Abstract This study evaluates the error that is introduced in quantifying observed aerosol mixing states due to a limited particle sample size. We used the particle-resolved model PartMC-MOSAIC to generate a scenario library that encompasses a large number of reference particle populations with a wide range of mixing states quantified by the mixing-state index χ. We stochastically sub-sampled these particle populations using sample sizes of 10 to 10,000 particles and recalculated χ based on the sub-samples. The finite sample size led to a consistent overestimation of χ, with the 95% confidence intervals ranging from −70 to 30 percentage points for sample sizes of 10 particles, and decreasing to ±10 percentage points for sample sizes of 10,000 particles. These findings were experimentally confirmed with single-particle measurements from the Pittsburgh area using a soot-particle aerosol mass spectrometer. Copyright © 2020 American Association for Aerosol Research

中文翻译：

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基于有限粒子样本量量化气溶胶混合状态指数中的误差

摘要 本研究评估了由于粒子样本大小有限而在量化观察到的气溶胶混合状态时引入的误差。我们使用粒子解析模型 PartMC-MOSAIC 来生成一个场景库，该库包含大量参考粒子群，其混合状态范围很广，由混合状态指数 χ 量化。我们使用 10 到 10,000 个粒子的样本大小对这些粒子群进行随机子采样，并根据子样本重新计算 χ。有限的样本量导致 χ 的一致高估，10 个粒子的样本量的 95% 置信区间范围为 -70 到 30 个百分点，而 10,000 个粒子的样本量则降低到 ±10 个百分点。这些发现在匹兹堡地区使用烟尘颗粒气溶胶质谱仪进行的单颗粒测量得到了实验证实。版权所有 © 2020 美国气溶胶研究协会