Elemental and isotopic compositions in blank filters collecting atmospheric particulates
Background: The atmospheric particulates can be harmful to human health due to toxic substances sorbed onto particulates. Although the atmospheric particulates have been collected using different types of filters, few studies have reported background contents of major and trace element, and isotopic compositions in the blank filters used for collecting the particulates yet. Here, we first report background contents of major and trace elements, and isotopic compositions (Zn and Pb isotopes) in the blank filters. Then, we evaluate the best type of filter for elemental and isotope analyses in the particulates.
Findings: The contents of major elements are the lowest in the PTFE filter and become higher in the order of the Nylon, NC, and GF filters, indicating that either PTFE and/or Nylon filters are the most suitable for major element analysis in the atmospheric particulates. Likewise, the contents of trace elements are the lowest in the PTFE filter and become much higher in the order of the Nylon, NC, and GF filters, indicating that PTFE filter is the most suitable for trace element analysis in the atmospheric particulates. Otherwise, background elemental contents result in overestimating their concentrations in the atmospheric particulates. All δ66ZnJMC-Lyon values in two GF filters are within those from samples of the Chinese deserts and of the Chinese Loess Plateau. Likewise, their 206Pb/204Pb ratios are similar with those of samples from Xi’an and Beijing, indicating that the GF filter is not suitable for Zn and Pb isotope study in the atmospheric particulates.
Conclusions: This study suggests that the PTFE filter is the most suitable for elemental and isotope study in the atmospheric particulates and that the GF filter cannot be used for source identification in the atmospheric particulates using Zn and Pb isotopes.