The Environmental Protection Department conducted a territory-wide indoor air qualitysurvey in Hong Kong. The report released in 1997 confirmed that one-third of the sampledbuildings were classified as sick buildings. Many of the causes could be attributed tounacceptable indoor air quality (IAQ). In response to this, the Indoor Air Quality ManagementGroup distributed a Guidance Notes for the Management of Indoor Air Quality in Offices andPublic Places for public consultation. It includes an annual IAQ certification scheme.
The aim of the study was to investigate the effects of elevated summer indoor temperatures onperceived comfort, symptoms and subjectively assessed productivity in an office building.The measurements during spring 2002 showed that indoor environment was at the normalFinnish office building level. The mean room temperature during the 2-week measurementperiod was 22C. An indoor air questionnaire (MM-40-FIN) including additional questionsabout work efficiency was presented to the employees during the measurements. Theperceived indoor environment was at the normal Finnish office level.
A method has been developed to investigate the comfort in office buildings. It is based onboth measurements and a questionnaire. The measurement apparatus, the so-calledAmbiometer, can record both the main comfort parameters, such as temperature, humidity,noise, light and odours, and the occupant's perceived comfort. Information regarding theindoor climate and the working environment is noted on the questionnaire.Experiments were conducted on about 50 offices in France.
Ozone concentrations were monitored up- and downstream of used filter samples at airflowsof 1.0 and 0.2 l s-1. The ozone concentration in the air upstream of the filters was ~75 ppb,while the concentration downstream of the filter was initially ~35% lower at 1 l s-1 and ~55%lower at 0.2 l s- 1. Within an hour the removal efficiency had decreased to roughly 5% at1 l s- 1 and 10% at 0.2 l s- 1. These filter samples were then placed in either nitrogen or ambientair for 48 h. Afterwards it was found that there was partial regeneration of the filters ozoneremoval capabilities.
Velocity measurements were performed in the air flow resulting from two horizontal opposite air jets along a ceiling. Results show how the air velocity decreases along each of the two air jets, compared to the velocity decrease along a single free air jet.Experimental results are compared with a correlation from the literature. The agreement is good.
An advanced supply air filtration unit has been developed, and its performance was evaluatedin the laboratory. The filter consists of an electrically enhanced particle filter and an adsorbentfilter for gases. It has been designed for installation near supply air outlets. The performanceof the filtration unit was measured in the laboratory. The results showed that the filtrationefficiency for submicron particles was over 95% during the whole lifetime of the filter. Theremoval efficiency of the gas filter for toluene was also high, over 95%.
Tracer gases are often used to assess airflow rates in air handling units. Published methods aremostly designed for units with recirculation ratios lower than those commonly found inSingapore and other tropical countries. Large recirculation ratio homogenize theconcentrations, so that concentrations in supply and extract ducts are close to each other. Inaddition, such units often present a large time constant, so the time needed to reachequilibrium is very large. A procedure for tracer gas dilution technique adapted to such airhandlingunits is presented.
School indoor air quality has become of concern recently in Korea. In this paper, it is intendedto investigate the ventilation performance and thermal comfort characteristics of a classroom,when an outdoor air system is installed in addition to a ceiling-mounted heat pump system.Experiments were conducted in a full-scale model classroom to collect experimental data tovalidate numerical schemes. Three-dimensional temperature distributions were measured withthermocouples distributed throughout the space, and ventilation effectiveness was measuredusing a tracer gas technique.
Tracer gas sorption in and permeation through building materials influence tracer gas ventilationmeasurements. Therefore, it is important to have knowledge about these processes.The permeation of three commonly used tracers (SF6, N2O and the PFT C6F6) through untreatedgypsum board has been experimentally investigated. The result shows that all three tracers diffusereadily through this material (diffusion coefficients in the order of 1 10.-6 m2/s). Caution shouldtherefore be exercised when using tracer gas measurements in rooms with walls of gypsum boardor other porous materials.
Ventilation is the most effective procedure to reduce indoor air pollutant. Volatile organiccompounds (VOCs), which cause health related symptoms, are often detected in the indoorenvironment. The way of ventilation should be decided depending on the level of VOCs. Thelevel of VOCs and ventilation rate are usually measured individually. This study will proposea simple method to measure both the ventilation rate, by perfluorocarbon tracer gas technique(PFT), and VOCs concentration immediately by using a single sampler.
Login