High NO2/NOx emissions downstream of the catalytic diesel particulate filter: An influencing factor study

Diesel vehicles are responsible for most of the traffic-related nitrogen oxide (NO_x) emissions, including nitric oxide (NO) and nitrogen dioxide (NO₂). The use of after-treatment devices increases the risk of high NO₂/NO_x emissions from diesel engines. In order to investigate the factors influencing NO₂/NO_x emissions, an emission experiment was carried out on a high pressure common-rail, turbocharged diesel engine with a catalytic diesel particulate filter (CDPF). NO₂ was measured by a non-dispersive ultraviolet analyzer with raw exhaust sampling. The experimental results show that the NO₂/NO_x ratios downstream of the CDPF range around 20%–83%, which are significantly higher than those upstream of the CDPF. The exhaust temperature is a decisive factor influencing the NO₂/NO_x emissions. The maximum NO₂/NO_x emission appears at the exhaust temperature of 350°C. The space velocity, engine-out PM/NO_x ratio (mass based) and CO conversion ratio are secondary factors. At a constant exhaust temperature, the NO₂/NO_x emissions decreased with increasing space velocity and engine-out PM/NO_x ratio. When the CO conversion ratios range from 80% to 90%, the NO₂/NO_x emissions remain at a high level.     

电感耦合等离子体原子发射光谱法测定废气中的铅方法研究

以石英纤维滤筒采样,采用硝酸一氢氟酸消解体系,建立了电感槌合等离子体原子发射光谱法测定废气中铅分析方法。研究了仪器工作条件、方法的干扰和消除因素,探讨了空白实验对分析结果的影响;在选定的最优条件下。铅标准曲线的线性相关系数为0．9999;检出限为0．010mg／L;平均相对标准偏差为2．8％;加标回收率为97．8％～104％。与国家标准方法相比,本方法准确可靠,检测限更低,灵敏度更高,线性范围更宽,可用于废气中铅的含量测定。     

低温等离子体技术在汽车尾气净化中的应用

介绍了低温等离子体技术及在汽车尾气净化中的应用和发展现状,阐述了低温等离子体产生的方法,讨论了其在汽车尾气净化过程中的机理,并提出了目前该技术在实际应用中还存在的一些局限性。     

气相色谱法测定合成革废气中的二甲胺

采用美国NIOSH method 2010方法用气相色谱仪对合成革废气中的二甲胺浓度进行测定,对仪器条件进行优化,方法的栓出限为0.5mg/m3,相对标准偏差1.23%,回收率为85.0%-94.6%.同时在采样方法上对高浓度二甲胺废气的硅胶穿透问题进行研究,提出用含硫酸0.1mol/L的水溶液做吸收液对二甲胺废气进行吸收采样,在一定程度上解决了高浓度废气样品的穿透问题.     

遥感法与高怠速法尾气排放状况对照检测试验研究

募集100辆点燃式发动机在用汽车进行遥感法和高怠速法尾气排放对照检测试验。结果表明,多数车辆CO遥测值比高怠速值大,HC则相反。通过对高怠速值(y)与遥测值(x)进行回归分析,得到CO的回归方程为y=0.81x+453.03,t检验显示方程具有线性(α=0.10)。如果将两种方法配合使用,可以有效提高机动车尾气排放日常管理的效果。     

固定污染源废气中氟化物监测的探讨

废气固定污染源氟化物监测已有方法标准,但在实际工作中仍会遇到一些现有标准未具体规定但又严重影响监测结果的问题。文章主要针对固定污染源废气中氟化物监测时采样管的选择以及在高湿烟气中的测试进行了一些探讨,对实际工作具有指导作用。     

机动车尾气与雾霾天气

从雾和霾形成的原因以及与机动车尾气的关系等方面的论述,阐述了机动车尾气对人体健康的危害,提出了对机动车尾气的预防、治理办法。     

上海花园饭店污水处理装置的改进

1 概况 上海花园饭店,污水处理装置的全套设备从日本进口,占地面积约636m~2,采用接触曝气法处理污水。整套设施的主要技术指标包括:纳污量:800m~3/d;进水BOD≤250mg/L;进水SS≤250mg/L;出水BOD≤20mg/L;出水中大肠菌≤3000个/;制作泥饼307kg/d。     

人类活动与气候变暖互助响应研究

本文从“温室效应”的实质,温室气体的“变暖潜能”入手,分析了人类活动与气候变暧互助响应的“蝶形效应”,提出了人类共同控制金球变暖的行动方略。     

Carbonyl compounds in dining areas, kitchens and exhaust streams in restaurants with varying cooking methods in Kaohsiung, Taiwan

Eighteen carbonyl species in C₁–C₁₀ were measured in the dining areas, kitchens and exhaust streams of six different restaurant types in Kaohsiung, southern Taiwan. Measured results in the dining areas show that Japanese barbecue (45.06 ppb) had the highest total carbonyl concentrations (sum of 18 compounds), followed by Chinese hotpot (38.21 ppb), Chinese stir-frying (8.99 ppb), Western fast-food (8.22 ppb), Chinese–Western mixed style (7.38 ppb), and Chinese buffet (3.08 ppb), due to their different arrangements for dining and cooking spaces and different cooking methods. On average, low carbon-containing species (C₁–C₄), e.g., formaldehyde, acetaldehyde, acetone and butyraldehyde were dominant and contributed 55.01%–94.52% of total carbonyls in the dining areas of all restaurants. Meanwhile, Chinese–Western mixed restaurants (45.48 ppb) had high total carbonyl concentrations in kitchens mainly because of its small kitchen and poor ventilation. However, high carbon-containing species (C₅–C₁₀) such as hexaldehyde, heptaldehyde and nonanaldehyde (16.62%–77.00% of total carbonyls) contributed comparatively with low carbon-containing compounds (23.01%–83.39% of total carbonyls) in kitchens. Furthermore, Chinese stir-frying (132.10 ppb), Japanese barbecue (125.62 ppb), Western fast-food (122.67 ppb), and Chinese buffet (119.96 ppb) were the four restaurant types with the highest total carbonyl concentrations in exhaust streams, indicating that stir-frying and grilling are inclined to produce polluted gases. Health risk assessments indicate that Chinese hotpot and Japanese barbecue exceeded the limits of cancer risk (10^− 6) and hazard index (= 1), mainly due to high concentrations of formaldehyde. The other four restaurants were below both limits.