dust

INTRODUCTION: The Finnish Society of Indoor Air Quality and Climate (FiSIAQ) introduced over twenty years ago in 1995 a Classification of Indoor Climate, Construction Cleanliness, and Finishing Materials and the third edition will be published autumn in the year 2017. Based on the criteria set in the classifications, The Building Information Foundation RTS sr started the M1-labelling of air handling components in 1999. Name of the classification is Cleanliness Classification of Air Handling Components.

This paper reviews the literature for evidence of links between ventilation rates in dwellings and moisture related respiratory health with a particular focus on house dust mites (HDM) and fungal growth. There is general consensus that a link exists between ventilation rates in dwellings and respiratory hazards (for example HDM). There is also general consensus of a link between these respiratory hazards and respiratory problems, but it is not clear to what extent hazards cause ill-health.

This thesis is based on studies undertaken during the period 1998-2003 at the HVAC laboratory of Helsinki University of Technology.The thesis focuses on dust accumulation in, and removal from, recently installed supply air ducts and on the bristle behaviour of rotating duct cleaning brushes. The results of dust accumulation, measured using three different methods, were compared and the amount of dust in newly installed air ducts was evaluated. The vacuum tests was found to be an efficient method of collecting dust samples on the duct surface.

For that study, 24 healthy non-sensitive persons were tested to analyse the respiratory effects caused by exposures to office dust. The results of the study suggest that most of the tradiitional risk factors can be rejected as single responsible risk factor.

A simple model of a rotating duct cleaning brush was presented using large deformation elastic theory. The results obtained by the model were compared with the results obtained by a laboratory test. Especially, the effect of air drag on the brush behaviour was considered.

Rotating brushes are commonly used in cleaning air ducts. A very simple model simulating the behaviour of a typical brush bristle is presented. The model consists, in effect, of a combination of a polynomial trial solution, the point collocation method, Simpson's integration rule and a Mathcad code. The main interest from the cleaning point of view is in determining the contact force and the contact angle between the bristle tup and the duct surface. The effect of the degree n of the polynomial trial solution - n=4, n=6, n=8 - is studied.

The bristle of a rotating cleaning brush for air ducts was modelled using large deformaion elastic theory. The point collocation method with a trial solution consisting of undertermined parameters was employed to discretize the resulting non-linear problem. The main interest was in determining the value of the bristle tip contact normal force N, the bristle tip contact angle B and the torque T needed to rotate a brush. The results obtained using the simple model were compared with the results obtained from a laboratory test.

Electrostatic air cleaners (precipitators) were tested in four classrooms during ordinarylessons for four weeks. Airborne dust in the classrooms was collected on filters using two different kinds of samplers: IOM-sampler and a new kind of ionizing sampler. The amount of collected dust was evaluated by visual inspection (filter blackening) and the content of cat allergen was measured using an amplified ELISA assay. It was found that the filter blackening was 64% lower when the air cleaners were active than when they where inactive (p

The paper reviews the effect of environmental parameters on the migration of particulate matter. Themethodology involves simultaneous monitoring of particulate matter using dust monitor at indoor and outdoor locations along with the ambient environmental conditions. The study is of great significance as Particulate Matter (PM) has been reviewed in terms of particle count, which is more significant as compared to particle mass. In this paper, the variation of Indoor (PM) /Outdoor (PM) calculated on the basis of count are studied as a function of ambient wind speed, temperature and humidity.

The aim of that study was to test the impact of cleaning on indoor environement quality. Surface dust measurements were made on samples taken from office rooms before and after cleaning during the heating period of the buildings. Before the sampling, the occupants completed a questionnaire survey. The data were analyzed then discussed.