Passive Samplers for NOx Monitoring: A Critical Review

Nitrogen oxide is an important gaseous air pollutant. It plays a major role in atmospheric chemistry, particularly in the formation of secondary air pollutants such as ozone, peroxyacyl nitrate (PAN), nitrate aerosols, and contributes to environmental acidification. A comprehensive assessment of NO₂ levels in the atmosphere is required for developing effective strategies for control of air pollution and improvement of air quality. Consequently, spatial NO₂ monitoring has become an important aspect of air quality assessment. Present NO₂ monitoring networks are mostly confined to urban areas, having a limited number of monitoring sites. Wide spatial NO₂ monitoring in India is constrained because of the limited availability of the monitoring equipment, such as continuous chemiluminesence monitors, high volume and handy samplers, which are expensive and need to be imported. Moreover, they require elaborate infrastructure, scientific personnel, technical support and uninterrupted power supply. In an effort to overcome the above shortcomings, passive samplers have been successfully used for large scale monitoring of NO₂ in the ambient environment.In recent years, passive samplers have been gaining increasing attention because they are simple, lightweight and cheap devices, which operate without any power source. Passive samplers have been found to be efficient, cost effective and free from the need for elaborate calibration and maintenance. Hence, they are ideally suited for developing a wide spatial network for NO₂ monitoring. This paper presents a comprehensive review including, historical development and critical assessment of validation studies along with comparison of both badge and tube type passive samplers. An attempt has been also made to highlight advantages and limitations, as well as discussion on the factors affecting the efficiency of passive samplers under field conditions.     

含氟烟气的净化与回收

含氟烟气是主要的大气污染物之一,本文就铝电解、磷肥工业产生的含氟烟气的一般治理方法进行了综述,各企业应因地制宜,选用技术先进、经济合理、操作简单、可有效控制污染的含氟烟气净化工艺.     

被动采样监测遂宁市NO2时空分布特征

采用被动扩散采样技术,在遂宁市辖区16km×16km网格区域内开展了为期1a的环境空气NO2监测,分析了不同时空内的NO2浓度变化趋势。研究表明：NO2浓度季节变化规律是：冬季〉春季〉秋季〉夏季;在全市各个区域中,浓度最高值出现在全市工业集中及车流量较大的区域（船山区）;受遂宁市污染源整体布局以及主导风向（西北风）的影响,全辖区范围内NO2呈现西北低、东南高的趋势。     

2008~2010年北京城区大气BTEX的浓度水平及其O3 生成潜势

苯、甲苯、乙苯及二甲苯是典型的人为排放有机物,不仅危害人体健康还参与对流层的光化学反应,生成O3和二次有机气溶胶.为认知北京大气中BTEX的浓度水平,评估其O3生成潜势,于2007年12月～2010年11月使用被动采样和化学分析相结合的方法对BTEX和O3浓度进行了连续3 a的同步观测.结果表明,北京城区大气BTEX中甲苯的浓度高达(8.7±3.1)μg·m-3,其次为苯、乙苯和间对二甲苯,浓度分别为(7.1±3.3)、(4.2±1.4)和(3.4±1.5)μg·m-3.BTEX总浓度在春、夏、秋和冬季的平均值分别为(16.8±1.4)、(24.7±2.8)、(25.9±4.9)和(26.8±12.1)μg·m-3,冬季苯的浓度全年最高,而夏季甲苯浓度高于冬季.采用最大增量反应活性方法计算了北京城区大气BTEX夏季O3生成潜势,发现间对二甲苯的贡献最大.北京2008、2009和2010年夏季BTEX的O3生成潜势分别为65.2、60.2和75.7μg·m-3,与O3实际浓度的年际变化趋势一致(同期浓度分别为80.5、65.0和101.9μg·m-3).机动车尾气和溶剂挥发是北京城区大气BTEX的主要来源,冬季苯的浓度可能受取暖燃煤的影响,夏季溶剂挥发对BTEX影响更大,并对O3的生成有一定贡献.     

Assessment of the Usefulness of Semipermeable Membrane Devices for Long-Term Watershed Monitoring in an Urban Slough System

Semipermeable membrane devices (SPMDs) were deployed at eight sites within the Buffalo Slough, near Portland, Oregon, to (1) measure the spatial and seasonal distribution of dissolved polycyclic aromatic hydrocarbon (PAH) and organochlorine (OC) compounds in the slough, (2) assess the usefulness of SPMDs as a tool for investigating and monitoring hydrophobic compounds throughout the Columbia Slough system, and (3) evaluate the utility of SPMDs as a tool for measuring the long-term effects of watershed improvement activities. Data from the SPMDs revealed clear spatial and seasonal differences in water quality within the slough and indicate that for hydrophobic compounds, this time-integrated passive-sampling technique is a useful tool for long-term watershed monitoring. In addition, the data suggest that a spiking rate of 2–5 μg/SPMD of permeability/performance reference compounds, including at least one compound that is not susceptible to photodegradation, may be optimum for the conditions encountered here.     

