This work quantifies the natural ice nuclei particle (INP) concentration activated at temperatures (T) lower than −29 °C in Córdoba, a city located in a semiarid region in the center of Argentina. Laboratory INP concentration measurements were performed in a cloud chamber where water supersaturation was reached by an adiabatic isobaric mixture of two air masses with different relative humidities. Once the activated INPs grew up to form ice crystals, these crystals were detected and quantified due to the sparkles they produce when they reflect the light incident on them. Following this methodology, a total of 123 ice crystal (i.e. INP) concentration measurements were performed at a T range of −29 °C to −48 °C.From these measurements it was found that the values of the INP concentration increased with T between −29 °C and approximately −38 °C, but they remained almost constant with T between −38 °C and − 48 °C. This behavior could be related to the dependence of the number of active sites with T. The INP concentration measurements obtained in this work were compared with those reported in recent studies. In addition, considering the elemental composition of the particulate matter in the site of study, we hypothesized that aluminosilicate minerals could be responsible for the INP measurements presented. This assumption was also made by comparing the obtained measurements with different parameterizations reported in the literature. Even though this hypothesis deserves to be tested, this study reports the first INP concentration measurements at temperatures lower than −30 °C in Argentina being one of the few works reporting such measures in the Southern Hemisphere.

这项工作对位于阿根廷中部半干旱地区的科尔多瓦市（Córdoba）中低于-29°C的温度（T）激活的天然冰核颗粒（INP）浓度进行了量化。实验室INP浓度测量是在云室中进行的，其中两个相对湿度不同的空气的绝热等压混合物达到了水的过饱和。一旦激活的INP长大形成冰晶，由于它们反射入射光时产生的火花，就可以对这些晶体进行检测和定量。按照这种方法，在-29°C至-48°C的T范围内进行了总共123个冰晶（INP）浓度测量。从这些测量中发现，INP浓度值随T在−29°C和大约−38°C，但它们在-38°C至-48°C的温度范围内几乎保持恒定。这种行为可能与活性位点数量与T的依赖性有关。这项工作中获得的INP浓度测量值与最近的研究报告进行了比较。此外，考虑到研究现场中颗粒物质的元素组成，我们假设铝硅酸盐矿物可能是提出的INP测量的原因。通过将获得的测量值与文献中报道的不同参数进行比较，也做出了这一假设。尽管该假设值得验证，但该研究报告了阿根廷在低于−30°C的温度下进行的首次INP浓度测量，这是南半球报告这种测量值的少数工作之一。