新型的汽车尾气净化催化剂效能的测试

在东风ＥＱ１４０型发动机的台架试验中，用涂覆天然沸石粉的堇青石蜂窝贵金属（Ｐｔ，Ｐｄ）催化剂进行了排气净化试验及动力性能试验，在发动机的功率及负荷特性试验条件下，测试了催化箱对发动机功率、油耗、排气阻力及噪音等的影响，测试了气中ＨＣ和ＣＯ的净化效果，结果表明，催化箱的结构是可行的，排气的净化效果良好，制作了催化箱，在新东风型和跃进１３１型货车上初步测试了其实际跑车性能。     

柴油机与柴油汽车烟度标准的发展及应用

研究了中国柴油机与柴油汽车烟度排放标准的发展和现状,分析了现行标准应用中应注意的问题,指出柴油机和柴油汽车烟度排放标准不统一,在烟度限值、试验方法、试验规程、试验仪器等方面存在较大差异.强调了自1993年以来,中国对柴油汽车的烟度排放要求并没有提高,以及出台更为严格的强制性标准和法规对在用柴油车排放监控的重要性,旨在有...     

汽车排气污染与治理的发展和动向

简介了汽车排气污染对人类健康和生态环境的影响；描述了世界汽车增长与排气污染的现状和发展趋势；综述了汽车排气催化净化技术所面临的挑战和最新研究动向。     

污染负荷及植被生物量变化对缓冲带污染物净化效果的影响

模拟上海地区农业面源污染和降雨特征，进行缓冲带污染物净化效果和植被生物量监测试验研究。结果表明：植被缓冲带对径流污染物质的净化效果明显高于空白对照，百慕大缓冲带SS截留率最高，达到74％；白花三叶草对TN、TP的净化效果最好，去除率分别为28％和25％；百慕大和白花三叶草生物量最大，栽种当年9月份，两者地上部分的生物量鲜重分别达到了6.14和6.49 kg/m²，百慕大生长速度最快，当年9月份生物量几乎达到5月份的6倍；植被生物量增长明显提高了缓冲带截留径流污染物的效果，缓冲带SS截留率与生物量成显著线性相关，而污染负荷变化对缓冲带污染物净化效果的影响很小，明显弱于植被种类和生物量的变化。     

矿化垃圾生物反应床处理奶牛场废水的工艺参数

试验考察了矿化垃圾生物反应床工艺处理奶牛场废水出水水质与配水负荷的关系。试验研究表明，出水CODcr、NH4-N浓度分别与配水负荷呈线性和指数相关；TN的去除率仅为60％左右，是选择最佳配水负荷的限制性因素；综合考虑废水处理能力和NO3-N的反硝化，配水速率可以保守选择0．09～0．11cm／h。     

转轮式洗轮机对车轮带泥的冲洗效果简

施工车辆车轮带泥是我国道路扬尘污染控制面临的共性和突出问题。为在国内推广使用洗轮机提供技术依据，通过检测工地出口外道路积尘负荷来估算转轮式洗轮机对车轮带泥的冲洗效率，并以该洗轮机作为车轮带泥检测设备，检测和统计北京市车轮带泥量。结果表明，（1）转轮式洗轮机可以将工地出口外100 m道路积尘负荷增量由64.4 g/m²降至5.9 g/m²，转轮式洗轮机对车轮带泥的冲洗效率大于90%；（2）渣土车和混凝土车车轮带泥量的平均值分别为5.1和2.2 kg/车；（3）北京市未来车轮带泥量将超过8.8万t/a，施工车辆全部经过转轮式洗轮机冲洗后，车轮带泥量可削减7.9万t/a。建议在相关法律法规中以强制性条款落实施工车辆车轮带泥机械化冲洗要求。     

