Ventilation mode changes our safety in buses: Study on “air-rain” flow against chemical and arson attack in public transport vehicles

Objectives: Public transport vehicles (PTVs) play a decisive role in development of the urban economy. However, the safety of PTVs is threatened by the man-released chemical or arson attack. It was found that indoor air safety can be greatly improved by employing air-rain ventilation instead of the common ventilation in a PTV.

Methods: Numerical simulations and experiments have been done to prove the effectiveness of the air-rain flow against chemical attack or arson in PTVs.

Results: The research shows that, during a chemical attack, an air-rain flow of 0.1 m/s can constrain the spread of a chemical agent in a very limited zone near its source, which is far away from the passengers’ breathing area in the PTV. During an arson attack, at an air-rain flow of 0.3 m/s, most of the area in the PTV maintains a low temperature for at least 60?s during a fire, which is long enough for passenger evacuation.

Conclusion: Compared to common ventilation, the key characteristic of air-rain ventilation is its resistance to the blending effect of the air. Because of this, the spread of chemical agents, hot gas/combustion products during a fire, and fuel aerosol is constrained to a limited area in a PTV. Passengers are then protected from chemical attack, explosion of fuel aerosols, and high temperatures and smoke. Thus, we can say that this new ventilation mode increases passenger safety in buses.     

Topical application of synthetic pyrethroids to cattle as a source of persistent environmental contamination

Abstract

Following the application of permethrin or cyhalothrin to cattle for the control of ectoparasites, the occurrence and persistence of these chemicals was assessed on the animals and in their environment. The release of permethrin from ear tags containing 1g of the drug on cattle was followed for 65 days and lead to concentrations of 5 to 35 μg of permethrin per gram of hair on the shoulders. On the flanks of the animals, the corresponding values were 10 times lower. Across the 1.5 acre pasture, high concentrations of permethiin were measured at various locations and long after treatment: 6 μg/g on bark of a birch after one week, 5 μg/g on a pole of the fence after two weeks, 1 μg/g in grass from a resting site of the animal after six weeks, and 0.5 μg/g in bark of a pine tree after three month and two weeks after the animals had left the pasture. In similar assays, cyhalothrin applied to milk cows as a pour‐on preparation was monitored. One week following treatment with 0.2 g/animal, hair cut from the shoulders contained 5 μg/g of the insecticide, which disappeared with a half‐life of 12 days. Dust collected two weeks after the pour‐on treatment from the milk barn where the cows were milked twice daily contained 47 μg/g of cyhalothrin, which disappeared with a half‐life of 44 days. These results show that synthetic pyrethroids used on farm animals can be the source of widespread and persistent contamination.     

关于城市室内环境污染治理的探讨

针对关于城市室内环境污染治理的探讨问题,提出选择治理手段来控制室内环境污染,保障人体健康显得尤为重要.介绍了室内环境污染治理技术,如光催化技术、物理吸附技术、高温熏蒸技术、臭氧和空气负离子净化技术,探讨了室内污染治理存在的误区,包括过度信赖活性炭、过度信赖植物吸附、受产品宣传误导,提出了如何选择室内污染治理手段,主要包括从根本上杜绝污染、根据装修材料选择治理手段和根据房间的布局及使用功能选择治理手段.     

Photocatalytic removal of NO and NO2 using titania nanotubes synthesized by hydrothermal method

In this study, the photocatalysts of titania nanotubes(TNTs) were synthesized at different calcination temperatures using commercial Degussa TiO2(P25) as a precursor. The materials were then characterized by BET, SEM, TEM, and XRD analyses. The photocatalytic reactions with NO and NO2 under UV-A irradiation were both performed. The results showed that the photocatalytic reaction rate of NO was much faster than that of NO2, and the conversion of NO2 to nitrate was the rate-limiting step for photocatalytic removal of NOx if the nitrate produced cannot be removed continuously from the photocatalyst surface. For TNTs calcined at different temperatures, a significant enhancement was observed on the total NOx removal efficiency by TNT calcined at 500°C for both NO and NO2 photocatalytic reaction, which could be attributed to its high anatase crystallinity as well as high surface area. These two factors affect primarily on the NO2conversion step in which the high anatase crystallinity could be responsible for the high efficiency at the beginning, while the high surface area could be accounted for retaining this high efficiency from nitric acid poisoning during the test period.     

