Escaping radioactivity from coal-fired power plants (CPPs) due to coal burning and the associated hazards: a review

Coal, like most materials found in nature, contains trace quantities of the naturally occurring primordial radionuclides, i.e. of ⁴⁰K and of ²³⁸U, ²³²Th and their decay products. Therefore, the combustion of coal results in the released into the environment of some natural radioactivity (1.48 TBq y⁻¹), the major part of which (99 %) escapes as very fine particles, while the rest in fly ash. The activity concentrations of natural radionuclides measured in coals originated from coal mines in Greece varied from 117 to 435 Bq kg⁻¹ for ²³⁸U, from 44 to 255 Bq kg⁻¹ for ²²⁶Ra, from 59 to 205 Bq kg⁻¹ for ²¹⁰Pb, from 9 to 41 Bq kg⁻¹ for ²²⁸Ra (²³²Th) and from 59 to 227 Bq kg⁻¹ for ⁴⁰K. Fly ash escapes from the stacks of coal-fired power plants in a percentage of 3-1% of the total fly ash, in the better case. The natural radionuclide concentrations measured in fly ash produced and retained or escaped from coal-fired power plants in Greece varied from 263 to 950 Bq kg⁻¹ for ²³⁸U, from 142 to 605 Bq kg⁻¹ for ²²⁶Ra, from 133 to 428 Bq kg⁻¹ for ²¹⁰Pb, from 27 to 68 Bq kg⁻¹ for ²²⁸Ra (²³²Th) and from 204 to 382 Bq kg⁻¹ for ⁴⁰K. About 5% of the total ash produced in the coal-fired power plants is used as substitute of cement in concrete for the construction of dwellings, and may affect indoor radiation doses from external irradiation and the inhalation of radon decay products (internal irradiation) is the most significant. The resulting normalized collective effective doses were 6 and 0.5 man-Sv (GW a)⁻¹ for typical old and modern coal-fired power plants, respectively.     

区域大气污染物总量控制技术与示范研究

分析了我国的大气环境问题和特征,剖析了大气污染的成因;重点介绍了区域大气污染物总量控制技术研究中,大气污染物排放清单的编制技术,多尺度的空气质量模拟技术,基于现代控制理论的大气环境容量优化技术,基于环境容量和排放绩效的总量分配技术,多种总量监控方法,科学有效的总量控制管理机制和规则等的关键技术、技术突破、主要研究与理论创新及成果的应用与示范;紧密结合国家空气环境质量管理和大气污染控制的需要,提出了我国大气环境管理、政策和大气环境科学研究的建议.      

Unified correlations for vent sizing of enclosures at atmospheric and elevated pressures

Innovative vent sizing technology is presented for explosion safety design of equipment at atmospheric and elevated initial pressures. Unified correlations for vent sizing are suggested. They are modifications of previously reported correlations verified thoroughly for experimental data on vented gaseous deflagrations under different conditions but only at initial atmospheric pressure. Suggested correlations are based on experimental data on vented deflagrations of quiescent and turbulent propane–air mixtures at initial pressures up to 0.7 MPa. Typical values of turbulence factor and deflagration–outflow interaction number are obtained for experimental vented deflagrations at initial pressures higher than atmospheric.

“Blind” examination of new vent sizing technology on another set of experiments with methane–air and propane–air mixtures has shown that predictions by suggested vent sizing technology are better than by the NFPA 68 guide for “Venting of Deflagrations”.

In the development of recently reported results for initial atmospheric pressure it has been concluded that the innovative vent sizing technology is more reliable compared to the NFPA 68 guide at elevated initial pressures as well. Moreover it is crucial that the calculation procedure remains the same for arbitrary deflagration conditions.     

重庆主城区大气环境二噁英污染状况研究

二噁英污染是世界普遍关注的一个焦点问题,本文对重庆市主城区大气环境二噁英污染状况进行了研究,研究发现:重庆大气二噁英污染浓度为0.03~0.403pg TEQ/m^3,低于日本空气质量标准0.6pg TEQ/m^3,和北京、上海、广州等城市大气环境二噁英浓度相当;其污染浓度分布和当地环境有着一定的关联性,受高温工业影响比较明显。     

A review of Space-Air-Ground integrated remote sensing techniques for atmospheric monitoring

Currently, the three-dimensional (3D) distribution and characteristics of air pollution cannot be understood based on the application of any single atmospheric monitoring technology. Long-term, high-precision and large-scale 3D atmospheric monitoring might become practical by combining heterogeneous modern technologies; for this purpose, the SpaceAir-Ground integrated system is a promising concept. In this system, optical remote sensing technologies employing fixed or mobile platforms are used a...     