转轮式洗轮机对车轮带泥的冲洗效果

施工车辆车轮带泥是我国道路扬尘污染控制面临的共性和突出问题。为在国内推广使用洗轮机提供技术依据，通过检测工地出口外道路积尘负荷来估算转轮式洗轮机对车轮带泥的冲洗效率，并以该洗轮机作为车轮带泥检测设备，检测和统计北京市车轮带泥量。结果表明，（1）转轮式洗轮机可以将工地出口外100m道路积尘负荷增量由64．4g／m2降至5．9g／m2，转轮式洗轮机对车轮带泥的冲洗效率大于90％；（2）渣土车和混凝土车车轮带泥量的平均值分别为5．1和2．2kg／车；（3）北京市未来车轮带泥量将超过8．8万t／a，施工车辆全部经过转轮式洗轮机冲洗后，车轮带泥量可削减7．9万t／a。建议在相关法律法规中以强制性条款落实施工车辆车轮带泥机械化冲洗要求。     

周期循环静止沉淀工艺处理矿井水

已有的实验和实践表明，周期循环静止沉淀工艺与常规连续进、出水的单一沉淀工艺相比，其沉淀效率明显提高，其出水水质显著改善。为了进一步研究周期循环静止沉淀工艺的性能，进行了工业性试验研究。结果表明，周期循环静止沉淀池与常规沉淀池相比具有较高的处理能力和水质澄清效果，是常规沉淀池处理能力的1.2倍；在两池循环的周期循环静止沉淀工艺中，当反应池与静止沉淀池总处理能力比为1∶1时，周期循环的静止沉淀池清水层高度为2 m、周期内清水层形成速度为1.67 mm/s、体积负荷和表面负荷较常规沉淀池均提高了20%；受反应池进水流量的冲击影响，周期循环静止沉淀工艺的静止沉淀池设置数以2～3个为最佳；周期循环静止沉淀工艺中反应静止沉淀系统不会对后续过滤单元产生水力影响。     

污泥负荷对UASB处理低浓度污水运行效果和污泥性质的影响

采用升流式厌氧污泥床（UASB）反应器处理低浓度生活污水，探讨了不同污泥负荷对运行效果及污泥性质的影响。通过考察有机物去除率、有机酸积累、污泥粒径、污泥比产甲烷活性、溶解性微生物产物（SMP）、胞外聚合物（EPS）等生化指标，得出如下结论：在受试条件下，污泥负荷率的升高不利于有机物的去除；有机酸特别是乙酸的积累，以及受基质缺乏及污泥洗脱限制的污泥积累，是影响处理效果的因素；稳定阶段污泥的胞外聚合物以紧密附着型EPS为主，污泥负荷升高将导致其浓度升高，而对SMP和松散附着型EPS没有显著影响，EPS的浓度及其组成不影响污泥性质。高的污泥负荷下污泥的产甲烷活性较高。在本实验中，F/M=0.4 g COD/（g MLSS·d）是最佳的污泥负荷条件。     

影响侧沟式膜泥法一体化OCO工艺脱氮效率的因素研究

采用侧沟式膜泥法一体化OCO工艺处理模拟生活污水，考察了DO、HRT和C/N 3种影响因素对模拟生活污水脱氮的效果。研究结果表明：在好氧区DO为2 mg/L左右、HRT=12 h、C/N为7.5左右时，具有较理想的脱氮效果，TN去除率达到了80%；试验还表明本工艺具有较强的抗冲击负荷能力。     

