Li Xiao-Xiao, Zhang Qiang, Deng Jian-Guo, Jiang Jing-Kun, Hao Ji-Ming
School of Environment, Tsinghua University, Beijing 100084, China.
Huan Jing Ke Xue. 2017 Aug 8;38(8):3095-3101. doi: 10.13227/j.hjkx.201612265.
In recent years, China has suffered a lot from atmospheric particles. Many studies of particles are based on filters. As a result, the accuracy of filter weighing is of great importance. A weighing chamber (1.2 m×0.6 m×0.8 m) was developed and evaluated using saturated MgCl solution with a self-made flow control system to maintain constant relative humidity (RH). By evaluating the mass change of blank and aerosol-enriched filters after weighing in different RH, we selected RH of 30%-40% as the range for the proper constant RH. To reach a constant RH, 20 L·min dry air was put through a RH-constant chamber with MgCl solution in it. Then, the RH-constant air was put continually into the weighing chamber. After the weighing chamber reached stable RH, the flow rate was adjusted to 5 L·min to maintain the RH. Throughout a one-month test, the weighing chamber maintained 30.1%-34.0% RH while the outside RH changed a lot. We weighed 60 filters with this weighing chamber after equilibration for 24 hours. The standard deviation after three times' weighing was no more than 0.02 mg. compared to other methods, the RH-controlling method of this weighing chamber was simple, stable, easy to maintain, and cost effective.
近年来，中国深受大气颗粒物之苦。许多关于颗粒物的研究都是基于过滤器进行的。因此，过滤器称重的准确性至关重要。我们开发了一个称量室（1.2米×0.6米×0.8米），并使用饱和氯化镁溶液和自制的流量控制系统对其进行评估，以保持相对湿度（RH）恒定。通过评估在不同相对湿度下称重后空白过滤器和气溶胶富集过滤器的质量变化，我们选择30%-40%的相对湿度作为合适的恒定相对湿度范围。为了达到恒定的相对湿度，将20升·分钟的干燥空气通入装有氯化镁溶液的恒湿室。然后，将恒湿空气持续通入称量室。称量室达到稳定的相对湿度后，将流速调整为5升·分钟以维持相对湿度。在为期一个月的测试中，当外部相对湿度变化很大时，称量室的相对湿度保持在30.1%-34.0%。在平衡24小时后，我们用这个称量室称量了60个过滤器。三次称重后的标准偏差不超过0.02毫克。与其他方法相比，这个称量室的相对湿度控制方法简单、稳定、易于维护且成本效益高。
