## 4 Results and Discussion
### PAHs Sources  
It should be considered that, due to the longer accumulation time of PAHs in the snow cover compared to the air and its dependence on atmospheric conditions, it is extremely difficult to reliably determine the exact sources of PAHs. Therefore, to differentiate PAHs originating from environmental samples, diagnostic ratios between individual PAHs were introduced [1; 57; 58; 59]. To reduce distorting factors, such as variations in volatility, water solubility, and adsorption, ratio calculations are usually limited to PAHs of the same molecular mass [58]. Anthropogenic input and/or combustion are often concluded based on the increase in the proportion of the \"kinetically\" less stable PAHs isomers [57; 58]. Among the most common ratios used for provenance determination are Ant/Ph, Flt/Pyr, and low molecular weight (LMW) PAHs/ high molecular weight PAHs [10; 57]. Moreover, to deduce petroleum or combustion sources additional ratios of relative stability in the environment are employed: \(\mathrm{IcdP}/(\mathrm{IcdP}+\mathrm{BghiP})\) and Flt/(Flt + Pyr) [60]. The results of PAH diagnostic ratios for investigated samples are presented in the Table 4A. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Site**} & \multicolumn{4}{c}{(**A**)} \\  & \(\Sigma\)**COMB/** & **Ant/** & **Fl/** & **IcdP/** & **BaP/** & \(\Sigma\)**LMW/** & **BaA/** & \\  & \(\Sigma\)**PAH** & **(Ant + Ph)** & **(Flt + Pyr)** & **(IcdP + Bghi)** & **BghiP** & \(\Sigma\)**HMW** & **(BaA + Chr)** & **BaP\({}_{  
Combustion and petroleum sources are commonly distinguished using PAHs with molecular masses 178 and 202 u. For mass 178 u, an Ant/(Ant + Ph) ratio <0.10 usually indicates petroleum, while >0.10 combustion [1; 57] (Table 4B). The obtained results for Zawoja, except for sample 12, were below 0.10 and ranged from 0.02 to 0.09 (Table 4A), suggesting either an origin from petroleum or combustion of lignite/brown coal or No 2 fuel oil [58]. These ratios resemble the values obtained for urban air [58]. The only sample with extremely elevated values collected from the vicinity of the main church parking lot (site 12, Ant/(Ant + Ph) = 0.47) might indicate the presence of bituminous coal combustion. Another indicator based on mass 202 u is the Flt/(Flt + Py) ratio. A value of 0.50 for this ratio is considered a transition point between petroleum samples (<0.50) and kerosene, grass, wood, and coal combustion samples. Ratios between 0.40 and 0.50 are characteristic of liquid fossil fuels, and >0.50 indicate grass, wood, and coal combustion [58] (Table 4B). For the majority of the samples, the ratio exceeded Flt/(Flt + Py) = 0.50 (Table 4A), which leads to the conclusion that the origin of PAHs is related to the combustion of solid fossil fuels and biomass. PAHs of molecular masses 228 and 276 u are less commonly used as PAH source indicators [58], as generally present in significant amounts only in higher fractions of petroleum [63; 64] and likely in bitumen and coal [65]. [PERSON] et al. (2002) [58] attributed a BaA/(BaA + Chry) ratio > 0.20 to petroleum, 0.20-0.35 to petroleum or combustion, and >0.35 to combustion (Table 4B). Given that, the results of BaA/(BaA + Chr) for Zawoja ranged between 0.34 and 0.45, suggesting a mixed source of PAHs (Table 4A). For the IcdP/IcdP + BghiP) ratio, values < 0.20 are interpreted as petroleum combustion, between 0.20 and 0.50 as liquid fossil fuel combustion, and >0.50 as coal, grass, and wood combustion [58] (Table 4B). The aforementioned would suggest the origin of Zawoja PAHs (values 0.53-0.60, (Table 4A) from biomass and coal combustion. High values obtained for the BaP/BghiP ratio combined with Flt/(Flt + Py) indicate that coal and biomass combustion are the primary sources of PAHs [66]. PAHs typically produced from combustion processes are represented by the sum of: Flt, Pyr, BaA, BbF, BkF, BaP, DBaH, BghiP, and IcdP [67]. All compounds are HMW and contain between 4 and 6 rings.