Light non-methane hydrocarbons at two sites in the Indo-Gangetic Plain.
Light non-methane hydrocarbons at two sites in the Indo-Gangetic Plain.
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印度恒河平原两个地点的轻质非甲烷碳氢化合物。
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发表时间：
2012
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通讯作者：
C. Mallik
中科院分区：
文献类型：
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作者：
S. Lal;L. Sahu;S. Venkataramani;C. Mallik
2004年12月，在印度印度恒河平原（IGP）的希萨尔和坎普尔，对轻（C（2）-C（5））非甲烷烃（NMHCs）以及臭氧（O（3））、氮氧化物（NO（x））、一氧化碳（CO）和甲烷（CH（4））进行了沿着测量。在中午和晚上的空气采样提供了一个机会，研究排放的特点和变化，在这段时间内在这些网站。由于光化学形成，O（3）的混合比在中午时间较高，而前体气体的水平在晴朗的天空中的傍晚时间显示出较高的值。在雾天没有这样的变化。雾天观测到的O（3）混合比较低，可能是由于稳定的行星边界层的存在导致太阳通量减少和表面沉积导致光化学形成速率较慢。丙烯和乙烯由于与OH自由基反应较快，显示出最高的昼夜比。不同种类的测量气体之间的相关性表明，生物质和生物燃料燃烧以及化石燃料燃烧的排放量的贡献。虽然与O（3）定性相关，但已计算了NMHCs的丙烯（丙烯）当量，以研究其在O（3）光化学中的作用，并与印度西部城市阿赫梅达巴德的数据进行了比较。对观测数据进行分析得出的重要结果是，虽然这些非甲烷碳氢化合物的总量在希萨尔最少，在阿赫梅达巴德最高，但丙烯当量总量在希萨尔最高，在阿赫梅达巴德最低。此外，IGP中的这两个站点显示出丙烯和乙烯的显著贡献，几乎为72- 77%，而在阿赫梅达巴德这两种气体的贡献仅为约47%。O（3）的表面水平混合比可以被视为在IGP上的区域尺度上的空气质量的化学表征的代表，因为O（3）的一个月的趋势显示出显着的相似性相比，在两个站点的前体的趋势。
Measurements of light (C(2)-C(5)) non-methane hydrocarbons (NMHCs) were made along with ozone (O(3)), oxides of nitrogen (NO(x)), carbon monoxide (CO) and methane (CH(4)) at Hissar and Kanpur in the Indo-Gangetic Plain (IGP) in India during the month of December, 2004. Air samplings during noon and evening hours provided an opportunity to study the emission characteristics and changes during this period at these sites. The mixing ratio of O(3) was higher during noon hours due to photochemical formation, while the levels of precursor gases showed elevated values during the evening hours on a clear sky day. On foggy days there is no such variation. The lower mixing ratios of O(3) observed on foggy days could be due to the slower rate of photochemical formation caused by a reduction in solar flux and surface deposition caused by the presence of a stable planetary boundary layer. Propene and ethene show the highest evening to noon ratio due to their faster reactivities with OH radicals. Correlations among different species of the measured gases indicate contributions of emissions from biomass and biofuel burning as well as fossil fuel combustion. Although qualitatively in relation to O(3), the propylene (propene) equivalents of NMHCs have been calculated to investigate their roles in O(3) photochemistry and compared with the data from Ahmedabad, an urban site in western India. The important result, which has emerged from the analysis of the observed data, is that while the total amount of these NMHCs is least at Hissar and highest at Ahmedabad, the total propylene-equivalent is highest at Hissar and lowest at Ahmedabad. Further, these two sites in the IGP show significant contributions, almost 72-77%, by propene and ethene while the contribution by these two gases at Ahmedabad is only about 47%. The surface level mixing ratios of O(3) could be treated as representative for the chemical characterization of air mass at a regional scale over the IGP as the month long trends of O(3) show significant similarity compared to the trends in precursors at the two sites.