Mukerjee Shaibal, Smith Luther A, Norris Gary A, Morandi Maria T, Gonzales Melissa, Noble Christopher A, Neas Lucas M, Ozkaynak A Halûk
U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA.
J Air Waste Manag Assoc. 2004 Mar;54(3):307-19. doi: 10.1080/10473289.2004.10470903.
This study evaluates the performance of Model 3300 Ogawa Passive Nitrogen Dioxide (NO2) Samplers and 3M 3520 Organic Vapor Monitors (OVMs) by comparing integrated passive sampling concentrations to averaged hourly NO2 and volatile organic compound (VOC) measurements at two sites in El Paso, TX. Sampling periods were three time intervals (3-day weekend, 4-day weekday, and 7-day weekly) for three consecutive weeks. OVM concentrations were corrected for ambient pressure to account for higher elevation. Precise results (< 5% relative standard deviation, RSD) were found for NO2 measurements from collocated Ogawa samplers. Reproducibility was lower from duplicate OVMs for BTEX (benzene, toluene, ethylbenzene, and xylene isomers) VOCs (> or = 77% RSD for 2-day samples) with better precision for longer sampling periods. Comparison of Ogawa NO2 samplers with chemiluminescence measurements averaged over the same time period suggested potential calibration problems with the chemiluminescence analyzer. For BTEX species, generally good agreement was obtained between OVMs and automated-gas chromatograph (auto-GC) measurements. The OVMs successfully tracked increasing levels of VOCs recorded by the auto-GCs. However, except for toluene, OVM BTEX measurements generally exceeded their continuous counterparts with a mean bias of 5-10%. Although interpretation of the study results was limited due to small sample sizes, diffusion barrier influences caused by shelters that housed OVMs and differences in sampling heights between OVMs and auto-GC inlet may explain the overestimation.
本研究通过比较在德克萨斯州埃尔帕索两个地点的综合被动采样浓度与每小时平均二氧化氮（NO₂）和挥发性有机化合物（VOC）测量值，评估了3300型小川被动式二氧化氮采样器和3M 3520有机蒸汽监测仪（OVM）的性能。采样期为连续三周的三个时间间隔（3天周末、4天工作日和7天每周）。对OVM浓度进行了环境压力校正，以考虑更高的海拔高度。从小川采样器并置处获得的NO₂测量结果具有精确性（相对标准偏差<5%，RSD）。对于苯系物（苯、甲苯、乙苯和二甲苯异构体）VOC，重复的OVM的重现性较低（2天样品的RSD≥77%），较长采样期的精度更高。将小川NO₂采样器与同一时间段内的化学发光测量平均值进行比较，表明化学发光分析仪存在潜在的校准问题。对于苯系物，OVM与自动气相色谱仪（auto-GC）测量结果总体上具有良好的一致性。OVM成功跟踪了auto-GC记录的VOC水平的上升。然而，除甲苯外，OVM的苯系物测量值通常超过其连续测量值，平均偏差为5-10%。尽管由于样本量小，研究结果的解释受到限制，但容纳OVM的遮蔽物造成的扩散屏障影响以及OVM与auto-GC进样口之间采样高度的差异可能解释了这种高估现象。
