Isoprene in poplar emissions: effects on new particle formation and OH concentrations
Isoprene in poplar emissions: effects on new particle formation and OH concentrations
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DOI：
10.5194/acp-12-1021-2012
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发表时间：
2011-08
影响因子：
6.3
通讯作者：
A. Kiendler‐Scharr;S. Andres;M. Bachner;K. Behnke;S. Broch;A. Hofzumahaus;F. Holland;E. Kleist;T. Mentel;F. Rubach;M. Springer;B. Steitz;R. Tillmann;A. Wahner;J. Schnitzler;J. Wildt
中科院分区：
文献类型：
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作者：
A. Kiendler‐Scharr;S. Andres;M. Bachner;K. Behnke;S. Broch;A. Hofzumahaus;F. Holland;E. Kleist;T. Mentel;F. Rubach;M. Springer;B. Steitz;R. Tillmann;A. Wahner;J. Schnitzler;J. Wildt
抽象的。利用异戊二烯排放潜力修饰的转基因灰白杨在胁迫下产生的挥发性有机物（VOC）排放，研究了光化学二次有机气溶胶（SOA）的形成。在白杨中，急性臭氧胁迫诱导排放的挥发性有机物占主导地位的倍半萜和芳香族挥发性有机物。非转基因对照（野生型WT）中异戊二烯的组成性光依赖性排放范围为66 nmol m −2 s −1，异戊二烯排放抑制植物（品系RA 22）中的范围接近零（−2 s −1）。在我们的实验中观察到高达3600 cm −3 s −1的成核速率。与不含异戊二烯的VOC混合物相比，在异戊二烯的存在下，抑制了新颗粒的形成。与其他植物释放的异戊二烯/单萜体系相比，异戊二烯对胁迫白杨释放的VOC混合物的成核抑制效果较差。这是解释所观察到的高效率的新的颗粒形成的排放压力白杨。在反应室中OH的直接测量揭示了在异戊二烯存在下OH的稳态浓度比在不存在异戊二烯的情况下低，支持异戊二烯对成核的抑制作用与自由基化学有关的假设。为了测试异戊二烯是否有助于SOA质量的形成，将全氘代异戊二烯（C5 D8）添加到无异戊二烯白杨突变体的胁迫诱导的排放曲线中。质谱分析表明，尽管异戊二烯诱导的颗粒形成的抑制，氘代异戊二烯馏分纳入SOA。观察到异戊二烯的质量分数产率为2.3%。因此，由于土地利用和气候变化，未来排放量的变化可能会影响气相氧化能力和新颗粒数的形成。
Abstract. Stress-induced volatile organic compound (VOC) emissions from transgenic Grey poplar modified in isoprene emission potential were used for the investigation of photochemical secondary organic aerosol (SOA) formation. In poplar, acute ozone stress induces the emission of a wide array of VOCs dominated by sesquiterpenes and aromatic VOCs. Constitutive light-dependent emission of isoprene ranged between 66 nmol m −2 s −1 in non-transgenic controls (wild type WT) and nearly zero ( −2 s −1 ) in isoprene emission-repressed plants (line RA22), respectively. Nucleation rates of up to 3600 cm −3 s −1 were observed in our experiments. In the presence of isoprene new particle formation was suppressed compared to non-isoprene containing VOC mixtures. Compared to isoprene/monoterpene systems emitted from other plants the suppression of nucleation by isoprene was less effective for the VOC mixture emitted from stressed poplar. This is explained by the observed high efficiency of new particle formation for emissions from stressed poplar. Direct measurements of OH in the reaction chamber revealed that the steady state concentration of OH is lower in the presence of isoprene than in the absence of isoprene, supporting the hypothesis that isoprenes' suppressing effect on nucleation is related to radical chemistry. In order to test whether isoprene contributes to SOA mass formation, fully deuterated isoprene (C 5 D 8 ) was added to the stress-induced emission profile of an isoprene free poplar mutant. Mass spectral analysis showed that, despite the isoprene-induced suppression of particle formation, fractions of deuterated isoprene were incorporated into the SOA. A fractional mass yield of 2.3% of isoprene was observed. Future emission changes due to land use and climate change may therefore affect both gas phase oxidation capacity and new particle number formation.