enforcement of diesel smoke emissions for the state of new jersey

This paper reports on the research program undertaken by the State of New Jersey to determine those tests and instruments which can be used by authorized state agencies for the enforcement of diesel smoke emissions. The state agencies under consideration for the enforcement of diesel smoke emissions are the following: (1) The Division of Motor Vehicles, in its system of state owned inspection stations, will be able to inspect all diesel-powered trucks, and tractors which are registered in New Jersey. (2) The Public Utilities Commission will be able to inspect at their home garages all buses registered in the State. (3) The New Jersey State Police will be able to inspect diesel-powered vehicles on the road. It was decided that the maximum inspection time for each vehicle was not to exceed one minute. On the basis of the one minute per vehicle requirement, eight different tests were evaluated to determine which ones correlated well with normal vehicle operation. These tests included acceleration of a fixed external inertia, free acceleration of only the moving parts of the engine, three ramp tests, a test in which a heavy vehicle was towed, and a driving test in which the vehicle being tested was actually accelerated. The results of tests demonstrated that the modified free acceleration method correlates reasonably well with a loaded steady state cycle, distinguishes the high emitters and is simple to perform. Consequently, the free acceleration test method is recommended for use in inspection stations and on the road. Finally, nearly two hundred vehicles have been tested by this procedure to determine present and potential levels of diesel smoke emissions. Another phase of the program consisted of the determination of smoke measuring techniques and instrumentation. The use and design of smokemeters were extensively investigated, as well as the use of the visual and photographic techniques. Of the various smokemeters tested for this application, several measured smoke satisfactorily in the laboratory, but none were found adequate for field use; they either lacked portability or were unstable due to the deposition of soot on the optics. At the time of writing, specifications for the necessary smokemeter have been drafted and published for bid to interested manufacturers.     

On-road and laboratory investigation of low-level PM emissions of a modern diesel particulate filter equipped diesel passenger car

Modern diesel particulate filter (DPF) systems are very effective in reducing particle emissions from diesel vehicles. In this work low-level particulate matter (PM) emissions from a DPF equipped EURO-4 diesel vehicle were studied in the emission test laboratory as well as during real-world chasing on a high-speed test track. Size and time resolved data obtained from an engine exhaust particle sizer (EEPS) and a condensation particle counter (CPC) are presented for both loaded and unloaded DPF condition. The corresponding time and size resolved emission factors were calculated for acceleration, deceleration, steady state driving and during DPF regeneration, and are compared with each other. In addition, the DPF efficiency of the tested vehicle was evaluated during the New European Driving Cycle (NEDC) by real time pre-/post-DPF measurements and was found to be 99.5% with respect to PM number concentration and 99.3% for PM mass, respectively. PM concentrations, which were measured at a distance of about 10 m behind the test car, ranged from 1 to 1.5 times background level when the vehicle was driven on the test track under normal acceleration conditions or at constant speeds below 100 kmh^?1. Only during higher speeds and full load accelerations concentrations above 3 times background level could be observed. The corresponding tests in the emission laboratory confirmed these results. During DPF regeneration the total PM number emission of nucleation mode particles was 3–4 orders of magnitude higher compared to those emitted at the same speed without regeneration, while the level of the accumulation mode particles remained about the same. The majority of the particles emitted during DPF regeneration was found to be volatile, and is suggested to originate from accumulated sulfur compounds.     

An outline of the 1994-1998 European inspection and maintenance study: part I-design, tests, and results of experimental methods.

This paper provides an overview and the main results of a study aiming to evaluate current and alternative inspection and maintenance (I/M) programs to control emissions from in-use cars in Europe. For this purpose, a large number of passenger cars from five countries (France, Germany, Greece, the Netherlands, and the United Kingdom) were tested according to a common test protocol that included a variety of driving cycles and short tests, both legislative and specifically developed for this exercise. Evaluation of all test results was conducted with the objective of defining effective I/M test procedures and examining the potential of periodic I/M programs to reduce pollutant emissions and improve fuel economy of in-use cars. The results indicate that the current idle test used for catalyst-equipped cars in Europe is probably ineffective, while short transient loaded testing was found to offer higher potential in environmental terms. Regarding conventional gasoline cars, it is concluded that the idle test is sufficient, provided that the CO cut point is reduced and an HC test is added at high idle. Finally, the effectiveness of the free acceleration smoke test for diesels is questioned, while a transient cycle with continuous opacity measurement was found to be very promising. A companion paper further uses these results to analyze the likely cost-effectiveness on a per-country basis and discusses the possible effect of maintenance on emissions.     