室内空气污染对人体健康的影响与保护对策

本文首先介绍了室内空气污染的定义、室内空气中常见的污染物及其主要来源,分析 了室内空气中主要污染物对人体健康的影响,从而提出了保护室内环境的对策。     

浅析室内环境污染问题及其控制

通过分析室内环境污染问题的产生原因及室内污染物对人体的种种危害，提出防治室内环境污染、改善环境质量的对策。     

室内空气污染对人体健康影响与防护对策

介绍了室内空气污染的定义、室内空气中常见的污染物及其主要来源,分析了室内空气中主要污染物对人体健康的影响, 提出了保护室内环境的对策.     

Polycyclic aromatic hydrocarbons in indoor and outdoor air in Turkey: Estimations of sources and exposure

The aim of the current study was to measure polycyclic aromatic hydrocarbons (PAHs) in eight indoor (In both kitchen and living room) air sampling locations using a passive sampling method for collection. Passive outdoor air samples were also collected from 3 of the same sampling locations as the indoor air sampling sites. Sampling was conducted in three seasons. The summer season, when windows are generally open, was between 18th July and 01st September, 2014; the autumn and winter seasons, when windows are mostly closed, was between 18^th October and 01^st December, 2014, and 01^st December, 2014, and 18^th January, 2015, respectively.

Average PAH concentrations in summer were 22 ± 21 ng/m³ and 17 ± 12 ng/m³ in the living room and kitchen, respectively, whereas living room and kitchen average PAH concentrations were 23 ± 16 ng/m³ and 20 ± 9 ng/m³, respectively, in autumn and 23 ± 13 ng/m³ and 23 ± 24 ng/m³, respectively, in winter. Outdoor air PAH concentrations in summer, autumn and winter were 7 ± 0.4 ng/m³, 22 ± 13 ng/m³ and 209 ± 33 ng/m³, respectively. An increase in outdoor PAH concentrations was measured in winter compared to the concentrations in summer and autumn, which paralleled the lower outdoor air temperature. However, PAH concentrations in the indoor environment vary according to the household characteristics and personal habits.     

玻璃表面PAHs垂向分布特征与室内外对比研究

利用GC-MS对上海市玻璃表面有机膜中PAHs浓度进行了定量分析。结果表明随着楼层的增加,10层居民楼玻璃表面PAHs浓度出现先增加后减少的趋势,最高浓度出现在3层(736 ng/m~2),最低在9层(346 ng/m2);17层公寓楼PAHs浓度则是先减少后增加再减少的趋势,最高浓度出现在9层(2 338 ng/m~2),最低在16层(564 ng/m~2)。TOC与PAHs相关性分析暗示除TOC外,玻璃表面PAHs富集可能还受控于其他因素。10层居民楼主要以3环和4环PAHs为主;而17层公寓楼则以4环为主。玻璃外表面PAHs浓度(555 ng/m~2)远高于内表面(308 ng/m~2);外表面主要以Phe、Pyr、Chry、Fluo和Fl为主;内外表面低环PAHs比值接近于1,高环比值基本上低于0.6。TEQ值虽然较低,但生态风险仍不能忽视。     

室内环境中持久性卤代有机污染物的人体暴露及潜在生殖健康影响

卤代持久性有机污染物(Hal-POPs),如多溴联苯醚(PBDEs)、多氯联苯(PCBs)、滴滴涕(DDT)等是环境中广泛存在的全球性有机污染物,同时它们又是内分泌干扰物,是威胁人类生殖健康的重要因素之一。由于人们每天约有80%以上的时间在室内度过,且室内环境是Hal-POPs人体暴露的主要来源之一,因此室内环境中Hal-POPs对人体内分泌系统的干扰作用及其机理等问题亟待研究,但目前这方面的研究很有限。本文通过综述Hal-POPs在室内环境中的赋存水平和在人体体内的负荷水平及其半衰期,探讨了其对人体内分泌系统尤其是男性生殖健康的影响情况及其可能的机理,并分析了目前研究的不足之处及研究前景,为进一步开展这方面的研究提供借鉴。