The research is based on the results of air quality monitoring for the period from 2000 to 2020. The air samples have been taken onboard the International Space Station (ISS) using AK-1M samplers and delivered to Earth. The representativeness of the research results is confirmed by the long-term duration (20 years of observation) and the amount of experimental data (analysis of more than 30,000 measured concentrations of chemicals identified by gas chromatography and mass spectrometry). Statistical analysis of measured concentrations showed that the vast majority (70%) of trace contaminants detected in the ISS air have a log-normal distribution, which is confirmed by the use of the Kolmogorov-Smirnov goodness-of-fit test (p > 0.2). For the remaining 30%, the significance level of the Kolmogorov-Smirnov goodness-of-fit criterion was less than 0.2, however, the statistical distributions of these trace contaminants are characterized by unimodality, peakedness (kurtosis coefficient significantly >2) and asymmetry (skewness coefficient >1) with a shift towards lower values, which regarded as a “close to normal distribution”. It has been established that the log-normal model can be accepted as a theoretical model describing the distribution of trace contaminants in the air of manned space stations. The established log-normal distribution and the ratio between the average concentrations of different averaging periods (10 : 3: 1.5 : 1) confirms the uneven nature of air pollutants in the modules and the possibility of the formation of “stagnant” zones. This is of great practical importance, which must be taken into account when establishing the air quality standards for trace contaminants and designing life support systems (ventilation and air purification) for manned space stations.

该研究基于 2000 年至 2020 年期间的空气质量监测结果。空气样本已使用 AK-1M 采样器在国际空间站 (ISS) 上采集并运送到地球。研究结果的代表性通过长期持续时间（20 年的观察）和大量的实验数据（对 30,000 多种通过气相色谱和质谱鉴定的化学物质的测量浓度进行分析）得到证实。测量浓度的统计分析表明，在国际空间站空气中检测到的绝大多数（70%）痕量污染物具有对数正态分布，这通过使用 Kolmogorov-Smirnov 拟合优度检验得到证实（p > 0.2 ）。对于剩余的 30%，Kolmogorov-Smirnov 拟合优度标准的显着性水平小于 0。然而，如图 2 所示，这些痕量污染物的统计分布具有单峰性、峰化（峰度系数显着 >2）和不对称（偏度系数 >1）的特征，并且向较低值移动，这被认为是“接近正态分布”。已经确定，对数正态模型可以被接受为描述载人空间站空气中痕量污染物分布的理论模型。建立的对数正态分布和不同平均时期的平均浓度之间的比率（10：3：1.5：1）证实了模块中空气污染物的不均匀性以及形成“停滞”区的可能性。这具有很大的实际意义，