state ventilation rate of about 8 L/sec person is necessary.

The effect of ventilation and air pollution on perceived indoor air quality in five town halls.

This study was based on measuring the physical and chemical characteristics of indoor climate variables in four town halls in Copenhagen in Denmark and on the odour-intensity judgements by a panel. Three of the buildings had high levels of work-related mucosal irritation and work-related general symptoms; the other one did not. There was a significant correlation between the total concentration of volatile organic compounds (TVOC), the air temperature and the panel's ratings of odour intensity and acceptability in the rooms.

Chemical and sensory emissions from HVAC components and ducts.

Used a trained sensory panel and chemical and microbial measurements to examine the odour generation of the various components of air handling units. States that the results revealed that the supply air perceived air quality can be affected by the system. Nearly all the components of the system were sources of pollution, with used fibre filters the worst, although there were significant differences between the different components. Oily, dusty and dirty surfaces were the worst sources. Increasing the airflow did not improve the perceived air quality downstream of the components.

Fungal production of volatiles during growth on fiberglass.

In a laboratory chamber experiment, acoustic and thermal fibreglass insulation materials used in HVAC systems were colonized with fungi, which produced odour-giving volatiles. Suggests that these volatiles may be implicated in experience of indoor air quality and sick building syndrome symptoms.

Tar fumes trigger inquiry that finds source of IAQ ills at school.

Describes a case of an elementary school which suffers indoor air quality problems as a result of the application of hot coal-tar to the roof, causing major health concerns. Eight roof-mounted air handling units provided heating, ventilation and air conditioning. The space above the ceiling served as the return-air plenum. Four AHUs provided ventilation to most classrooms with variable air volume boxes controlling airflow. Outdoor air intake dampers on each AHU supplied 10% outdoor air to each wing of the school.