Clouds containing supercooled water are important for both climate and weather, but our knowledge of which aerosol particle types nucleate ice in these clouds is far from complete. Combustion aerosols have strong anthropogenic sources, and if these aerosol types were to nucleate ice in clouds, they might exert a climate forcing. Here, we quantified the atmospheric ice‐nucleating particle (INP) concentrations during the United Kingdom's annual Bonfire Night celebrations, which are characterized by large amounts of combustion aerosol from bonfires and fireworks. We used three immersion mode techniques covering more than 6 orders of magnitude in INP concentration over the temperature range from −10°C to homogeneous freezing. We found no observable systematic change in the INP concentration on three separate nights, despite more than a factor of 10 increase in aerosol number concentrations, up to a factor of 10 increase in PM₁₀ concentration, and more than a factor of 100 increase in black carbon (BC) mass concentration relative to pre‐event levels. This implies that BC and other combustion aerosol such as ash did not compete with the INPs present in the background air. Furthermore, the upper limit of the ice‐active site surface density, n_s(T), of BC generated in these events was shown to be consistent with several other recent laboratory studies, showing a very low ice‐nucleating activity of BC. We conclude that combustion aerosol particles similar to those emitted on Bonfire Night are at most of secondary importance for the INP population relevant for mixed‐phase clouds in typical midlatitude terrestrial locations.

中文翻译：

---

一次重大的燃烧气溶胶事件对大气中的冰核颗粒种群的影响可忽略不计

含有过冷水的云对气候和天气都非常重要，但是我们对哪种气溶胶颗粒使这些云中的冰成核的了解还远远不够。燃烧气溶胶具有很强的人为来源，如果这些气溶胶类型使云层中的冰成核，它们可能会施加气候强迫作用。在这里，我们量化了英国每年的篝火之夜庆祝活动期间大气中冰核颗粒（INP）的浓度，其特征是篝火和烟花产生大量燃烧气溶胶。我们使用了三种浸没模式技术，在从-10°C到均匀冷冻的温度范围内，INP浓度超过6个数量级。我们发现在三个单独的晚上，INP浓度没有明显的系统变化，相对于事前水平，黑碳（BC）质量浓度为₁₀浓度，增加了100倍以上。这意味着BC和其他燃烧气溶胶（例如灰烬）不会与背景空气中存在的INP竞争。此外，冰活性部位表面密度的上限，Ñ_小号（Ť），在这些事件中产生的BC的被证明是与其他几个最近的实验室研究一致，表明BC的非常低的冰成核活性。我们得出的结论是，对于典型中纬度陆地位置与混合相云有关的INP种群而言，与篝火之夜类似的燃烧气溶胶颗粒至多重要。