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1.
Carcinogenic and mutagenic polycyclic aromatic hydrocarbons (PAHs) generated in coal combustion have caused great environmental health concern. Seventeen PAHs (16 high priority PAHs recommended by USEPA plus Benzo[e]pyrene) present in five raw bituminous coals and released during bituminous coal combustion were studied. The effects of combustion temperature, gas atmosphere, and chlorine content of raw coal on PAHs formation were investigated. Two additives (copper and cupric oxide) were added when the coal was burned. The results indicated that significant quantities of PAHs were produced from incomplete combustion of coal pyrolysis products at high temperature, and that temperature is an important causative factor of PAHs formation. PAHs concentrations decrease with the increase of chlorine content in oxygen or in nitrogen atmosphere. Copper and cupric oxide additives can promote PAHs formation (especially the multi-ring PAHs) during coal combustion.  相似文献   

2.
Carcinogenic and mutagenic polycyclic aromatic hydrocarbons (PAHs) generated in coal combustion have caused great environmental health concern. Seventeen PAHs (16 high priority PAHs recommended by USEPA plus Benzo[e]pyrene) present in five raw bituminous coals and released during bituminous coal combustion were studied. The effects of combustion temperature, gas atmosphere, and chlorine content of raw coal on PAHs formation were investigated. Two additives (copper and cupric oxide) were added when the coal was burned. The results indicated that significant quantities of PAHs were produced from incomplete combustion of coal pyrolysis products at high temperature, and that temperature is an important causative factor of PAHs formation. PAHs concentrations decrease with the increase of chlorine content in oxygen or in nitrogen atmosphere. Copper and cupric oxide additives can promote PAHs formation (especially the multi-ring PAHs) during coal combustion.  相似文献   

3.
Conclusions In spite of very high toxic potency of PAH, in India environmental monitoring and assessment of PAH is rarely done compared to European countries and US. The Central Pollution Control Board (CPCB) had recently initiated regular monitoring of PAHs in ambient air in select cities. According to CPCB, ambient air PAH in Delhi ranged between 9.4–60.9 nanograms per cubic meter (ng/m3) during 1999–2000 with higher values recorded in winter. Other research studies reported about 4.999.56 ng/m3 of benzo[a]pyrene in suspended paniculate matter (SPM) during 1986 in urban Delhi. In Calcutta, sum of 12 PAHs was 22.91 and 190.96 ng/m3 in SPM at Jadavpur and Maulali respectively, in 1994. The average benzo[a]pyrene concentration was 10.4+4.76 ng/m3. These levels are apparently manifold higher than the European standards. Apart from few such studies no detailed studies are available in India. Even in the current standards and specifications for diesel engines there is no emission limit for PAH. Recently it had specified that 10% of PAH by hydrocarbons as limit that should be adopted by 2005. In the current Indian scenario, especially after the economic liberalization in 1991, the motor vehicle population is increasing rapidly, leading to corresponding increase in PAH emissions. The role of PAHs in cardiovascular mortality, cancer cases and several other health abnormalities that are reported nowadays cannot be ignored.  相似文献   

4.
通过对校园内不同下垫面雨水径流进行水质监测分析,数据显示初期雨水径流污染物浓度较高,随着降雨持续,其浓度下降并趋于平稳。结果表明,校园屋面雨水径流水质较校园道路好,雨水径流中pH、电导率、BODs、溶解氧、总余氯、氨氮、TP、度及嗅和味等指标均符合”城市杂用水标准”要求,而SS、TN、浊度等指标含量较高,超过该标准要求。  相似文献   

5.
Atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) were measured during various seasons at six different cities/locations in Qingdao alongshore. The annual average PAHs concentration ranged from 16 ng/m3 (at a clean com- pared site) to 308 ng/m3 (in an industry site). The average total particulate PAHs concentration was 74.5 ng/m3 with a higher concentration of particulate PAHs in winter. Based on a year-round dataset, the sources of PAHs in the air of Qingdao were drawn by principal factor analysis and correlation analysis. The results indicated that vehicle emissions and oil burning were the main source of PAHs in Qingdao alongshore.  相似文献   

