Currently, there is a lack of research directly comparing the precision of automatic weighing systems and manual weighing in the context of particulate matter (PM) filter equilibration and measurements under different humidity conditions. During experimental measurements, three different types of PM-loaded filters were weighed using manual and automatic balances. During manual weighing, every filter was weighed twice in three different relative humidity conditions. The same procedure was done using an automated weighing system. In most cases, it was found that under relative humidities in the range of 30–55% RH, the manual and automated methods can be treated as referential. Regarding device stability, very slight but overall better precision was found for 30% RH, suggesting that 40 CFR Part 50, Appendix L requirements regarding conditioning humidity (30–40% RH) seem more suitable than those presented in the PN-EN 12341:2014 standard (45–50% RH). Understanding the effects of the influence of the RH% on PM mass measurements is a matter of great importance, because water vapor condensed on a filter can affect the particulate matter concentrations. This is especially important in areas where regulatory limits are exceeded. Calculation of uncertainty in the PM mass measurements is therefore crucial for determining the actual sample mass and improving air monitoring practices. In a nutshell, the experimental results obtained clearly describe how changing RH% conditions affect the PM weighing precision during manual and automated measurements.

Limited data on rural Poland's atmospheric ion concentrations exists, with no publicly available monitoring data in urban areas. These knowledge gaps hinder the comparison of concentrations across environments and the identification of their sources. This study examines water-soluble ions across five rural locations in Poland over four years to investigate their concentrations and sources in the atmosphere. This study explores aerosol origins, performing a four-year correlation analysis across five locations to reveal ion relationships. Notably, sulfate (SO₄²⁻), nitrate (NO₃⁻), and ammonium (NH₄⁺) exhibit significant correlations ranging from 0.3 to 0.8, suggesting a common pollution source in all analyzed rural locations. Interestingly, magnesium (Mg²⁺) and sodium (Na⁺) in two locations demonstrated a strong correlation, ranging between 0.4 and 0.9, suggesting the influence of sea spray on these sites. Principal component analysis is used to investigate the factors influencing ion concentrations, revealing distinctive patterns for each location and explaining the total variances ranging from 74.9% to 84.8%. This underscores the significance of geographical and environmental factors. The study's novelty lies in its thorough and long-term analysis of water-soluble ion concentrations across rural Poland, providing an extensive dataset for the region. The study fills a data gap on rural pollution sources and reveals consistent ion patterns across different sites and seasons. The findings emphasize geographical and environmental impacts on aerosol composition and suggest common pollution sources for all areas. This research encourages further investigations into the stability and origins of ions in rural environments, providing valuable insights for local and broader atmospheric studies.

The distribution of mass and the number of particles is a determining factor in the respirable nature of a given particulate matter (PM), and thus in the potential health effects of breathing the air in question. One of the most popular activities during the summer months is the preparation of food on a barbecue. Barbecuing represents one of the few sources of combustion particulates during the summer, a period which is otherwise characterised by a lack of heating. The objective of this study is to ascertain the fractional composition of PM emitted during food preparation on an electric barbecue and to compare these values with the measured background. The concentrations of particulate matter (PM) at the barbecue were determined with a Palas AQ Guard optical spectrometer, while the background concentrations were measured with a Palas Fidas 200 optical spectrometer that complies with the EN16450 standard. The contribution of the individual PM fractions measured in the barbecue environment differed from that observed in the ambient air. The background measurements exhibited a relatively well-defined and consistent distribution, with the PM₁ fraction representing between 10 and 30% of the PM mass and the PM₄₋₁ fraction accounting for only 10 to 20%. Thus, the mass of the PM₄ fraction did not exceed 50% of the total mass of particles. Upon analysis of the particles emitted during the grilling process, it was observed that the PM₁ fraction was capable of accounting for a substantial proportion, exceeding 90% of the PM mass. The trend related to the PM₄₋₁ fraction was maintained; however, the limit of the maximum content of this fraction increased to 40% of the PM. The results demonstrate that the barbecue process itself, utilising a barbecue without emission fuel, can exert a notable influence on the contribution of submicron PM.

Gravimetric quantification of atmospheric particulate matter (PM) is biased by particle-bound water that persists after routine filter conditioning, with the magnitude depending on chemical composition, mixing state, and the operational definition of "water" inherent to the analytical protocol. Here, particle-bound water was quantified by Karl Fischer (KF) coulometric titration combined with stepwise heating to differentiate weakly adsorbed from more strongly retained fractions. Thirty-five single-component chemicals and certified reference materials (CRMs) were analyzed at two mass loadings (0.6 and 2.0 mg), corresponding to typical summer and winter filter loads, together with artificial PM (aPM) mixtures examined as sequential-addition systems and as bulk samples of atmospherically relevant composition. Bulk KF measurements revealed marked class-dependent differences: deliquescent inorganic salts retained the largest water masses, whereas most metals, metal oxides, polycyclic aromatic hydrocarbons, and graphitic carbons approached analytical background. Water-to-solute molar ratios (W/S) enabled cross-compound comparison and demonstrated non-linear scaling with loading—absolute water generally increased with mass, but W/S decreased, consistent with reduced vapor accessibility in compacted powders. Principal component analysis of replicate-averaged W/S values confirmed that water retention is chemically stratified and predominantly one-dimensional, with PC1 explaining 98.5% of variance (intrinsic hygroscopicity) and PC2 (1.5%) capturing minor mass-dependent effects. Sequential aPM experiments showed that secondary inorganic species dominate retained-water contributions, and bulk aPM thermal release profiles closely matched those of ambient PM₁ filters. PM-bound water is best described as a continuum of binding states governed primarily by composition and modulated by loading, informing approaches to mitigate humidity-related bias in gravimetric PM determination.