Abstract. Aerosol particles form in the atmosphere by clustering of certain atmospheric vapors. After growing to larger particles by condensation of low volatile gases, they can affect the Earth’s climate directly by scattering light and indirectly by acting as cloud condensation nuclei. Observations of low-volatility aerosol precursor gases have been reported around the world but longer-term measurement series and any Arctic data sets showing seasonal variation are close to non-existent. In here, we present ~7 months of aerosol precursor gas measurements performed with the nitrate based chemical ionization mass spectrometer (CI-APi-TOF). We deployed our measurements ~150 km North of the Arctic Circle at the continental Finnish sub-Arctic field station, SMEAR I, located in Värriö strict nature reserve. We report concentration measurements of the most common new particle formation related compounds; sulfuric acid (SA), methane sulfonic acid (MSA), iodic acid (IA) and a total concentration of highly oxygenated organic compounds (HOMs). At this remote measurement site, SA is originated both from anthropogenic and biological sources and has a clear diurnal cycle but no significant seasonal variation. MSA shows a more distinct seasonal cycle with concentrations peaking in the summer. Of the measured compounds, iodic acid concentrations are the most stable throughout the measurement period, except in April, when the concentration of IA is significantly higher than during the rest of the year. Otherwise, IA has almost identical daily maximum concentrations in spring, summer and autumn, and on new particle formation event or non-event days. HOMs are abundant during the summer months and low in winter months. Due to the low winter concentrations and their high correlation with ambient air temperature, we suggest that most of HOMs are products of biogenic emissions, most probably monoterpene oxidation products. New particle formation events at SMEAR I happen under relatively low temperatures with a fast temperature rise in the morning followed by decreasing relative humidity during the day. The ozone concentrations are on average ~10 ppbv higher on NPF days than non-event days. During NPF days, we have on average higher SA concentration peaking at noon, higher MSA concentrations in the afternoon and slightly higher IA concentration than during non-event days. All together, these are the first long term measurements of aerosol forming vapors from the SMEAR I in the sub-arctic region, and the results help us to understand atmospheric chemical processes and aerosol formation in the rapidly changing Arctic.

中文翻译：

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测量报告：对芬兰亚北极北方森林中气溶胶前体浓度的长期测量

摘要。气溶胶颗粒通过聚集某些大气蒸气在大气中形成。通过低挥发性气体的凝结成长为更大的颗粒后，它们可以通过散射光直接影响地球气候，并通过充当云凝结核间接影响地球气候。世界各地都报告了对低挥发性气溶胶前体气体的观察，但长期测量系列和任何显示季节性变化的北极数据集几乎不存在。在这里，我们展示了使用基于硝酸盐的化学电离质谱仪 (CI-APi-TOF) 进行的大约 7 个月的气溶胶前体气体测量。我们在位于 Värriö strict 自然保护区的芬兰大陆亚北极野外站 SMEAR I 部署了我们的测量结果，在北极圈以北约 150 公里处。我们报告了最常见的新颗粒形成相关化合物的浓度测量值；硫酸 (SA)、甲磺酸 (MSA)、碘酸 (IA) 和高含氧有机化合物 (HOM) 的总浓度。在该遥测点，SA 来源于人为源和生物源，具有明显的昼夜循环，但没有明显的季节变化。MSA 显示出更明显的季节性周期，浓度在夏季达到峰值。在测量的化合物中，碘酸浓度在整个测量期间是最稳定的，除了 4 月份，IA 的浓度显着高于一年中的其余时间。否则，IA 在春季、夏季和秋季以及新粒子形成事件或非事件日具有几乎相同的每日最大浓度。HOM 在夏季月份丰富，在冬季月份较低。由于冬季浓度低且与环境气温高度相关，我们认为大多数 HOM 是生物排放的产物，最有可能是单萜氧化产物。SMEAR I 的新粒子形成事件发生在相对较低的温度下，早上温度快速上升，然后白天相对湿度下降。NPF 日的臭氧浓度平均比非事件日高约 10 ppbv。在 NPF 期间，我们的平均 SA 浓度在中午达到峰值，MSA 浓度在下午更高，IA 浓度比非事件日略高。总之，这些是对亚北极地区 SMEAR I 气溶胶形成蒸汽的首次长期测量，