6.
对上海市高架道路17场降雨径流进行收集监测,分析了降雨径流中10种重金属和16种多环芳烃(PAHs)的浓度.结果表明:上海市高架道路径流中10种重金属As,Se,Zn,Pb,Ni,Fe,Mn,Cr,Cu和Al的浓度范围分别为0.50~51.80,0~20.80,13.67~445.80,0~44.20,0~15.80,39.58~264.20,0~253.00,0~8.20,0~124.20,159.83~536.40μg/L.其中,Se,Pb,Mn和Al浓度值超过了其对应的基准连续浓度,而Zn和Cu则超过了其所对应的基准最大浓度.径流中多环芳烃浓度值范围为37.25~114.57ng/L,均低于对应的基准连续浓度.Zn,Cu和PAHs表现出明显的初期冲刷效应.运用改进的内梅罗指数法对径流水质进行评价,发现8场降雨径流样品水质生物毒性极强,4场生物毒性较强,3场生物毒性一般,仅有2场生物毒性较弱.因此,城市高架道路径流对水生态系统具有较高的生态风险,需对其进行净化处理.  相似文献   

7.
This work investigates the effects of exhaust gas recirculation (EGR) and operation parameters including engine speed, equivalence ratio, coolant-out temperature, and intake charge temperature on the basic characteristics of a single-cylinder homogeneous charge compression ignition (HCCI) engine powered with reformulated iso-octane fuels. The running range of iso-octane HCCI engine can be expanded to lower temperature and more load by adding di-tertiary butyl peroxide (DTBP) in the fuel. The combustion timing advances with the increase of DTBP concentrations, coolant temperature and equivalence ratio. The effects of EGR on the combustion and emissions are remarkable when the EGR rate is higher than 25%, and the combustion phase is sharply postponed and the UHC and CO emissions deteriorate. The intake charge temperature has a moderate effect on combustion and emissions when it is lower than 35°C; but the combustion timing advances, the combustion duration shortens, and sometimes it leads to knock combustion when the intake charge temperature increases to above 35°C.  相似文献   

8.
Internal exposure of university students to polycyclic aromatic hydrocarbons(PAHs)was assessed through urinary PAHs metabolites. Eight monohydroxylated PAHs(OH-PAHs)were detected with high performance liquid chromatography (HPLC). The detectable frequencies were 59%-100% for different analytes. Major components in the subjects‘ urine were 2-hydroxynaphthalene(2-OHNap, 0.60 μg/mmol creatinine), followed by hydroxyphenanthrene(ΣOH-Phe, 0.38 μg/mmol cre-atinine)and 2-hydroxyfluorene(2-OHFlu, 0.25 μg/mmol creatinine). Excretion of 1-hydroxypyrene(1-OHPyr, 0.08 μg/mmol creatinine)was almost one order of magnitude lower than the 2-OHNap level in the urine samples. Phenanthrene can be metabolized to five monohydroxy metabolites in human urine. In the present study, 1-or 9-hydroxyphenanthrene(1-or9-OHPhe)was the dominant component(79%), followed by 2-+3-OHPhe(18%)and 4-OHPhe(3%). The study indicates that 1-OHPyr may not be a good marker for total PAHs exposure, and monitoring of 2-OHNap, 2-OHFlu, 1-or 9-OHPhe and 1-OHPyr as multiple biomarkers are more suitable than only using 1-OHPyr. The levels of OH-PAHs detected in urines of students living in Shanghai are higher those of people in other countries or regions. The concentrations of urine OH-PAHs are directly related to the exposure to PAHs in the environment, indicating that Shanghai residents are at high health risk.  相似文献   

