Seasonal and Meteorological Variability of Total Suspended Particulate Matter (TSP) in the Semi-Urban Atmosphere of Bayburt: An Integrated Assessment Based on OpenAir, PCA, and HYSPLIT

In this study, atmospheric Total Suspended Particulate Matter (TSP) concentrations in a semi-urban area of Bayburt Province were evaluated in terms of seasonal variation, temporal behavior with meteorological factors, and air-mass transport characteristics. TSP sampling was conducted using the active sampling method over 118 days during the cold and warm-seasons sampling campaign of 2022. A high-volume air sampler (HVAS) and glass fiber filters (GFFs) were used, and TSP concentrations were determined gravimetrically. The mean TSP concentration was 29.13 ± 29.39 µg/m3 in cold-season sampling campaign and 43.69 ± 27.62 µg/m3 in warm-season sampling campaign. According to standard tests, the seasonal difference was nominally statistically significant (p < 0.05; Cohen’s d ≈ 0.51; Cliff’s delta ≈ 0.38). However, this significance did not persist after adjusting for serial autocorrelation in the AR(1) model (p = 0.151). However, this comparison should be interpreted not as validated seasonal climatological data, but as a comparison between intermittent sampling studies conducted within a single calendar year. This is because the transition period from spring to summer was not included in the sampling, and the studies were not repeated from year to year. OpenAir analyses showed that high TSP concentrations were particularly associated with easterly and southerly airflows. No clear weekday/weekend difference was observed, although episodic increases occurred on several days. The first two principal components explained 77.8% of the total variance, while the high TSP loading on PC3 indicated complementary variability. NOAA-HYSPLIT backward air-mass trajectory analyses indicated regional transport pathways in most high-TSP episodes, whereas local atmospheric stagnation was prominent in one episode. Overall, the findings show that TSP variability in semi-urban areas should be evaluated together with seasonal–meteorological variability, potential local emission effects, and regional air-mass transport.