The aim of the study was to assess the profile of EC (elemental carbon) and OC (organic carbon) temperature fractions in PM1 and PM2.5 samples and in wet deposition samples (material collected on a filter). The research was conducted at the urban background station in Zabrze (southern Poland) in the period of Oct 2020–Oct 2021. PM samples were collected with high-volume samplers; the automatic precipitation collector NSA 181 by Eigenbrodt was used to collect the deposition samples. Concentrations of EC and OC were determined using thermal-optical method (carbon analyzer from Sunset Laboratory Inc., “eusaar_2” protocol). Regardless of the type of research material, organic carbon constituted the dominant part of the carbonaceous matter, and this dominance was more visible in the non-heating season. The profile of temperature fractions of OC and EC was clearly different for dust washed out by precipitation. Noteworthy is a much lower content of pyrolytic carbon (PC) in OC, which can be explained by the fact that PC is most often combined with the water soluble organic carbon. In addition, a high proportion of the OC3 fraction was observed, followed by OC4, which may indicate that these fractions are of a more regional origin. With regard to the EC fractions, the differences are less visible and concern, in particular, the higher share of EC4 and the lower EC2. The obtained results may be a valuable source of information about the actual status of the carbonaceous matter and its transformation in the atmosphere. Introduction The deterioration of air quality and the increase in damage to ecosystems caused by the emission and subsequent deposition of particulate matter (PM) are currently among the main environmental problems (EEA 2022; Michalski & Pecyna-Utylska 2022). Among the various chemical species, carbonaceous matter is often the dominant part of the PM mass (Chow et al. 2015). The proportion of carbon compounds is generally higher in the finer fractions, accounting for an average of 20-60% of PM2.5 (particles with aerodynamic diameter < 2.5 μm) (Li et al. 2018). This share varies considerably in different regions of the world – generally higher values have been found in locations strongly influenced by anthropogenic emission sources, such as: road traffic, industrial plants, and fossil fuels combustion in households (Reizer and Juda-Rezler, 2016).

The paper presents two sample preparation procedures for the determination of aldehydes in wet deposition. In both cases the 2,4-dinitrophenylhydrazine derivatization and solid phase extraction were applied. The derivatization in method A was applied before the extraction, the extraction in method B was carried out with simultaneous derivatisation. Accuracy of both methods was evaluated on the basis of the analysis of aqueous solutions of selected carbonyl compounds. Both methods were characterized by good recovery, however, due to the precision of the method expressed as RSD for testing of environmental samples the method B was used.

The analysis of environmental samples showed significant differences in the concentrations of aldehydes in wet deposition, depending on the location of the sampling point. In the case of samples taken from agricultural areas the predominant aldehydes were formaldehyde and acetaldehyde. Formaldehyde was from 31% to 47% of the determined compounds. While in samples collected near a traffic source, in the deposition acrolein was determined at the levels from 62% to 64% of the identified compounds.