Radiation Physics and Environment Group (FRYMA), Department of Integrated Sciences, Center for Natural Resources, Health and Environment (RENSMA), University of Huelva, 21071, Huelva, Spain.
Radiation Physics and Environment Group (FRYMA), Department of Integrated Sciences, Center for Natural Resources, Health and Environment (RENSMA), University of Huelva, 21071, Huelva, Spain.
Environ Res. 2022 Nov;214(Pt 1):113817. doi: 10.1016/j.envres.2022.113817. Epub 2022 Jul 5.
In the past decades, particulate matter (PM) measurements have been used extensively in atmospheric sciences, as it allows studying the evolution of tracers for different atmospheric processes and the effects of atmospheric pollution on human health. However, measuring PM mass requires a constant control of the laboratory conditions due to its capacity to absorb humidity. For this reason, this study was focused on developing a novel, simple and precise methodology to determine the corrections of the filter mass due to humidity changes. The control and corrections are possible using a "control filter", which is always adapted to the environmental conditions of the laboratory. To check the consistency of this method, it was proved that the mass of any problem filter and that of the control filter behave in a very similar way. This allows quantifying the mass changes of any problem filter by using the control filter, where the problem filters and the control filter must have the same chemical composition and dimensions. To validate this methodology, a comparison was made between the methodology proposed in this study (Method-1) and the one proposed by the EPA (Method-2), which is generally applied. The particulate matter mass (m) was obtained for a problem filter for different weights, achieving similar values using both methods. However, Method-1 still provided reliable mass measurements for relative humidities very different from 50%, even as low as 18%. It was also proved that the adsorption or loss of water by the particulate matter can be neglected, since m is much smaller than the blank filter mass. Method-1 was also employed in several samplings carried out using three PM samplers to determine contaminants, such as Be and Pb, obtaining a good agreement between all particulate masses and activities measured by the three samplers for all samplings.
在过去的几十年中，颗粒物 (PM) 的测量在大气科学中得到了广泛应用，因为它可以研究不同大气过程示踪剂的演变以及大气污染对人类健康的影响。然而，由于其吸湿能力，PM 质量的测量需要对实验室条件进行持续控制。出于这个原因，本研究专注于开发一种新颖、简单和精确的方法，以确定由于湿度变化而对滤膜质量进行修正。通过使用“控制滤膜”可以实现控制和修正，该滤膜始终适应实验室的环境条件。为了检查该方法的一致性，证明了任何问题滤膜的质量与控制滤膜的质量的行为非常相似。这允许通过使用控制滤膜来量化任何问题滤膜的质量变化，其中问题滤膜和控制滤膜必须具有相同的化学组成和尺寸。为了验证该方法，将本研究中提出的方法（方法 1）与 EPA 提出的（方法 2）进行了比较，后者通常被应用。对于不同重量的问题滤膜，获得了颗粒物质量（m），两种方法都得到了相似的值。然而，即使在相对湿度远低于 50%（低至 18%）的情况下，方法 1 仍能提供可靠的质量测量。还证明，颗粒物吸附或失去水分可以忽略不计，因为 m 远小于空白滤膜的质量。方法 1 还应用于使用三个 PM 采样器进行的几次采样中，以确定污染物，如 Be 和 Pb，对于所有采样，三个采样器测量的所有颗粒物质量和活性之间都得到了很好的一致性。
