Unanswered questions on the airborne transmission of COVID-19

Environmental Chemistry Letters - Policies and measures to control pandemics are often failing. While biological factors controlling transmission are usually well explored, little is known about...     

林业资源开发与利用的现状与对策分析

在生态系统中,森林是重要的组成成分之一,在社会、经济以及人类不断发展的时代背景下,林业资源因过度的开发而受到了破坏。从现下的实际情况看来,这种现象对人们的生活并没有带来太大的影响,但是,对子孙后代却造成了无法挽回的损失,因此,需要林业部门加大对林业资源的保护以及开发利用力度,以此来确保林业资源的最大化使用,严禁出现过度开采以及浪费资源的现象。鉴于此,本文就林业资源开发与利用的现状与对策展开探讨,以期为相关工作起到参考作用。     

雾霾天气背景下大气环境监测质量的提升路径研究

本文主要针对雾霾天气背景下大气环境监测质量的提升路径展开深入研究,先阐述了大气环境监测质量的提升重要性,比如有利于提高环境污染的防治水平、有利于不断提高城市环境规划水平等,然后重点提出了几点可行的提升路径,主要包括制定大气环境监测质量保障体系、加强环境质量监测网络建设、加强大气环境监测采样管理、加强3S技术的应用、加强监测监察联动协调机制、扩大大气环境质量评价范围等,确保监测数据与完整性和准确性相符,确保大气环境监测质量的稳步提升,以创建节能减排、生态环保的节约型社会。     

Assessing the phytotoxicity of different particle-size aged refuse using Zea mays L. bioassay

With increasing attention paid to the recycling use of aged refuse as vegetated soil, it is important to check its possible polluting risk and probe the tolerance of plant system to its stress. For this reason, several physiological responses in Zea mays L. (maize) to the leaching samples of aged refuse in different particle-size (900-300, 300-150, 150-105, 105-90, and 90-0 microm) were investigated in the present study, including growth, lipid peroxidation, protein oxidation and activities of antioxidant enzymes. The results indicate that the aged refuse affected the growth of maize seedlings, and elevated the levels of lipid peroxidation and protein oxidation in leaf tissues in a time-dependent manner, accompanying by the changes of antioxidant status. Also, above physiological responses varied as a function of particle-size distribution of the aged refuse, and statistical growth inhibition and oxidative stress occurred after the exposure of smaller particle-size samples, which contained higher level trace metals, the characteristic pollutants in the aged refuse. The results implicate that aged refuse might cause environmental stress on plant system, but the polluting risk mainly resulted from smaller particle-size samples. Therefore, the critical point of utilizing aged refuse as vegetated soil focused on analyzing its particle-size distribution, and screening out appropriate particle-size samples.     

Release of polycyclic aromatic hydrocarbons from Yangtze River sediment cores during periods of simulated resuspension

The role of resuspension duration on release of 16 PAHs was measured experimentally using a particle entrainment simulator (PES). Three sediment cores were resuspended for 12h at 0.2 and 0.5N m(-2). PAHs in water column and total suspended solids (TSS) were monitored at intervals. After 0.25h of resuspension, PAH release was on average 42% of their concentrations after 12h of resuspension, indicating fast release of PAHs from sediments in an initial short time. Moreover, PAHs released faster at 0.5N m(-2) than at 0.2N m(-2); low molecular weight PAHs (2-3-ring) released faster than median molecular weight (4-ring) PAHs. PAH concentrations in TSS showed generally increase with time and differences in magnitudes based on sediment type and energy. Overall, the composition of sediments is the major factor in determining the amount of released PAHs, more so than the level of resuspension energy applied.     

等离子体与光催化复合空气净化技术研究

尝试了一种新的等离子体-光催化复合方式进行空气净化,研究表明该种复合方式具有较显著的协同促进效应,通过改变等离子体发生单元与光催化单元的距离以及在两者之间放置网状物,可消除等离子体单元产生的负电荷对光催化单元的不利影响,进一步提高其复合效应.还对这一复合方式产生协同效应的机理进行了分析.     

粉末冶金方法在块状雄黄制备过程As2O3气体污染防治中的应用

针对现有块状雄黄火法制备工艺As2 O3气体污染严重的情况 ,提出了利用粉末冶金方法热压工艺制备块状雄黄的“浮选 化学除杂 热压制块”新工艺流程。并对热压制块工艺进行了试验研究。试验结果表明 ,在较佳工艺条件下可以制备出符合药用要求的较致密的块状雄黄 ,且该工艺不会造成As2 O3气体污染。     

污泥缺氧好氧消化的减量研究

实验主要进行缺氧好氧工艺在不同运行条件下消化效果的研究;在常温和中温下,与传统污泥好氧消化处理的效果对比,并进行pH等控制参数的统计规律分析,提出优化处理工艺条件,也为污泥缺氧好氧消化工艺的设计、运行管理和进一步研究提供可靠的理论依据。     

如何实现小城镇生活垃圾资源化

小城镇生活垃圾处理应重视资源化,但小城镇生活垃圾资源化面I临城镇规模、垃圾组分、经济、技术和市场等众多因素的制约。逐一分析这些制约因素并结合实例提出了小城镇生活垃圾资源化的三种实现模式,即纳管模式、组团模式和单建模式,探讨了三种模式的适用范围。     

Physiological and biochemical responses of Microcystis aeruginosa to phosphine (PH3) under elevated CO2

Phosphine (PH₃) is an important factor driving the outbreak of cyanobacterial blooms that produce toxic microcystin threating human health. To clarify the physiological and biochemical responses of cyanobacteria to PH₃ under elevated CO₂ concentration, Microcystis aeruginosa was used in the coupling treatment of 1000 ppmv CO₂ and PH₃ at different concentrations respectively. The chlorophyll a (Chl-a), carotenoid, net photosynthetic rate and total protein of M. aeruginosa exhibited evidently increasing tendency under the coupling treatment of 1000 ppmv CO₂ and PH₃ at different concentrations (7.51 × 10^?3, 2.48 × 10^?2, 7.51 × 10^?2 mg/L). The coupling treatments resulted in the higher concentrations of Chl-a and carotenoid of M. aeruginosa, compared to those in the control and the treatment with CO₂ alone, and their enhancement increased with the increase in PH₃ concentrations. The total antioxidant capacity (T-AOC) in the coupling treatment with CO₂ and PH₃ of 2.48 × 10^?2 mg/L and 7.51 × 10^?3 mg/L showed increasing tendency, compared to the treatment with PH₃ alone. Additionally, the coupling treatment with 1000 ppmv CO₂ and PH₃ also altered the pH and DO level in the culture medium. In this regard, the coupling treatment with CO₂ and PH₃ at an appropriate concentration can enhance the resistance of M. aeruginosa to PH₃ toxicity and is beneficial to the reproduction of M. aeruginosa, presumably resulting in potential for the outbreak of cyanobacteria bloom. Given the concern about global warming and the increase in atmospheric CO₂ level, our research laid a foundation for the scientific understanding of the correlation between PH₃ and cyanobacteria blooms.