Intercomparison of four different in-situ techniques for ambient formaldehyde measurements in urban air
Intercomparison of four different in-situ techniques for ambient formaldehyde measurements in urban air
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DOI：
10.5194/acp-5-2881-2005
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发表时间：
2005-11-02
影响因子：
6.3
通讯作者：
Volkamer, R
中科院分区：
文献类型：
--
作者：
Hak, C;Pundt, I;Volkamer, R
目前使用的几种原位技术测量大气甲醛（CH 2 O）的相互比较的结果。测量是在布雷索进行的，这是米兰（意大利）周边的一个城市，是FORMAT-I实地活动的一部分。八个仪器采用了六个独立的研究小组，使用四种不同的技术：差分光学吸收光谱（DOAS），傅里叶变换红外（FTIR）干涉，荧光Hantzsch反应技术（五个仪器）和色谱技术，采用C18-DNPH盒（2，4-二硝基苯肼）。光学技术采用了白色型多次反射系统，以避免空间CH 2 O梯度，并确保所有仪器对几乎相同的空气质量进行采样。2002年7月23日至31日期间，观测到高达13 ppbv的CH 2 O。浓度远高于所有仪器的检测限。发现用DOAS、FTIR和Hantzsch仪器测定的甲醛浓度在+/-11%范围内一致，除了一个Hantzsch仪器，其给出了系统性的较高值。DNPH两小时积分样品产生的浓度比同一时间段内连续测量仪器的平均数据低25%。DOAS和Hantzsch方法之间的一致性优于以前在环境空气中的相互比较，回归线的斜率没有显着不同。单个Hantzsch仪器之间的差异可能部分归因于所使用的校准标准。讨论了这些方法可能存在的系统误差。
Results from an intercomparison of several currently used in-situ techniques for the measurement of atmospheric formaldehyde (CH2O) are presented. The measurements were carried out at Bresso, an urban site in the periphery of Milan ( Italy) as part of the FORMAT-I field campaign. Eight instruments were employed by six independent research groups using four different techniques: Differential Optical Absorption Spectroscopy (DOAS), Fourier Transform Infra Red ( FTIR) interferometry, the fluorimetric Hantzsch reaction technique ( five instruments) and a chromatographic technique employing C18-DNPH-cartridges (2,4-dinitrophenylhydrazine). White type multi-reflection systems were employed for the optical techniques in order to avoid spatial CH2O gradients and ensure the sampling of nearly the same air mass by all instruments. Between 23 and 31 July 2002, up to 13 ppbv of CH2O were observed. The concentrations lay well above the detection limits of all instruments. The formaldehyde concentrations determined with DOAS, FTIR and the Hantzsch instruments were found to agree within +/- 11%, with the exception of one Hantzsch instrument, which gave systematically higher values. The two hour integrated samples by DNPH yielded up to 25% lower concentrations than the data of the continuously measuring instruments averaged over the same time period. The consistency between the DOAS and the Hantzsch method was better than during previous intercomparisons in ambient air with slopes of the regression line not significantly differing from one. The differences between the individual Hantzsch instruments could be attributed in part to the calibration standards used. Possible systematic errors of the methods are discussed.