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EXPERIMENTAL STUDIES ON AEROSOL TRANSPORT PROCESSES IN DWELLINGS USING INACTIVE TRACER TECHNIQUES

Objective

THERE IS A NEED FOR DETAILED UNDERSTANDING OF THE INFILTRATION AND TRANSFER PROCESSES WITHIN DWELLINGS, BOTH IN THE CONTEXT OF POST-CHERNOBYL ASSESMENTS OF 'INTEGRAL' DATA AND FOR RISK ASSESSMENT STUDIES. THERE IS A COMPLETE LACK OF RELEVANT DATA BOTH TO SUPPORT NUCLEAR-RELATED STUDIES SUCH A THE CUMBRIAN HOUSEDUST ACTIVITY SURVEY (FOR WHICH IMPERIAL COLLEGE HAVE BEEN THE MAIN CONTRACTOR IN THE U.K. DEPARTMENT OF THE ENVIRONMENT) AND GENERAL STUDIES OF INDOOR AIR POLLUTION. DATA IS REQUIRED ON INFILTRATION, DEPOSITION ON VARIOUS SURFACES, MECHANICAL INGRESS AND TRANSPORT, RESUSPENSION AND EXCHANGE BETWEEN ROOMS.
IMPERIAL COLLEGE HAS DEVELOPED EXPERIMENTAL TECHNIQUES INVOLVING FLUORESCENT TRACERS TO STUDY THE TRANSPORT OF PARTICULATE MATERIAL AND AEROSOLS IN AND AROUND DWELLINGS (THE DIADEM SYSTEM). IN A COMPLEMENTARY DEVELOPMENT AT THE COLLEGE REACTOR CENTRE, SENSITIVE STABLE TRACER TECHNIQUES USING DYSPROSIUM LABELLED SILICA PARTICLES HAVE BEEN DEVISED.
THE EQUIPMENT DEVELOPED IS SUITABLE FOR MEASURING SPATIAL DISTRIBUTIONS OF AEROSOL PARTICLES ON SURFACES. A SUITABLE TRACER, WHICH MUST FLUORESCENCE UNDER UV LIGHT, IS CHOSEN. DISPERSION IS ARCHIEVED BY WHATEVER METHOD IS APPROPRIATE. THE SURFACE ON WHICH THE TRACER IS DEPOSITED IS ILLUMINATED BY UV LIGHT AND SCANNED BY A CCTV CAMERA. THE RESULTING IMAGE IS DIGITISED AND PROCESSED TO EXTRACT INFORMATION ON THE DISTRIBUTION OF THE TRACER. THIS INFORMATION INCLUDES THE ACTUAL MASS OF TRACER DEPOSITED ON THE SURFACE. THE PROCEDURE IS FAST, REASONABLY SENSITIVE AND PROVIDES DIRECT INFORMATION ON THE SPATIAL DISTRIBUTION OF THE TRACER WHICH IS TIME-CONSUMING BY OTHER METHODS.
THE AIM OF THE WORK IS TO YIELD DATA FOR A COMPUTER METHODOLOGY DESCRIBING THE INFILTRATION, DEPOSITION AND TRANSPORT OF PARTICULATE MATERIAL INTO AND WITHIN DWELLINGS.

THE RESEARCH WILL BE DIVIDED INTO FOUR PHASES:
1. FURTHER CALIBRATION STUDIES OF THE DIADEM TECHNIQUE AND THE STUDY OF DEPOSITION OF AEROSOLS ON VARIOUS WALL AND FLOOR COVERINGS, IN A CONTROLLED ENVIRONMENT CHAMBER.
2. CALIBRATION DEPOSITION STUDIES AGAINST RADIOACTIVE AEROSOLS OF CS-137 IN THE WIND TUNNELL (FUNDED BY U.K. MAFF) AT THE IMPERIAL COLLEGE REACTOR CENTRE.
3. ACQUISITION OF AN EXPERIMENTAL HOUSE IN CONSULTATION WITH THE U.K. PROPERTY SERVICES AGENCY AND THE BUILDING RESEARCH ESTABLISHMENT, CARRYING OUT CAREFULLY PLANNED EXPERIMENTS ON
- MECHANICAL INGRESS
- DEPOSITION OVER SURFACES
- RESUSPENSION FROM FLOOR
- WEATHERING AND TRANSPORT BETWEEN ROOMS
- EFFECTS OF CLEANING
4. TRIAL EXPERIMENTS ON INFILTRATION USING IMPERIAL COLLEGE'S RBG-1000 PARTICLE GENERATOR TO EXPOSE A HOUSE EXTERNALLY WITH STABLE TRACER BEARING AEROSOL.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

IMPERIAL COLLEGE OF SCIENCE, TECHNOLOGY AND MEDICINE
Address
Exhibition Road
SW7 2AZ London
United Kingdom