Zervaki Orthodoxia, Dionysiou Dionysios D, Kulkarni Pramod
National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, OH, 45226, United States.
Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering (ChEE), University of Cincinnati, Cincinnati, OH, 45221, United States.
J Aerosol Sci. 2024 Nov;182. doi: 10.1016/j.jaerosci.2024.106442.
Trace measurement of aerosol chemical composition in workplace atmospheres requires the development of high-throughput aerosol collectors that are compact, hand-portable, and can be operated using personal pumps. We describe the design and characterization of a compact, high flow, Turbulent-mixing Condensation Aerosol-in-Liquid Concentrator (TCALC) that allows direct collection of aerosols as liquid suspensions, for off-line chemical, biological, or microscopy analysis. The TCALC unit, measuring approximately 12 × 16 × 18 cm, operates at an aerosol sample flowrate of up to 10 L min, using rapid mixing of a hot flow saturated with water vapor and a cold aerosol sample flow, thereby promoting condensational growth of aerosol particles. We investigated the effect of operating parameters such as vapor temperature, growth tube wall temperature, and aerosol sample flowrate, along with the effect of particle diameter, inlet humidity, aerosol concentration, and operation time on TCALC performance. Nanoparticles with an initial aerodynamic diameter ≥25 nm could grow to droplet diameters >1400 nm with an efficiency ≥80%. Good droplet growth efficiency was achieved for sampled aerosol relative humidity ≥9%. We measured complete aerosol collection for concentrations of ≤3 × 10 cm. The results showed good agreement between the particulate mass collected through the liquid collector and direct filter collection. The TCALC eliminates the need for sample preparation and filter digestion during chemical analysis, thereby increasing sample recovery and substantially improving the limit of detection and sensitivity of off-line trace analysis of collected liquid samples.
对工作场所空气中气溶胶化学成分进行痕量测量，需要开发紧凑、便于携带且可使用个人泵操作的高通量气溶胶收集器。我们描述了一种紧凑、高流量的湍流混合冷凝气溶胶液体浓缩器（TCALC）的设计与特性，该浓缩器可将气溶胶直接收集为液体悬浮液，用于离线化学、生物或显微镜分析。TCALC装置尺寸约为12×16×18厘米，在高达10升/分钟的气溶胶样品流速下运行，通过将饱和水蒸气的热气流与冷空气溶胶样品流快速混合，促进气溶胶颗粒的凝结增长。我们研究了诸如蒸汽温度、生长管壁温度和气溶胶样品流速等操作参数的影响，以及颗粒直径、入口湿度、气溶胶浓度和操作时间对TCALC性能的影响。初始空气动力学直径≥25纳米的纳米颗粒可以生长到液滴直径>1400纳米，效率≥80%。对于采样气溶胶相对湿度≥9%，可实现良好的液滴生长效率。我们测量了浓度≤3×10厘米时的完全气溶胶收集情况。结果表明，通过液体收集器收集的颗粒质量与直接过滤收集之间具有良好的一致性。TCALC在化学分析过程中无需进行样品制备和滤膜消解，从而提高了样品回收率，并显著提高了收集液体样品离线痕量分析的检测限和灵敏度。