Effects of driving conditions on diesel exhaust particulates

Four driving conditions were examined to characterize how speeds and loads of a medium-duty diesel engine affect resultant diesel exhaust particulates (DEPs) in terms of number concentrations (< or =400 nm), size distribution, persistent free radicals, elemental carbon (EC), and organic carbon (OC). At the medium engine load (60%), DEPs surged in number concentrations at around 40-70 nm, whereas DEPs from the full engine load (100%) showed a distinctive bimodal distribution with a large population of 30-50 nm and 100-400 nm. Under the full engine load, engine speeds insignificantly affected resultant DEP number concentrations. When the engine load decreased from 100% to the medium level (60%), DEPs of ultrafine size and 100-400 nm decreased at least 1.4 times (from 5.6 x 10(8) to 4 x 10(8) #/cm3) and more than 3 times (from 2.7 x 10(8) to 0.8 x 10(8) #/cm3), respectively. The same reduction in the engine load significantly decreased persistent free radicals in DEPs up to approximately 30 times (from 123 x 10(16) to 4 x 10(16) #spin/g). Decreasing the engine load from 100 to 60% also concurrently reduced both EC and OC in total DEPs around 2 times, from 27.3 to 13.9 mg/m3, and from 17.6 to 9.2 mg/m3, respectively. For DEPs smaller than 1 microm, under the full engine load, EC and OC consistently peaked at 170-330 nm under an engine speed of 1800 rpm or 94-170 nm under an engine speed of 3000 rpm, reflecting processes of nucleation, cluster-cluster agglomeration, and condensation. Decreasing the engine load from 100 to 60% reduced EC and OC in DEPs (smaller than 1 microm) at least 3 times (0.6 to 0.2 mg/m3) and 2 times (0.4 to 0.2 mg/m3), respectively. Taken together, decreasing the full engine load to a medium (60%) level effectively reduced the number concentrations (< or =400 nm), persistent free radicals, EC, and OC of total DEPs, as well as the concentration of EC and OC in ultrafine and accumulation-mode DEPs.     

Wood smoke as a source of particle-phase organic compounds in residential areas

The objective of this study was to investigate the organic composition of wood smoke emissions and ambient air samples in order to determine the wood smoke contribution to the ambient air pollution in the residential areas. From November 2005 to March 2006 particle-phase PM₁₀ samples were collected in the residential town Dettenhausen surrounded by forests near Stuttgart in southern Germany. Samples collected on pre-baked glass fibre filters were extracted using toluene with ultrasonic bath and analysed by gas chromatography mass spectrometry (GC-MS). 21 polycyclic aromatic hydrocarbons (PAH) including 16 USEPA priority pollutants, different organic wood smoke tracers, primarily 21 species of syringol and guaiacol derivatives, levoglucosan and its isomers mannosan, galactosan and dehydroabietic acid were detected and quantified in this study. The concentrations of these compounds were compared with the fingerprints of emissions from hardwood and softwood combustion carried out in test facilities at Universitaet Stuttgart and field investigations at a wood stove during real operation in Dettenhausen. It was observed that the combustion derived PAH was detected in higher concentrations than other PAH in the ambient air PM₁₀ samples. Syringol and its derivatives were found in large amounts in hardwood burning but were not detected in softwood burning emissions. On the other hand, guaiacol and its derivatives were found in both softwood and hardwood burning emissions, but the concentrations were higher in the softwood smoke compared to hardwood smoke. So, these compounds can be used as typical tracer compounds for the different types of wood burning emissions. In ambient air samples both syringol and guaiacol derivatives were found which indicates the wood combustion contribution to the PM load in such residential areas. Levoglucosan was detected in high concentrations in all ambient PM₁₀ samples. A source apportionment modelling, Positive Matrix Factorization (PMF) was implemented to quantify the wood smoke contribution to the ambient PM₁₀ bound organic compounds in the residential area.     

