Abstract：
Over the last decade, the French ATR-42 research aircraft explored contrasting polluted plumes in the Paris megacity, the North-West Mediterranean Basin (WMB) and South West Africa (SWA) in the framework of the MEGAPOLI, ChArMEx/SAFMED and DACCIWA international projects, respectively. Major VOCs were measured by a high-sensitivity airborne Quadrupole Proton Transfer Reaction Mass Spectrometer (Q-PTR-MS), showing a robust and consistent response. Regardless of the location, the air mass composition is dominated by oxygenated VOC (OVOC: methanol, formaldehyde, acetaldehyde, acetone and isoprene oxidation products), which explain 70 % of the total VOC burden measured by the Q-PTR-MS. The distribution between OVOC, anthropogenic AVOC and biogenic BVOC is consistent between the three regions. The calculated OH loss rates (12 s-1) and ozone-forming potential (1200 OFP-relative ppb) are three times higher in the SWA plumes. These values are consistent with the calculated and measured reactivities at the ground. The reactivity of the plumes is by far dominated by biogenic BVOC. The chemical processing of VOC was examined by establishing various metrics linking Δ[O/VOC] (VOC or oxygenated VOC), plume dilution and the time processing of the plume (cumulative OH exposure Δt[OH] and the linear decay of primary AVOC and the production/decay of secondary OVOC). As expected, ∆[Ox]/∆[CO] increases with Δt[OH], with significant R2 (0.58 to 0.93). AVOC (aromatics) usually show a decay rate between -0.5 and -3.2 pptAVOC ppbCO-1 per hour, while OVOC either show an increase (secondary production) or a decrease. The production rate is by far the strongest, up to 18 pptOVOC ppbCO-1 per hour (acetaldehyde) during the eastern flight 33 in Paris. Our results set a benchmark for future photochemical studies to compare with. While the anthropogenic origin of some BVOC (terpenoids) and interferences are not excluded, it also emphasizes the importance of the VOC biogenic fraction in anthropogenically influenced environments, which is expected to increase in a warming climate.
摘要：
在过去的十年里，法国ATR-42研究飞机在巴黎大城市探索了对比污染的羽流，在MEGAPOLI框架内的西北地中海盆地（WMB）和西南非洲（SWA），ChArMEx/SAFMED和DACCIWA国际项目，分别。主要的挥发性有机化合物通过高灵敏度的机载四极质子转移反应质谱仪（Q-PTR-MS）进行测量，显示出稳健和一致的反应。不管在哪里,空气质量成分主要由含氧VOC(OVOC：甲醇，甲醛,乙醛,丙酮和异戊二烯氧化产物)，这解释了Q-PTR-MS测得的总VOC负荷的70％。OVOC之间的分布，人为AVC和生物源BVOC在三个地区之间是一致的。在SWA羽流中，计算出的OH损失率（12s-1）和臭氧形成潜力（1200OFP-相对ppb）高三倍。这些值与在地面计算和测量的反应性一致。羽流的反应性到目前为止由生物源BVOC主导。通过建立连接Δ[O/VOC]（VOC或含氧VOC）的各种指标来检查VOC的化学处理，羽流稀释和羽流的时间处理（累积OH暴露Δt[OH]和初级AVOC的线性衰减和次级OVOC的产生/衰减）。不出所料,Δ[Ox]/Δ[CO]随Δt[OH]增加，具有显著的R2(0.58至0.93)。AVOC（芳烃）通常显示每小时-0.5和-3.2pptAVOCppbCO-1之间的衰变速率，而OVOC要么显示增加(二次生产)，要么显示减少。生产率是迄今为止最强的，在巴黎东部航班33期间，每小时高达18pptOVOCppbCO-1（乙醛）。我们的结果为未来的光化学研究提供了基准。虽然不排除某些BVOC（萜类化合物）的人为起源和干扰，它还强调了VOC生物成分在人为影响的环境中的重要性，在气候变暖的情况下，预计会增加。
