scholarly journals Nanoaerosols Including Radon Decay Products in Outdoor and Indoor Air at a Suburban Site

2012 ◽  
Vol 2012 ◽  
pp. 1-31 ◽  
Author(s):  
Mateja Smerajec ◽  
Janja Vaupotič
Keyword(s):  
Solar Radiation ◽  
Indoor Air ◽  
Aerosol Particles ◽  
Number Concentration ◽  
Decay Products ◽  
Activity Concentrations ◽  
Radon Decay ◽  
Opening And Closing ◽  
20 Nm ◽  
Suburban Site

Nanoaerosols have been monitored inside a kitchen and in the courtyard of a suburban farmhouse. Total number concentration and number size distribution (5–1000 nm) of general aerosol particles, as measured with a Grimm Aerosol SMPS+C 5.400 instrument outdoors, were mainly influenced by solar radiation and use of farming equipment, while, indoors, they were drastically changed by human activity in the kitchen. In contrast, activity concentrations of the short-lived radon decay products218Po,214Pb, and214Bi, both those attached to aerosol particles and those not attached, measured with a Sarad EQF3020-2 device, did not appear to be dependent on these activities, except on opening and closing of the kitchen window. Neither did a large increase in concentration of aerosol particles smaller than 10 or 20 nm, with which the unattached radon products are associated, augment the fraction of the unattached decay products significantly.

scholarly journals Radon decay products and 10–1100 nm aerosol particles in Postojna Cave

2013 ◽  
Vol 13 (3) ◽  
pp. 823-831 ◽  
Author(s):  
M. Bezek ◽  
A. Gregorič ◽  
J. Vaupotič
Keyword(s):  
Activity Concentration ◽  
Size Range ◽  
Aerosol Particles ◽  
Number Concentration ◽  
Decay Products ◽  
Calculated Dose ◽  
Radon Decay ◽  
Unattached Fraction ◽  
The Difference ◽  
Key Parameter

Abstract. At the lowest point along the tourist route in Postojna Cave, the activity concentration of radon (222Rn) decay products and the number concentration and size distribution of aerosol particles in the size range of 10–1100 nm were monitored, with the focus on the unattached fraction (fun) of radon decay products (RnDPs), a key parameter in radon dosimetry. The total number concentration of aerosols during visits in summer was lower (700 cm−3) than in winter (2800 cm−3), and was dominated by <50 nm particles (related to unattached RnDPs) in summer and by >50 nm particles (related to the attached RnDPs) in winter. This explains the higher fun values in summer (0.75) and the lower winter measurement (0.04) and, consequently, DCFD values of 43.6 and 13.1 mSv WLM−1 respectively for the calculated dose conversion factors. The difference is caused by an enhanced inflow of fresh outside air, driven in winter by the higher air temperature in the cave compared to outside, resulting in the introduction of outside aerosol particles into the cave.

scholarly journals Impacts of organic aerosols and its oxidation level on CCN activity from measurement at a suburban site in China

2016 ◽  
Vol 16 (8) ◽  
pp. 5413-5425 ◽  
Author(s):  
Fang Zhang ◽  
Zhanqing Li ◽  
Yanan Li ◽  
Yele Sun ◽  
Zhenzhu Wang ◽  
...  
Keyword(s):  
Organic Material ◽  
Volume Fraction ◽  
Aerosol Particles ◽  
Strong Dependence ◽  
Organic Aerosols ◽  
Number Concentration ◽  
Accurate Estimation ◽  
Oxidation Level ◽  
Suburban Site ◽  
Ccn Activity