Validation of a new method for measuring and continuously monitoring the efficiency of industrial flares

A new method has been developed for a direct and remote measurement of industrial flare combustion efficiency (CE). The method is based on a unique hyper-spectral or multi-spectral Infrared (IR) imager which provides a high frame rate, high spectral selectivity and high spatial resolution. The method can be deployed for short-term flare studies or for permanent installation providing real-time continuous flare CE monitoring.

In addition to the measurement of CE, the method also provides a measurement for level of smoke in the flare flame regardless of day or night. The measurements of both CE and smoke level provide the flare operator with a real-time tool to achieve “incipient smoke point” and optimize flare performance.

The feasibility of this method was first demonstrated in a bench scale test. The method was recently tested on full scale flares along with extractive sampling methods to validate the method. The full scale test included three types of flares – steam assisted, air assisted, and pressure assisted. Thirty-nine test runs were performed covering a CE range of approximately 60-100%. The results from the new method showed a strong agreement with the extractive methods (r²=0.9856 and average difference in CE measurement=0.5%).

Implications: Because industrial flares are operated in the open atmosphere, direct measurement of flare combustion efficiency (CE) has been a long-standing technological challenge. Currently flare operators do not have feedback in terms of flare CE and smoke level, and it is extremely difficult for them to optimize flare performance and reduce emissions. The new method reported in this paper could provide flare operators with real-time data for CE and smoke level so that flare operations can be optimized. In light of EPA’s focus on flare emissions and its new rules to reduce emissions from flares, this policy-relevant development in flare CE monitoring is brought to the attention of both the regulating and regulated communities.     

A Comparative Study of Aluminum Smelter Roof Vent Sampling Methods

Abstract

The purpose of the study was to quantify the impact of traffic conditions, such as free flow and congestion, on local air quality. The Borman Expressway (I-80/94) in Northwest Indiana is considered a test bed for this research because of the high volume of class 9 truck traffic traveling on it, as well as the existing and continuing installation of the Intelligent Transportation System (ITS) to improve traffic management along the highway stretch. An empirical traffic air quality (TAQ) model was developed to estimate the fine particulate matter (PM_2.5) emission factors (grams per kilometer) based solely on the measured traffic parameters, namely, average speed, average acceleration, and class 9 truck density. The TAQ model has shown better predictions that matched the measured emission factor values more than the U.S. Environmental Protection Agency (EPA)-PART5 model. During congestion (defined as flow-speeds <50 km/hr [30 mi/hr]), the TAQ model, on average, overpredicted the measured values only by a factor of 1.2, in comparison to a fourfold underprediction using the EPA-PART5 model. On the other hand, during free flow (defined as flow-speeds >80 km/hr [50 mi/hr]), the TAQ model was conservative in that it overpredicted the measured values by 1.5-fold.     

Development of an empirical model to estimate real-world fine particulate matter emission factors: the traffic air quality model

The purpose of the study was to quantify the impact of traffic conditions, such as free flow and congestion, on local air quality. The Borman Expressway (I-80/94) in Northwest Indiana is considered a test bed for this research because of the high volume of class 9 truck traffic traveling on it, as well as the existing and continuing installation of the Intelligent Transportation System (ITS) to improve traffic management along the highway stretch. An empirical traffic air quality (TAQ) model was developed to estimate the fine particulate matter (PM2.5) emission factors (grams per kilometer) based solely on the measured traffic parameters, namely, average speed, average acceleration, and class 9 truck density. The TAQ model has shown better predictions that matched the measured emission factor values more than the U.S. Environmental Protection Agency (EPA)-PART5 model. During congestion (defined as flow-speeds < 50 km/hr [30 mi/hr]), the TAQ model, on average, overpredicted the measured values only by a factor of 1.2, in comparison to a fourfold underprediction using the EPA-PART5 model. On the other hand, during free flow (defined as flow-speeds > 80 km/hr [50 mi/hr]), the TAQ model was conservative in that it overpredicted the measured values by 1.5-fold.     