9.
In this study, a porous inserted regenerative thermal oxidizer （PRTO） system was developed for a 125 kW industrial copper-melting furnace, due to its advantages of low NOr emissions and high radiant efficiency. Zirconium dioxide （ZrOz） ce- ramic foams were placed into the combustion zone of a regenerative thermal oxidizer （RTO）. Different performance characteris- tics of the RTO and PRTO systems, including pressure drop, temperature distribution, emissions, and energy efficiency, were evaluated to study the effects of the porous inserts on non-premixed CH4 combustion. It was found that the PRTO system achieved a significant reduction in the NOx emission level and a fuel saving of approximately 30% compared to the RTO system. It is most suitable for a lean combustion process at an equivalence ratio 〈0.4 with NOx and CO emission levels within 0.002%~）.003% and 0.001%q3.002%, respectively.  相似文献   

10.
为了推动大粒径沥青碎石柔性基层在路面结构中的应用,通过室内试验的方法,对掺入橡胶粉和玻璃纤维的大粒径沥青碎石进行了抗压强度、抗拉强度、抗弯拉强度和回弹模量试验及高温稳定性能、低温性能和水稳定性实验,探讨了外掺剂种类和含量对大粒径沥青碎石力学性能和路用性能的影响。结果表明:加入外掺剂后大粒径沥青碎石ATB-30的力学性能和路用性能能完全满足规范要求,尤其是玻璃纤维对大粒径沥青碎石性能的改良效果会更加明显,在外掺剂橡胶粉和玻璃纤维的作用下,适当减少沥青用量,既能保持ATB-30力学特征和路用性能不会减弱,又降低了大粒径沥青碎石工程造价。  相似文献   

11.
In order to investigate the effects of methyl ester moiety on polycyclic aromatic hydrocarbons (PAHs) and NO x formation in biodiesel combustion, the combined models were developed based on detailed methyl butanoate (MB) oxidation model and n-butane model. Also, PAHs detailed reaction mechanism and NO x formation mechanism were added to the detailed models to form the combined models. The combined models were used to compare the combustion of n-butane and MB in a shock tube simulation to understand the effects of methyl ester moiety. The results indicated that compared with n-butane, the methyl ester moiety in MB leads to different reaction pathways, more CO and CO 2 formation and less formation of PAHs precursors such as ethylene and acetylene. In addition, a better chemical insight into the effects of methyl ester moiety on NO x formation was given, which will help to understand the combustion process of biodiesel.  相似文献   

12.
详细介绍了墨西哥哈利斯科州特拉凯帕凯市住宅开发区雨水收集系统的一种家庭模式.为了设计出一个可以为家庭提供最大水量的雨水收集系统,对雨水收集量进行了估算.基于估算出的雨水收集量,对家庭总需水量进行了计算,以便探讨雨水的可能用途.雨水收集系统的主要组成部分如下:集水区;落水管(屋顶排水管),第一冲洗水箱;水箱;渗井;泵站,过滤系统;紫外(UV)处理设备.雨水收集系统被设计成中央供水系统的一部分.介绍了雨水收集系统的设计和建设过程及其造价.通过该方式,可提供一个技术参考,从而帮助市民来设计和建设他们的雨水系统.该模式既可促进此系统在墨西哥的发展,也可为国际社会提供宝贵的经验.  相似文献   

13.
Considering the short length of building roofs, a theoretical analysis of the first flush of roof runoff was conducted based on the kinematic wave and pollutant erosion equations. This mathematical derivation with analytical solutions predicts pollutant mass first flush （MFF）, mean concentration of initial runoff （MCIF）, mean concentration of roof runoff （MCRR） with diversion of initial portion and residual mass available on the bed surface （RS） after the entire runoff under the condition of constant excess rainfall. And the effects of the associated influencing factors （roof length, roof gradient, roof surface roughness, rainfall intensity, rainfall duration, and erosion coefficients） on them were discussed while the values of parameters referred to the previous studies. The results showed that for roofs whose length is shorter than 20 m, both the increase in roof length and roof gradient and the decrease in roof surface roughness result in larger MFF and MCIF and smaller MCRR and RS, which is beneficial to water reuse and pollution reduction. The theoretical relationship between the first flush and the influencing factors may aid the planning and design of roof in terms of rainwater utilization or diffuse pollution control.  相似文献   