Abstract. This study is concerned with the impacts of organic aerosols on cloud condensation nuclei (CCN) activity based on field measurements made at a suburban site in Northern China. The sensitivity of the estimated CCN number concentration (NCCN) to both volume fraction of organic material (xorg) and aerosol oxidation level (using f44, the fraction of m∕z 44 in aerosol organic material) are examined. A strong dependence of CCN number concentration (NCCN) on the xorg and f44 was noted. The sensitivity of NCCN to volume fraction of organics increased with increasing xorg. The impacts of the aerosol particles oxidization or aging level on estimating NCCN were also very significant. When the particles were mostly composed of organics (xorg > 60 %), the NCCN at the supersaturation of 0.075 and 0.13 % was underestimated by 46 and 44 %, respectively, if aerosol particles were freshly emitted with primary organics (f44 < 11 %); the underestimation decreased to 32 and 23 % at the corresponding supersaturations, however, if the particles were with more hygroscopic secondary organics (f44 > 15 %). The NCCN at the supersaturation of 0.76 % was underestimated by 11 and 4 %, respectively, at f44 < 11 and f44 > 15 %. However, for the particles composed of low organics (e.g., xorg < 40 %), the effect caused by the f44 was quite insignificant both at high and low supersaturations. This is because the overall hygroscopicity of the particles is dominated by inorganics such as sulfate and nitrate, which are more hygroscopic than organic compounds. Our results indicated that it would decrease the uncertainties in estimating NCCN and lead to a more accurate estimation of NCCN to increase the proportion of secondary organics, especially when the composition of the aerosols is dominated by organics. The applicability of the CCN activation spectrum obtained at Xinzhou to the Xianghe site, about 400 km to the northeast of Xinzhou, was investigated, with the aim of further examining the sensitivity of NCCN to aerosol type. Overall, the mean CCN efficiency spectrum derived from Xinzhou performs well at Xianghe when the supersaturation levels are > 0.2 % (overestimation of 2–4 %). However, NCCN was overestimated by  ∼  20 % at supersaturation levels of < 0.1 %. This suggests that the overestimation is mainly due to the smaller proportion of aged and oxidized organic aerosols present at Xianghe compared to Xinzhou.

EFFECT OF WORKING CONDITIONS AND NATURAL RADIOACTIVITY LEVELS ON OCCUPATIONAL DOSES TO WORKERS OF AN OLD MANGANESE MINE

2020 ◽  
Vol 190 (3) ◽  
pp. 331-341
Author(s):  
Mohamed H E Monged
Keyword(s):  
Natural Radionuclides ◽  
Dose Assessment ◽  
Dose Equivalent ◽  
Rock Samples ◽  
Decay Products ◽  
Activity Concentrations ◽  
Radon Decay ◽  
Average Activity ◽  
Radiological Dose ◽  
Good Agreement

Abstract The aim of this work was to use RESRAD-Build model to predict the resulting external and internal radiological doses received by the workers of manganese mine located in Southern Sinai. In order to achieve that goal, measurement of the activity concentrations of natural radionuclides in rock samples collected from the inside gallery of such mine, using hyper pure germanium (HPGe) detector. Radon gas concentrations were also measured. The average activity concentrations of 238U, 226Ra, 232Th, 40K and 210Pb in rock samples were 207.3, 155.5, 59.7, 304.5 and 119.3 Bq kg–1, respectively. The average radon activity concentration was 1254.6 Bqm−3, which is equivalent to 0.135 WL. The radon concentration increases further as going deep inside the mine up to 6238 Bqm−3. RESRAD-Build model occupational effective dose equivalent (EDE) received by the workers, from natural radionuclides, dominated by 222Rn emanated from the parent nuclide 226Ra.There was good agreement between the occupational annual EDE calculated from the measured rock samples and that predicted by modeling, with estimated values of 83.8 and 82.1 mSvy−1, respectively. This radiological dose assessment indicated the predominance of internal pathways owing to radon decay products, in both cases (measured and modeled). The occupational radiological dose from the inhalation of radon and radon decay products resulted in a high lung cancer risk based on the current measurements and ventilation conditions within the mine.

scholarly journals Radon Adsorption in Charcoal

2021 ◽  
Vol 18 (9) ◽  
pp. 4454
Author(s):  
Andreas Maier ◽  
Jesse Jones ◽  
Sonja Sternkopf ◽  
Erik Friedrich ◽  
Claudia Fournier ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Strong Dependence ◽  
Radon Activity ◽  
Cancer Induction ◽  
Decay Products ◽  
Activity Concentrations ◽  
Maximum Value ◽  
Subsequent Exposure ◽  
Radon Decay ◽  
Cost Efficient