Tetracycline and 4-epitetracycline modified the in vitro catabolic activity and structure of a sediment microbial community from a tropical tilapia farm idiosyncratically

Aquaculture farmers commonly add tetracycline to fish feed or to their ponds to prevent or treat bacterial infections in their crops. To assess the short-term effect of tetracycline (TET) and of one of its reversible epimers, 4-epitetracycline (ETC), on the function and structure of a sediment microbial community from a tropical tilapia farm, we contrasted community-level physiological profiles (CLPP) and phospholipid fatty acid profiles (PLFA) obtained from microcosms exposed for 12 days to 5, 10, 50, or 75 mg kg^?1of these antibiotics. Notwithstanding that the concentration of the antibiotics during the experiment decreased between 13–100% (TET) or 16–61% (ETC), both compounds provoked opposing metabolic responses that did not revert. TET displayed a tendency to inhibit respiration at concentrations < 50 mg kg^?1, whereas ETC showed the opposite effect. As revealed by the finding of the fatty acids 11:0 iso 3OH, 16:1w6c, and 18:1w6c, the sediment analyzed was predominantly colonized by Gram-negative bacteria. A marked decrease in fatty acid diversity accompanied the aforementioned metabolic responses, with TET concentrations > 50 mg kg^?1leading to an enrichment of yeast and fungal biomarkers and both antibiotics at concentrations < 10 mg kg^?1selecting for microorganisms with 11:0 iso 3OH. In agreement with CLPP data, differences between the PLFA profiles of control and treated microcosms were more pronounced for TET than for ETC. We conclude that high, yet field-relevant, concentrations of TET and ETC have the potential to modify the composition, and to a lesser extent, the functioning of a sediment microbial community. This study highlights the importance of considering antibiotic degradation products in ecotoxicological research.     

Polychlorinated dibenzo-p-dioxins, dibenzofurans, and dioxin-like polychlorinated biphenyls in rice straw smoke and their origins in Japan

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs) contained in the smoke generated from rice straw burning in post-harvest paddy fields in Japan were analyzed to determine their congener profiles. Both the apportionment of toxic equivalent (TEQ) by using indicative congeners and the comparison of the homolog profiles showed that the PCDDs/PCDFs/DL-PCBs present in the rice-straw smoke were greatly influenced by those present as impurities in pentachlorophenol (PCP) and chlornitrofen (CNP, 4-nitrophenyl-2,4,6-trichlorophenyl ether) formulations that had been widely used as herbicides in paddy fields in Japan. Further, in order to investigate the effects of paddy-field soil on the PCDDs/PCDFs/DL-PCBs present in rice-straw smoke, PCDD/PCDF/DL-PCB homolog profiles of rice straw, rice-straw smoke and paddy-field soil were compared. Rice-straw smoke was generated by burning rice straw on a stainless-steel tray in a laboratory. The results suggested that the herbicides-originated PCDDs/PCDFs/DL-PCBs and the atmospheric PCDDs/PCDFs/DL-PCBs contributed predominantly to the presence of PCDDs/PCDFs/DL-PCBs in the rice-straw smoke while the contribution of PCDDs/PCDFs/DL-PCBs formed during rice straw burning was relatively minimal. The major sources of the PCDDs/PCDFs/DL-PCBs found in the rice-straw smoke were attributed primarily to the paddy-field soil adhered to the rice straw surface and secondarily to the air taken by the rice straw. The principal component analysis supported these conclusions. It is concluded that rice straw burning at paddy fields acts as a driving force in the transfer of PCDDs/PCDFs/DL-PCBs from paddy-field soil to the atmosphere.