Concerns about the effect of atmospheric aerosol particles have been increasing in recent years and its impact on global climate, air pollution and human health have been studied extensively. Recent reports of extremely high concentration levels of PM2.5 in China have drawn worldwide attention to this issue as well.
PM2.5 are small particles suspended in the atmosphere with diameter less than 2.5 μm. The size is sufficiently small such that breathing can cause the particles to enter deep regions in the lungs where the air and blood are in intimate contact. This has raised concern not only about its effect on the respiratory but also on the cardiovascular system.
Elemental analysis of atmospheric aerosols including PM2.5 is an important means that can provide information about its source and environmental impact. In Japan, for the analysis of inorganic elements of PM2.5, acid decomposition of the collected sample followed by inductively coupled plasma-mass spectrometry (ICP-MS) method has been recommended. However, the sample preparation of this analysis method is complicated and analysis error can vary depending on the operator. Furthermore, the sample can not be recovered after measurement since ICP-MS requires that the sample be dissolved in an acid solution.
To overcome these issues, the Japanese ministry of environment established a “Guideline for Component Analysis of PM2.5” in 2007 which is a simple and nondestructive analysis method of inorganic elements by X-ray fluorescence (XRF) analysis. The guideline was partially revised in 2013 describes the analysis process of PM2.5 by XRF more concretely.