Equilibrium sorption of gaseous organic chemicals to fiber filters used for aerosol studies

Abstract

Fiber filters commonly used to collect aerosols for various analyses also collect gaseous organic chemicals during sampling. These sorbed chemicals can lead to serious artifacts, particularly when analyzing aerosols for organic compounds and organic carbonaceous material. To date, this sorption process has only been looked at for a few types of filters and compound classes. This work presents a comprehensive study of this sorption process for various, widely used fiber filters and a broad variety of compound classes. Furthermore, important factors have been investigated, including relative humidity, temperature, baking and exposure to ambient air during sampling. From these data, poly-parameter linear-free energy relationships were derived that allow for estimations of sorption constants of gaseous organic compounds on different filter types. Based on the results, recommendations are provided to help predict, minimize and ensure reproducibility of artifacts caused by gaseous organic compounds sorbing to fiber filters.