Measuring OVOCs and VOCs by PTR-MS in an urban roadside microenvironment of Hong Kong: relative humidity and temperature dependence, and field intercomparisons
Measuring OVOCs and VOCs by PTR-MS in an urban roadside microenvironment of Hong Kong: relative humidity and temperature dependence, and field intercomparisons
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DOI：
10.5194/amt-9-5763-2016
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发表时间：
2016-12
影响因子：
3.8
通讯作者：
L. Cui;Zhou Zhang;Yu Huang;Shuncheng Lee;D. Blake;K. Ho;Bei Wang;Yuan Gao;Xinming Wang;P. Louie
中科院分区：
文献类型：
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作者：
L. Cui;Zhou Zhang;Yu Huang;Shuncheng Lee;D. Blake;K. Ho;Bei Wang;Yuan Gao;Xinming Wang;P. Louie
摘要。挥发性有机化合物（VOC）的控制是香港空气质素管理的重要课题，因为臭氧的形成通常受到VOC的限制。几种含氧挥发性有机化合物（OVOC）和VOC测量技术-即(1)离线2,4-二硝基苯肼（DNPH）药筒取样，然后进行高效液相色谱（HPLC）分析；(2)在线气相色谱（GC）火焰电离检测（FID）；(3)离线罐取样，随后采用气相色谱质谱检测（MSD）、FID和电子捕获检测（ECD）。质子转移反应-质谱（PTR-MS）技术首次应用于香港市区路边的挥发性有机化合物和挥发性有机化合物的测量。本研究探讨了环境相对湿度（RH）和温度(T)对PTR-MS测定甲醛的综合影响。对实验反应速率系数比、环境相对湿度和温度进行非线性表面模拟，发现Poly - 2-D回归（r = 0.97）是测量甲醛的最佳方法。在香港旺角（MK）进行了为期2年的实地采样活动，发现这种校正方法比直接通过进口样品的绝对湿度校正甲醛浓度更好。对于OVOC，甲醛、乙醛、丙酮和MEK在PTR-MS和DNPH-HPLC之间的斜率分别为1.00、1.10、0.76和0.88，相关系数分别为0.79、0.75、0.60和0.93。总的来说，PTR-MS和在线GC-FID对苯（斜率= 1.23,r = 0.95）、甲苯（斜率= 1.01,r = 0.96）和c2 -苯（斜率= 1.02,r = 0.96）的测定结果一致，因为苯和c2 -苯可能受到乙苯形成的碎片的影响。通过GC-MSD/FID/ECD将PTR-MS与离线罐测量结果进行比较，苯的斜率为1.05 (r = 0.62)，但PTR-MS对甲苯和c2苯的斜率较低，分别为0.78 （r = 0.96）和0.67 （r = 0.92）。总而言之，PTR-MS仪器适用于城市路边VOC和VOC的测量。
Abstract. Volatile organic compound (VOC) control is an important issue of air quality management in Hong Kong because ozone formation is generally VOC limited. Several oxygenated volatile organic compound (OVOC) and VOC measurement techniques – namely, (1) offline 2,4-dinitrophenylhydrazine (DNPH) cartridge sampling followed by high-performance liquid chromatography (HPLC) analysis; (2) online gas chromatography (GC) with flame ionization detection (FID); and (3) offline canister sampling followed by GC with mass spectrometer detection (MSD), FID, and electron capture detection (ECD) – were applied during this study. For the first time, the proton transfer reaction–mass spectrometry (PTR-MS) technique was also introduced to measured OVOCs and VOCs in an urban roadside area of Hong Kong. The integrated effect of ambient relative humidity (RH) and temperature (T) on formaldehyde measurements by PTR-MS was explored in this study. A Poly 2-D regression was found to be the best nonlinear surface simulation (r = 0.97) of the experimental reaction rate coefficient ratio, ambient RH, and T for formaldehyde measurement. This correction method was found to be better than correcting formaldehyde concentrations directly via the absolute humidity of inlet sample, based on a 2-year field sampling campaign at Mong Kok (MK) in Hong Kong. For OVOC species, formaldehyde, acetaldehyde, acetone, and MEK showed good agreements between PTR-MS and DNPH-HPLC with slopes of 1.00, 1.10, 0.76, and 0.88, respectively, and correlation coefficients of 0.79, 0.75, 0.60, and 0.93, respectively. Overall, fair agreements were found between PTR-MS and online GC-FID for benzene (slope = 1.23, r = 0.95), toluene (slope = 1.01, r = 0.96) and C2-benzenes (slope = 1.02, r = 0.96) after correcting benzene and C2-benzenes levels which could be affected by fragments formed from ethylbenzene. For the intercomparisons between PTR-MS and offline canister measurements by GC-MSD/FID/ECD, benzene showed good agreement, with a slope of 1.05 (r = 0.62), though PTR-MS had lower values for toluene and C2-benzenes with slopes of 0.78 (r = 0.96) and 0.67 (r = 0.92), respectively. All in all, the PTR-MS instrument is suitable for OVOC and VOC measurements in urban roadside areas.