Chemical characterization of the boundary layer outflow of air pollution to Hong Kong during February–April 2001
Chemical characterization of the boundary layer outflow of air pollution to Hong Kong during February–April 2001
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DOI：
10.1029/2002jd003272
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发表时间：
2003-10
影响因子：
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通讯作者：
Tao Wang;A. Ding;D. Blake;W. Zahorowski;C. N. Poon;Y. Li
中科院分区：
文献类型：
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作者：
Tao Wang;A. Ding;D. Blake;W. Zahorowski;C. N. Poon;Y. Li
[1]作为与TRACE-P和ACE-Asia在2001年春季密集合作的一项努力，在香港东南部一个相对偏远的沿海站点（鹤咀）测量了痕量气体和气溶胶。测量方案的主要目的是提供东亚亚热带地区的连续地面数据，并描述早春期间低层大气中大陆污染物向南流出的特征。在本文中，我们提出了臭氧，CO，NO，NOy，SO2，222氡，甲烷和C2-C8非甲烷烃（NMHCs），C1-C2卤代烃，和C1-C5烷基硝酸酯测量2001年2月19日和4月30日之间获得的结果。O3、CO、SO2和NOy的平均混合比分别为45 ppbv、404 ppbv、1.8 ppbv和10.4 ppbv。两种主要的非金属碳氢化合物是乙烷（平均值：2368 pptv）和乙炔（平均值：1402 pptv），其次是丙烷（814 pptv）、甲苯（540 pptv）、苯（492 pptv）、乙烯（498 pptv）和正丁烷（326 pptv）。最丰富的卤代烃是CH 3Cl（平均值：821 pptv），而2-BuONO 2和i-PrONO 2是两个主要的硝酸烷基酯物种，平均混合比分别为20 pptv和19 pptv。微量气体的水平强烈影响的大陆空气质量的外流开始通过冷锋。根据222 Rn水平和风向，将数据分为四个气团组，分别代表新鲜的大陆外流、沿海、扰动的海洋和当地城市空气。臭氧和CO呈中度正相关（r2 = 0.4）的海洋空气组，其特点是低222 Rn和CO水平，但它们在其他气团组相关性较差。SO2和NOy之间具有良好的相关性（r2> 0.6），但与CO之间的相关性较差，表明它们的排放源和/或去除过程存在差异。CO与乙炔和苯有很强的相关性（r2> 0.85），与其它几种非金属烃也有很好的相关性.此外，CO与生物质燃烧示踪剂（CH 3Cl）和城市/工业示踪剂（C2Cl 4），表明城市和生物质燃烧源的混合污染的影响中度相关。研究了CO、SO2和NOy与乙炔/ CO和丙烷/乙烷的关系。将2001年的数据与1994年同期在PEM-West B期间获得的结果进行了比较。2001年春季的平均臭氧水平比PEM-West B期间高得多。SO2在TRACE-P期间也有较高的浓度，而CO和NOy在两个运动期间相当。在排放变化和气象变化的背景下讨论了观测到的差异。虽然很难对这两个因素的影响程度得出明确的结论，但似乎更清晰的天空和更干燥的条件可能是TRACE-P期间臭氧浓度较高的原因。索引术语：0345大气组成与结构：污染-城市和区域（0305）; 0365大气组成与结构：对流层-组成与化学; 0368大气组成与结构：对流层-成分输送与化学;
[1] As a cooperative effort with the TRACE-P and ACE-Asia intensive in the spring of 2001, trace gases and aerosols were measured at a relatively remote coastal site (Hok Tsui) in southeastern Hong Kong. The main objective of the measurement program was to provide continuous ground-based data in the subtropical region of eastern Asia and to characterize the southward outflow of continental pollution that prevails in the lower atmosphere during early spring. In this paper, we present the results for ozone, CO, NO, NOy ,S O2, 222 Radon, methane and C2–C8 nonmethane hydrocarbons (NMHCs), C1–C2 halocarbons, and C1–C5 alkyl nitrate measurements obtained between 19 February and 30 April 2001. The average mixing ratios of O3, CO, SO2, and NOy were 45 ppbv, 404 ppbv, 1.8 ppbv, and 10.4 ppbv, respectively. The two dominant NMHCs were ethane (mean: 2368 pptv) and ethyne (mean: 1402 pptv), followed by propane (814 pptv), toluene (540 pptv), benzene (492 pptv), ethene (498 pptv), and n-butane (326 pptv). The most abundant halocarbon was CH3Cl (mean: 821 pptv), while 2-BuONO2 and i-PrONO2 were the two dominant alkyl nitrates species with a mean mixing ratio of 20 pptv and 19 pptv, respectively. The levels of trace gases were strongly influenced by the outflow of continental air masses initiated by the passage of cold fronts. The data are segregated into four air mass groups according to the levels of 222 Rn and wind direction, representing fresh continental outflow, coastal, perturbed maritime, and local urban air. Ozone and CO showed a moderate positive correlation (r 2 = 0.4) in the marine air group, characterized by low 222 Rn and CO levels, but they were poorly correlated in the other air mass groups. SO2 and NOy exhibited good correlations (r 2 > 0.6) with each other but were poorly correlated with CO, indicating differences in their emission sources and/or removal processes. CO very strongly correlated with ethyne and benzene (r 2 > 0.85) and also showed good correlations with several other NMHCs. Moreover, CO correlated moderately with a biomass burning tracer (CH3Cl) and an urban/industrial tracer (C2Cl4) indicating the impact of mixed pollution from urban and biomass burning sources. The relationship of CO, SO2, and NOy with the indicator of atmospheric processing, ethyne/ CO and propane/ethane, were also examined. The 2001 data were compared to the results obtained in the same period in 1994 during PEM-West B. The mean ozone level in the spring of 2001 was much higher than during PEM-West B. SO2 also had higher concentrations during TRACE-P, while CO and NOy were comparable during the two campaigns. The observed difference has been discussed in the context of emission changes and variations in meteorology. Although it is difficult to draw definitive conclusions about the extent of the influence of these two factors, it appears that clearer skies and drier conditions may have been responsible for the higher ozone concentrations during the TRACE-P period. INDEX TERMS: 0345 Atmospheric Composition and Structure: Pollution—urban and regional (0305); 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry; 0368 Atmospheric Composition and Structure: Troposphere—constituent transport and chemistry;