城市大气环境治理创新模式及方法

在经济快速发展与工业进程加快的推动下,人们生活条件得到改善。然而,大气污染问题也随之加剧,使城市形象受到严重损害,并阻碍城市发展与进步。相关部门需要对此种问题加以重视,积极制定防治措施。本文对大气污染危害与成因进行简单分析,并对其治理创新模式和方法进行简单介绍。     

Lichen-based critical loads for atmospheric nitrogen deposition in Western Oregon and Washington Forests, USA

Critical loads (CLs) define maximum atmospheric deposition levels apparently preventative of ecosystem harm. We present first nitrogen CLs for northwestern North America’s maritime forests. Using multiple linear regression, we related epiphytic-macrolichen community composition to: 1) wet deposition from the National Atmospheric Deposition Program, 2) wet, dry, and total N deposition from the Communities Multi-Scale Air Quality model, and 3) ambient particulate N from Interagency Monitoring of Protected Visual Environments (IMPROVE). Sensitive species declines of 20-40% were associated with CLs of 1-4 and 3-9 kg N ha⁻¹ y⁻¹ in wet and total deposition. CLs increased with precipitation across the landscape, presumably from dilution or leaching of depositional N. Tight linear correlation between lichen and IMPROVE data suggests a simple screening tool for CL exceedance in US Class I areas. The total N model replicated several US and European lichen CLs and may therefore be helpful in estimating other temperate-forest lichen CLs.     

Phenol transformation induced by UVA photolysis of the complex FeCl<Superscript>2+</Superscript>

Here we show that the photolysis of FeCl²⁺ upon UV irradiation of Fe(III) at pH 0.5, yielding Cl^• and then Cl₂^−•, upon further reaction with Cl⁻, induces phenol degradation. The photolysis of FeCl²⁺ can be highlighted and studied as the huge interference by FeOH²⁺ can be avoided under such conditions. Our data allowed the assessment of a photolysis quantum yield for FeCl²⁺ of 5.8 × 10⁻⁴ under UVA irradiation, much lower compared to the literature value of 0.5. The discrepancy can be explained if the photolysis process is efficient but photoformed Fe²⁺ and Cl^• undergo recombination inside the solvent cage.     

V-shaped substrate for surface and volume enhanced Raman spectroscopic analysis of microplastics

● V-shaped substrate was obtained for SERS analysis of microplastics (diameter ≈ 1 μm). ● Enhancement factor of V-shaped substrate can reach 20 in microplastics detection. ● V-shaped nanopore array can bring additional volume enhancement. ● V-shaped substrate was more economic in application compared to Klarite substrate. Research on the microplastics (MPs) is developing towards smaller size, but corresponding methods for the rapid and accurate detection of microplastics, especially nanoplastics still present challenge. In this work, a novel surface and volume enhanced Raman spectroscopy substrate was developed for the rapid detection of microplastic particles below 5 μm. The gold nanoparticles (NPs) were deposited onto the surface and into the V-shaped nanopores of anodized aluminum oxide (AAO) through magnetron sputtering or ion sputtering, and then AuNPs@V-shaped AAO SERS substrate was obtained and studied for microplastic detection. SERS performance of AuNPs@V-shaped AAO SERS substrate was evaluated through the detection of polystyrene and polymethyl methacrylate microspheres. Results indicated that individual polystyrene sphere with a diameter of 1 μm can be well detected on AuNPs@V-shaped AAO SERS substrate, and the maximum enhancement factor (EF) can reach 20. In addition, microplastics in ambient atmospheric samples were collected and tested to verify the effectiveness of the AuNPs@V-shaped AAO SERS substrate in the real environment. This study provides a rapid, economic and simple method for detecting and identifying microplastics with small size.     

Monitoring of air pollution by polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans of pine needles in Korea

The atmospheric contamination levels of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were evaluated from the analysis of pine needles in South Korea. Pine needles were collected from 30 sampling points at five main cities in South Korea (Busan, Daegu, Gwangju, Changwon and Jeju island). The highest concentrations of PCDDs/DFs (2.19–26.88 pg I-TEQ/g of dry weight) were measured at Busan, where is the city of the highest population density and traffic volume among five cities. The lowest concentration was detected at Jeju with 0.62 pg I-TEQ/g dry weight, suggesting Jeju could be an environmental background area in Korea. The dominant homologues of PCDDs/DFs in pine needles were the lower chlorine-substituted compounds such as tetra CDDs and CDFs, and the distribution ratios of PCDDs/DFs decreased with increase of the number of chlorine substituents. Homologue profiles of pine needle samples were similar to PCDDs/DFs profiles of the vapor phase in the ambient air, and thus the pine needles absorbed the vapor phase of PCDDs/DFs from air. Results suggested that pine needles could be used as an indicator of the atmospheric contamination for PCDDs/DFs in Korea.