Elemental carbon (EC) is a major light‐absorbing component of atmospheric aerosol particles. Here, we report the seasonal variation in EC concentrations and sources in airborne particulate matter (PM) and snow at Alert, Canada, from March 2014 to June 2015. We isolated the EC fraction with the EnCan‐Total‐900 (ECT9) protocol and quantified its stable carbon isotope composition (δ¹³C) and radiocarbon content (∆¹⁴C) to apportion EC into contributions from fossil fuel combustion and biomass burning (wildfires and biofuel combustion). Ten‐day backward trajectories show EC aerosols reaching Alert by traveling over the Arctic Ocean from the Russian Arctic during winter and from North America (>40°N) during summer. EC concentrations range from 1.8–135.3 ng C m⁻³ air (1.9–41.2% of total carbon [TC], n = 48), with lowest values in summer (1.8–44.5 ng C m⁻³ air, n = 9). EC in PM (Δ¹⁴C = ‐532 ± 114‰ [ave. ± SD, n = 20]) and snow (−257 ± 131‰, n = 7) was depleted in ¹⁴C relative to current ambient CO₂ year‐round. EC in PM mainly originated from liquid and solid fossil fuels from fall to spring (47–70% fossil), but had greater contributions from biomass burning in summer (48–80% modern carbon). EC in snow was mostly from biomass burning (53–88%). Our data show that biomass burning EC is preferentially incorporated into snow because of scavenging processes within the Arctic atmosphere or long‐range transport in storm systems. This work provides a comprehensive view of EC particles captured in the High Arctic through wet and dry deposition and demonstrates that surface stations monitoring EC in PM might underestimate biomass burning and transport.

中文翻译：

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加拿大Alert的空气中颗粒物和雪中基于元素同位素的碳同位素分配的季节性周期

元素碳（EC）是大气气溶胶颗粒的主要光吸收成分。在这里，我们报告了2014年3月至2015年6月加拿大预警中心的空气中颗粒物（PM）和雪中EC浓度和来源的季节性变化。我们使用EnCan‐Total‐900（ECT9）方案分离了EC组分并进行了定量其稳定的碳同位素组成（δ ¹³ C）和放射性碳含量（δ ¹⁴ C）分摊到EC从化石燃料燃烧和生物质燃烧（野火和生物燃料燃烧）的贡献。向后10天的轨迹显示，EC气溶胶在冬季从俄罗斯北极越过北冰洋，在夏季从北美（> 40°N）越过北冰洋到达警报。EC浓度范围为1.8-135.3纳克C M ^-3空气（总碳（TC）的1.9-41.2％，N = 48），在夏季最低值（1.8-44.5纳克C M ^-3空气中，n = 9）。EC在PM（Δ ¹⁴ C = -532±114‰（平均±SD，N = 20））和雪（-257±131‰，N = 7）的混合物在贫¹⁴ C相对于当前环境CO ₂常年。PM中的EC主要来自秋季至春季的液态和固态化石燃料（化石占47-70％），但夏季燃烧生物质的贡献更大（占现代碳的48-80％）。雪中​​的EC主要来自生物质燃烧（53-88％）。我们的数据表明，由于北极大气中的清除过程或风暴系统中的远距离运输，生物质燃烧EC优先纳入雪中。这项工作提供了通过湿式和干式沉积在高北极地区捕获的EC颗粒的全面视图，并表明监测PM中EC的地面站可能低估了生物质的燃烧和运输。