Zhang Yu-Jie, Pang Xiao-Bing, Mu Yu-Jing
Research Center of Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Huan Jing Ke Xue. 2009 Apr 15;30(4):976-81.
Methacrolein (MACR) and methyl vinyl ketone (MVK), which are the characteristic products of isoprene photooxidation in the atmosphere, as well as formaldehyde, were determined during March to November of 2006 in the ambient air of Beijing city. Cartridges coated with 2, 4-dinitrophenylhenylhydrazine (DNPH) were used to collect those carbonyls in ambient air and a high pressure liquid chromatography (HPLC) was used for quantification. Distinct amounts of MACR and MVK were detected during vegetable growing seasons from April to October with ambient levels in ranges of 0.11 x 10(-9) - 0.67 x 10(-9) and 0.19 x 10(-9) - 1.36 x 10(-9), respectively, with their maximal concentrations appearing in August. MACR and MVK were measured under the detecting limit in March and November, which may be ascribed to low isoprene emission from the broadleaf trees without leaves during two months. According to the stoichiometric coefficients among MVK, MACR, isoprene and formaldehyde, the concentrations of the reacted isoprene due to photo-oxidation can be calculated derived from the concentrations of the measured MVK and MACR. Then, the monthly (April to October) average concentrations of formaldehyde produced by the photo-oxidation of reacted isoprene were roughly estimated to be in the range of 0.35 x 10(-9) - 2.5 x 10(-9), which accounted for 4.6%-11.5% of total atmospheric formaldehyde. During the period with active atmospheric photo-oxidation (June to August), the contribution of biogenic isoprene to formaldehyde was predominant. Therefore, the biogenic isoprene is an important source to local photo-oxidant formation in Beijing and should be considered of.
甲基丙烯醛（MACR）和甲基乙烯基酮（MVK）是大气中异戊二烯光氧化的特征产物，2006年3月至11月期间在北京城区环境空气中对它们以及甲醛进行了测定。用涂有2,4 - 二硝基苯肼（DNPH）的采样管采集环境空气中的这些羰基化合物，并用高压液相色谱（HPLC）进行定量分析。在4月至10月的蔬菜生长季节检测到了不同量的MACR和MVK，其环境浓度范围分别为0.11×10⁻⁹ - 0.67×10⁻⁹和0.19×10⁻⁹ - 1.36×10⁻⁹，其最大浓度出现在8月。3月和11月MACR和MVK的测量值低于检测限，这可能归因于这两个月阔叶树无叶，异戊二烯排放量较低。根据MVK、MACR、异戊二烯和甲醛之间的化学计量系数，可以从测得的MVK和MACR浓度计算得出因光氧化反应的异戊二烯浓度。然后，估算出4月至10月期间因反应异戊二烯光氧化产生的甲醛月平均浓度大致在0.35×10⁻⁹ - 2.5×10⁻⁹范围内，占大气中总甲醛的4.6% - 11.5%。在大气光氧化活跃期（6月至8月），生物源异戊二烯对甲醛的贡献占主导。因此，生物源异戊二烯是北京本地光氧化剂形成的重要来源，应予以考虑。
