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1

Estimation of the share of artificial Po-210 contamination in the ambient air

Długosz-Lisiecka Magdalena, Nowak Karolina

Archives of Environmental Protection

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2021

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Vol. 47, no. 1

61--68

EN

In this work, source apportionment for unsupported 210Po was conducted. The activity size distributions of both supported and unsupported 210Po in urban aerosols were measured from February to December 2019. The results confirmed that the activity of 210Po in the atmosphere is significantly increased by additional 210Po content related to coal combustion by-product releases, especially in the cold winter season. The sources of this content are local emissions and long-range transport processes. Unsupported activity concentrations of 210Po and weather parameters (temperature, humidity, and wind velocity) were used for source apportionment from three heating systems.

PL

W pracy dokonano podziału źródeł dodatkowych porcji izotopu Po-210. Rozkłady wielkości frakcji zarówno związanej, jak i niezwiązanej Po-210 w aerozolach miejskich mierzono od lutego do grudnia 2019 r. Wyniki potwierdziły, że aktywność Po-210 w atmosferze jest istotnie zwiększona przez dopływ dodatkowych porcji Po-210 związanych z uwalnianiem produktów spalania węgla, zwłaszcza w okresie zimowym. Próbki pobierano w centrum Łodzi, w Polsce. Dwie lokalne elektrownie opalane węglem kamiennym znajdują się około 7 km (205 MW) i 11 km (200 MW) od punktu poboru próbek. W odległości 70 km od punktu poboru próbek znajduje się duża elektrownia na węgiel brunatny (Elektrownia Bełchatów) o mocy 5100 MW. Aerozole zbierano na filtrach z włókna szklanego za pomocą impaktora kaskadowego (TISH). Produkty rozpadu radonu -222, tj. Pb-210, Bi-210 i Po-210 są łatwo adsorbowane na powierzchni cząstek aerozolu zawieszonych w powietrzu i chociaż aktywność 210Pb nie zmienia się znacząco ze względu na stosunkowo długi okres półtrwania wynoszący 22,3 lat, to aktywności Bi-210 i Po-210 przyrastają w czasie przebywania cząstek aerozolu w powietrzu. Temperaturę, wilgotność i prędkość wiatru analizowano wspólnie za pomocą parametru Z, który został zdefiniowany na potrzeby niniejszych badań. Obliczono związane i niezwiązane stężenia aktywności Po-210, a skorelowanie ich z parametrem Z pozwoliło określić ilościowo udział źródeł lokalnej dodatkowej porcji Po-210 i innych źródeł dodatkowej, antropogenicznej emisji Po-210, związanej z transportem dalekiego zasięgu.

2

Effect of electronic cigarette (EC) aerosols on particle size distribution in indoor air and in a radon chamber

Khalaf Hyam Nazmy, Mostafa Mostafa Y. A., Zhukovsky Michael

Nukleonika

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2019

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Vol. 64, No. 1

31--38

EN

Particle size distribution is an important factor governing whether aerosols can be deposited in various respiratory tract regions in humans. Recently, electronic cigarette (EC), as the alternative of tobacco cigarette, has become increasingly popular all over the world. However, emissions from ECs may contribute to both indoor and outdoor air pollution; moreover, comments about their safety remain controversial, and the number of users is increasing rapidly. In this investigation, aerosols were generated from ECs and studied in the indoor air and in a chamber under controlled conditions of radon concentration. The generated aerosols were characterized in terms of particle number concentrations, size, and activity distributions by using aerosol diffusion spectrometer (ADS), diffusion battery, and cascade impactor. The range of ADS assessment was from 10–3 µm to 10 µm. The number concentration of the injected aerosol particles was between 40 000 and 100 000 particles/cm3. The distribution of these particles was the most within the ultrafi ne particle size range (0–0.2 µm), and the other particle were in the size range from 0.3 µm to 1 µm. The surface area distribution and the mass size distribution are presented and compared with bimodal distribution. In the radon chamber, all distributions were clearly bimodal, as the free radon decay product was approximately 1 nm in diameter, with a fraction of 0.7 for a clean chamber (without any additional source of aerosols). The attached fraction with the aerosol particles from the ECs had a size not exceeding 1.0 µm.

3

Size distribution of ambient and radioactive aerosols formed by the shortlived radon progeny

Skubacz Krystian, Wołoszczuk Katarzyna

Journal of Sustainable Mining

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2019

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Vol. 18, iss. 2

61--66

EN

The survey of ambient airborne particle size distribution is important when the deposition of radioactive particles is considered in the human lung and the assessment of radiation hazard in occupational exposures or contaminated environments. CLOR (the Central Laboratory for Radiological Protection) in cooperation with CMI (the Central Mining Institute) performed simultaneous measurements of the activity size distribution of radon progeny and ambient aerosols using different types of aerosols. Measurements were performed in a radon chamber with a volume of 17m3, where radon was generated by a radium-226 open source, and ambient aerosols by an oil candle, vax candle, and incense sticks. Such measurements were also made in an aerosol depleted atmosphere after cleaning the chamber air by means of a high-efficiency pump and filters. The size distribution of radioactive aerosols containing radon progeny was measured by RPPSS (Radon Progeny Particle Size Spectrometer) with the measuring size ranging from 0.6 nm to approximately 2500 nm. The key parts of this device are the impaction plates and diffusion screen batteries, which collect aerosols of different sizes, and semiconductor alpha detectors which detect the activity of the collected particles. The SMPS (Scanning Mobility Particle Sizer Spectrometer) and APS (Aerodynamic Particle Sizer) were applied to evaluate the size distribution of all aerosols with sizes from approximately 3 nm to 20 μm. Based on the results obtained by these spectrometers, the activity size distributions and related dose conversion factors (DCF) were evaluated both for the exposed workers and the general population.