Radon is pervasive in our environment and the second leading cause of lung cancer induction after smoking. Therefore, the measurement of radon activity concentrations in homes is important. The use of charcoal is an easy and cost-efficient method for this purpose, as radon can bind to charcoal via Van der Waals interaction. Admittedly, there are potential influencing factors during exposure that can distort the results and need to be investigated. Consequently, charcoal was exposed in a radon chamber at different parameters. Afterward, the activity of the radon decay products 214Pb and 214Bi was measured and extrapolated to the initial radon activity in the sample. After an exposure of 1 h, around 94% of the maximum value was attained and used as a limit for the subsequent exposure time. Charcoal was exposed at differing humidity ranging from 5 to 94%, but no influence on radon adsorption could be detected. If the samples were not sealed after exposure, radon desorbed with an effective half-life of around 31 h. There is also a strong dependence of radon uptake on the chemical structure of the recipient material, which is interesting for biological materials or diffusion barriers as this determines accumulation and transport.

Exposure to radon/radon decay products in water works

2001 ◽  
Vol 272 (1-3) ◽  
pp. 347-348 ◽  
Author(s):  
J Schmitz ◽  
R.M Nickels
Keyword(s):  
Decay Products ◽  
Radon Decay

Determination of the concentration of aerosols of short-lived radon decay products

Atomic Energy ◽  
1962 ◽  
Vol 12 (4) ◽  
pp. 359-361
Author(s):  
N. P. Kattashov ◽  
G. A. Popov
Keyword(s):  
Decay Products ◽  
Radon Decay

Potential sources affecting the activity concentrations of 238U, 235U, 232Th and some decay products in lettuce and wheat samples

2012 ◽  
Vol 14 (11) ◽  
pp. 2902 ◽  
Author(s):  
M. Jeambrun ◽  
L. Pourcelot ◽  
C. Mercat ◽  
B. Boulet ◽  
E. Pelt ◽  
...  
Keyword(s):  
Decay Products ◽  
Activity Concentrations ◽  
Potential Sources

scholarly journals Atmospheric new particle formation at the research station Melpitz, Germany: connection with gaseous precursors and meteorological parameters

2018 ◽  
Vol 18 (3) ◽  
pp. 1835-1861 ◽  
Author(s):  
Johannes Größ ◽  
Amar Hamed ◽  
André Sonntag ◽  
Gerald Spindler ◽  
Hanna Elina Manninen ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Solar Radiation ◽  
Gas Phase ◽  
Meteorological Parameters ◽  
Particle Formation ◽  
Number Concentration ◽  
Independent Effect ◽  
Research Station ◽  
New Particle Formation ◽  
Automated Method

Abstract. This paper revisits the atmospheric new particle formation (NPF) process in the polluted Central European troposphere, focusing on the connection with gas-phase precursors and meteorological parameters. Observations were made at the research station Melpitz (former East Germany) between 2008 and 2011 involving a neutral cluster and air ion spectrometer (NAIS). Particle formation events were classified by a new automated method based on the convolution integral of particle number concentration in the diameter interval 2–20 nm. To study the relevance of gaseous sulfuric acid as a precursor for nucleation, a proxy was derived on the basis of direct measurements during a 1-month campaign in May 2008. As a major result, the number concentration of freshly produced particles correlated significantly with the concentration of sulfur dioxide as the main precursor of sulfuric acid. The condensation sink, a factor potentially inhibiting NPF events, played a subordinate role only. The same held for experimentally determined ammonia concentrations. The analysis of meteorological parameters confirmed the absolute need for solar radiation to induce NPF events and demonstrated the presence of significant turbulence during those events. Due to its tight correlation with solar radiation, however, an independent effect of turbulence for NPF could not be established. Based on the diurnal evolution of aerosol, gas-phase, and meteorological parameters near the ground, we further conclude that the particle formation process is likely to start in elevated parts of the boundary layer rather than near ground level.

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