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Projects / Programmes source: ARIS

Physico - chemical processes involved in formation of radioactive nano aerosols

Research activity

Code Science Field Subfield
1.04.00  Natural sciences and mathematics  Chemistry   

Code Science Field
P003  Natural sciences and mathematics  Chemistry 
Keywords
radon progeny, unattached fraction, attached fraction, nano aerosols, dosimetry
Evaluation (rules)
source: COBISS
Researchers (7)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  29524  PhD Asta Gregorič  Geology  Junior researcher  2008 - 2011  184 
2.  29295  PhD Ivan Iskra  Materials science and technology  Technical associate  2008 - 2011  67 
3.  07560  PhD Maja Remškar  Physics  Researcher  2008 - 2009  830 
4.  22137  Bernarda Urankar  Educational studies  Researcher  2010 - 2011  26 
5.  10968  PhD Janja Vaupotič  Chemistry  Head  2008 - 2011  604 
6.  18290  PhD Polona Vreča  Geology  Researcher  2008 - 2011  699 
7.  15729  Stojan Žigon    Technical associate  2008 - 2011  315 
Organisations (1)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0106  Jožef Stefan Institute  Ljubljana  5051606000  90,682 
Abstract
Concentrationss of radon (Rn) and radon short-lived decay products (RnDP), factor of radioactive equilibrium (F) between Rn and RnDP, and unattached fraction (fun) of nanosize RnDP in the air, with the emphasis on the latter, will be measured in dwellings, public buildings, karst caves and spas. In addition, environmental parameters (air temperature, relative humidity and pressure) will be recorded and their influence studied on the above mentioned measured parameters. Our great interest will be the conditions of formation of nanosize unattached RnDP and of defining the size distribution of aerosols, and thus defining the fun values. We will intend to characterize the nature of the RnDP – aerosol bonding. For that purpose, measurements will be also carried out in the indoor and outdoor air at some activities, where dust particulates are produced and emitted in the atmosphere (industrial plants, traffic). Also here, nanosize aerosols will be of our focal point. Based on the measured fun values, dose conversion factors will be calculated, applying the available dosimetric models, and the values so obtained will be compared to the values of dose conversion factors revealed from the epidemiological studies.
Significance for science
Radon dosimetry is still in the process of development. One of the key question, not yet resolved, is why are the dose conversion factors (and thus doses) obtain by applying dosimetry models (DCF-D) for a factor higher than those deduced from results of epidemiologic studies (DCF-E). A prerequisite to discuss on this problem is primarily a good database on the levels of RnDP activity concentration and fraction of the unattached RnDP in different environments, under different living habits and working regime. Experimental work is mostly limited to laboratories and model houses. We see our advantage in conducting experiments in real environment. Thus, we believe to have significantly contributed to the database. Our findings have shown for a closed system of a karst cave with low aerosol concentration, how the number concentration and size distribution of general aerosols influence the formation of RnDP and their distribution to the unattached and attached form. The DCF-D values obtained from the measured fun values will further stimulate discussion on the gap between DCF-D and DCF-E. Our results on radon in soil gas and in air at faults in the caves enrich our knowledge on the influence of seismic and tectonic activities on the transport of radon.
Significance for the country
Our results may contribute to the development of Slovenia from several aspects: a) First measurements of concentration and size distribution of aerosols in the size ranges of 5–350 nm and 10–1100 nm have been carried out in Slovenia in selected environments (cave, dwelling, spa) and at selected sources (highways, crossroads and at various processes in workshops and laboratories); thus, an additional parameter to monitor air quality and to identify nano aerosol sources has been introduced, b) These data may be used by governmental bodies in preparing legislative regulation of this field, c) Results in the Postojna Cave will help the management in planning time limitation for tourist guides, d) Methodology developed at the Raven fault may be an advice how to locate other faults in Slovenia, e) The obtained radon levels in outdoor air, soil and karst caves may contribute addition knowledge of geology and tectonics in Slovenia.
Most important scientific results Annual report 2008, 2009, final report, complete report on dLib.si
Most important socioeconomically and culturally relevant results Annual report 2008, 2009, final report, complete report on dLib.si
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