Effective radium-226 concentration, ECRa, is the product of radium activity concentration, CRa, multiplied by the emanation coefficient, E, which is probability of producing a radon-222 atom in the pore spaces. It is measured by accumulation experiments in the laboratory, achieved routinely for a sample mass >50 g using scintillation flasks to measure the radon concentration. We report on 3370 ECRa values obtained from more than 11 800 such experiments. Rocks (n=1351) have a mean ECRa value of 1.9±0.1 Bq kg−1 (90% of data in the range 0.11–35 Bq kg−1), while soils (n=1524) have a mean ECRa value of 7.5±0.2 Bq kg−1 (90% of data between 1.4 and 28 Bq kg−1). Using this large dataset, we establish that the spatial structure of ECRa is meaningful in geology or sedimentology. For plants (n=85), ECRa is generally <1 Bq kg−1, but values of larger than 10 Bq kg−1 are also observed. Dedicated experiments were performed to measure emanation, E, in plants, and we obtained values of 0.86±0.04 compared with 0.24±0.04 for sands, which leads to estimates of the radium-226 soil-to-plant transfer ratio. For most measured animal bones (n=26), ECRa is >1 Bq kg−1. Therefore, ECRa appears essential for radon modelling, health hazard assessment and also in evaluating the transfer of radium-226 to the biosphere.

We have investigated two buildings covered with Zsolnay glazed architectural ceramics in Budapest (Hungary), one located in the densely built-up area of the city centre with a high traffic rate and one in a city quarter with moderate traffic and more open space. A black crust layer, containing a large amount of artificial particulate matter with different size and chemical composition, was observed on the ceramic material of both buildings, whereas weathered glaze was detected only on the ceramics of the building situated in the city centre. In this paper, our goal is to reveal the role of the particulate matter in the degradation of architectural ceramics. For this reason the attic dust and settled dust from the roofs of the studied buildings were collected. In the attic dust, besides the natural particles of geological origin, three types of artificial particles typically with spherical shape (spherules) were also distinguished: aluminosilicate (two subtypes), carbonaceous, and iron-rich fly-ash. The appearance of gypsum crystallites around the particulate matter in association with all spherule types suggests that the particulate matter greatly contributes to the degradation process.