14.
在城市道路路面中,沥青作为一种路用结合料,被广泛地采用,成为道路建设长久使用的一种材料。但由于沥青材质本身的差异,以及受设计和施工水平的影响,沥青混凝土路面最常见的病害现象有裂缝、坑槽、泛油等,这些病害的出现严重影响了行车速度、行车安全,加大了汽车磨损,缩短了沥青路面使用寿命。文章针对沥青混凝土路面常见的病害,结合施工管理中的实践经验提出一些防治措施。  相似文献   

15.
罗丽华 《滁州学院学报》2009,11(5):125-126,128
路基不均匀沉降、基层平整度、改性沥青混合料的级配、路面摊铺机械的操作及摊铺工艺、压实工艺、接缝工艺以及检查井的设置等都是控制改性沥青砼路面平整度的主要因素。笔者根据改性沥青砼路面工程实践经验认为:只有保证施工过程中加强对这些因素的控制管理,才能确保路面的平整度符合施工规范的要求。  相似文献   

16.
结合国道324线小盈岭-马巷段工程实际,通过分析旧路病害原因,摸索与试验旧路病害处置、橡胶沥青应力吸收层及橡胶沥青混合料路面的施工工艺、施工方法、质量控制等,为旧水泥砼路面加铺沥青砼面层（即白加黑）提供了一套新的思路与工艺.  相似文献   

17.
INTRODUCTION On-road vehicles are responsible for a signifi-cant and rapidly increasing portion of the air pollution in the urban areas of China due to rapid growth of motor vehicle population. The State Environmental Protection Administration (SEPA) of China has identified motor vehicles emissions as the major source of urban air pollution in China (SEPA, 2004). As of 2004, on-road vehicles were estimated to con-tribute over 50% of the nitrogen oxides (NOx) to large city’s emissi…  相似文献   

18.
Polycyclic aromatic hydrocarbons (PAHs) are common contaminants in a municipal solid waste (MSW) composting site. Knowledge of changes in microbial structure is useful to identify particular PAH degraders. However, the microbial community in the MSW composting soil and its change associated with prolonged exposure to PAHs and subsequent biodegradation remain largely unknown. In this study, anthracene was selected as a model compound. The bacterial community structure was investigated using terminal restriction fragment length polymorphism (TRFLP) and 16S rRNA gene clone library analysis. The two bimolecular tools revealed a large shift of bacterial community structure after anthracene amendment and subsequent biodegradation. Genera Methylophilus, Mesorhizobium, and Terrimonas had potential links to anthracene biodegradation, suggesting a consortium playing an active role.  相似文献   

19.
近几年,雾霾现象日益严重和频繁,影响的范围也越来越大,给我们的健康、工作、生活带来了巨大的危害,这使其成为我们不得不面对的问题之一。雾霾的主要成因是：工厂所排放的废气,交通工具所排放的尾气,煤燃烧、烟花燃放所排放的烟尘,建筑、道路实施工地所产生的各种扬尘等。要想解决雾霾问题,我们应该完善相关法律法规,发展新能源,减少煤炭使用量,大力发展公共交通,减少汽车尾气排放,调整产业布局,加速产业升级。只有这样积极发展生态经济,才能够从根本上改变＂雾霾＂现象。  相似文献   

20.
本文测定了茂名石化公司生产的60＃道路沥青的粘温特性.得出公式lglg(V 0.6)=8.327-3.042lgT作为该沥青包装、运输、施工等的工作参数.同时采用较简便的混合法测定沥青的粘温特性.  相似文献   

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