AIVC - Air Infiltration and Ventilation Centre

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Dependence of radon concentration on pressure difference in a crawl-space

Radon concentration in a crawl space remained at the same level during autumn ( 756 Bq m-3 ) and inwinter ( 767 Bq m-3 ) because both air exchange rate and negative pressure (measured across thefoundation wall) increased after a installation of a new ventilation system in the crawl space. Inaddition, relative humidity and water content remained constant in the crawl space air during the sameperiod of time. Radon entry rate was explained by the pressure difference across the crawl space wallwith percentages of 51 % (winter) and 76 % (autumn).

Radon concentrations affected by different factors in two office buildings

In the study, the factors affecting concentrations of radon vertically lines were surveyed in twolarge office buildings. Integrated concentrations of radon were determined with alpha track etchfilms (2 months) and continuous monitoring (2-6 days) was carried out with Pylon AB-5equipment. The effective air exchange rates were analysed by the tracer gas method with aninfrared analyser and rates of air flows from vents were measured with a thermoanemometer.Pressure differences were measured with a manometer and temperature differences withthermoelements.

Karst geology, radon fluctuations, and implications for measurement and mitigation

Results of an investigation into factors contributing to elevated indoor radon concentrations insupposedly mitigated homes suggest that, in areas of extensive karst geological development,fluctuations in indoor radon concentrations may be extraordinary in magnitude, duration and seasonaloccurrence.

Teaching radon in the living environment school experiments with air, liquids, and solids

The contents of an Experimental Set are presented, providing all necessary implements for novelmethods to collect, concentrate, store and measure radon and radon decay products from harmless und ubiquitous sources of air, liquids and solids. A series of experiments is described to demonstrate the essential properties of radioactivity

The radiation doses received from radon by recreational cavers using caves in the mendip hills, UK

Raised radon gas levels are known to exist in mines and Show Caves, and in the United Kingdomthe Ionising Radiations Regulations 1985 require the employer to take action to reduce radonlevels by improving ventilation or restricting access, because significant radiation doses can bereceived by workers.In the Mendip Hills, where the underlying rock gives rise to raised radon levels in domesticdwellings, there are a number of cave systems with unrestricted access to recreational cavers;including youth groups.

The cost effectiveness of radon remediation programmes in hospitals, schools and homes in radon affected areas in the UK

Radon gas is now considered to be a health hazard when found in excessive amounts in the builtenvironment. The levels of radon vary greatly, with some geographical areas having very highlevels. In the United Kingdom, Northamptonshire was declared an Affected Area in 1992, and itwas at this stage that our group first started studying radon levels and the steps taken to reducethem.The radon levels both before and after remediation were studied, together with the number ofoccupants of affected rooms, and their pattern of occupation.

The present status of the radon program in The United States of America

The indoor radon program in the US. started in the early 1970's in response to CongressionalHearings that recommended the initiation of radon measurements in certain parts of the united Stateswhere enhanced radon caused by contaminated uranium and radium tailings was suspect. In the mid1970's, the Department of Energy (DOE), Environmental Measurements Laboratory (EML),conducted the first indoor radon survey in the New York City Metropolitan area. The two year studyrecommended that radon surveys should be expanded throughout the US.

Calibration of instruments measuring radon over a large activity range

A newly built radon calibration test bench called BACCARA is presented. A method of calibrationusing a secondary 222Rn standard is described and examples of calibration are given. With thismethod, no reference instrument is needed and one obtains a more accurate determination of the222Rn volume activity.

Analysis of chaotic behavior of indoor radon concentrations

Indoor 222Rn concentrations are influenced by several factores which may change with time,thereby causing temporal fluctuations of radon concentrations in rooms.

The results of the lithuanian radon survey

A national survey of indoor radon levels in Lithuania was performed between 1995 and 1998. The main objective of this survey was to evaluate the average of indoor radon concentrations in Lithuania and to determine whether there were significant variations with different areas.