关于“二手烟”污染危害性的探讨

烟草危害是当今世界最严重的公共卫生问题之一。目前全球共有11亿吸烟者,烟草每年造成的死亡估计为1000万人,每10秒就有一人死于“香烟”危害。如何减轻“二手烟”危害,关系着烟民的自身健康及社会环境的可持续健康发展。“二手烟”实际上由两种烟雾构成：一种是吸烟者呼出的烟雾称为主流烟;另一种是香烟燃烧时所产生的烟雾称为分流烟。吸“二手烟”比原先外界所知道的还要危险一些,与吸烟者共同生活的女性患肺癌的几率比常人多出6倍。为了孩子们的成长、为了那些素不相识的不吸烟者健康、更为了吸烟者自已,我们奉劝吸烟者要少抽或不抽香烟。     

北京市民居室内气态多环芳烃呼吸暴露评价

采用被动采样装置采集并测定北京地区38个家庭采暖期和非采暖期室内空气中的7种气态多环芳烃(PAHs)的含量.结果表明,室内气态PAHs以2、3环组分为主,7种气态PAHs的总平均浓度为100 ng/m3左右.根据实测的PAHs浓度、不同年龄段人群室内平均停留时间及其相应的呼吸速率,计算得到室内成年人(包括老人)对7种气态PAHs的潜在总暴露速率在采暖期和非采暖期分别为66 ng/h和58 ng/h;而未成年人的潜在总暴露速率则分别为56 ng/h和50 ng/h.     

哈尔滨市大气气相中多环芳烃的研究

在哈尔滨地区8个采样点同时安装了PUF大气被动采样器,研究了该地区2007年春季(1月末~4月末)大气气相中多环芳烃的含量和分布特征.结果表明,PUF大气被动采样器主要采集了大气气相中三环和四环的多环芳烃,占总量的91.22%~96.37%,PAHs的浓度具有明显的功能区差异,依次为:市区(356.49 ng/d),郊区(162.65 ng/d),农村(278.35 ng/d),偏远地区(183.99 ng/d),市区大气中多环芳烃的浓度是农村的2倍,偏远地区的3倍.污染源是影响大气中多环芳烃含量高低的主要因素,通过特征分子含量比值法对该地区大气中多环芳烃的来源进行了初步研究,结果表明,哈尔滨地区城市大气中多环芳烃主要来自于燃煤,农村大气中的多环芳烃主要来自于农作物秸秆的燃烧.利用毒性当量因子法对该地区大气气相中多环芳烃的健康风险进行了评价,具有与浓度分布类似的功能区差异,表明市区和农村地区大气中PAHs对于人们的健康存在较大潜在威胁.通过安装平行采样器,PUF被动采样器具有很好的重现性,研究表明,可以用于城市尺度多个采样点大气中多环芳烃的同时研究.     

钝化金属深海环境电偶腐蚀性能研究

根据美国深海环境试验取得的数据和我国表层海水取得的数据,可知钛合金TA2与不锈钢SS316在海洋环境中无电偶腐蚀倾向,实际使用中SS316却出现了严重的电偶腐蚀。针对这一问题,在深海和模拟深海环境中对TA2和SS316的电偶腐蚀性能进行了研究,结果表明,静态下TA2和SS316无电偶腐蚀产生;当两种金属相互摩擦使SS316钝化膜破损时,产生电偶腐蚀,SS316为偶对中的阳极,会加速腐蚀。     

树皮在大气有机氯农药监测中应用的研究进展

有机氯农药（Organochlorine pesticides, OCPs）曾在全世界被大量使用,即使禁用多年,仍能在各种环境介质中被广泛检出,对生态环境和人体健康存在着潜在的威胁。因此OCPs的环境迁移和归趋一直是该领域的研究热点。树皮是一种天然的被动采样器,能够很好的反映出大气有机物长期的污染程度。本文简要论述了树皮作为被动采样器在大气污染物监测研究中应用的优势,并对OCPs在树皮中的残留浓度、特征及影响其富集的因素进行了探讨,最后特别针对具有手性的OCPs在树皮中的对映体选择性特征进行了评述。