# Black Carbon in the Air of the Baikal Region, (Russia): Sources and Spatiotemporal Variations
## 3 Results and Discussion
### Black Carbon in the Air Basin of Lake Baikal
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Emission Type** & **Area** & **PM\({}_{2.5}\) Average** & \begin{tabular}{c} **Mean eBC \(\pm\) SD,** \\ **ug m\({}^{-3}\)** \\ \end{tabular} & **Min** & **Max** & **\(N\)** \\ \hline Background level & \begin{tabular}{c} South coast, \\ 06–08 August 2023 \\ West coast, \\ 08–09 August 2023 \\ East coast, \\ 10–13 August 2023 \\ \end{tabular} & 2.29 & 0.27 \(\pm\) 0.09 & 0.16 & 0.65 & 81 \\ \hline \multirow{4}{*}{\begin{tabular}{c} Anthropogenic \\ impact \\ \end{tabular} } & \begin{tabular}{c} Netwennichny Bay, west coast \\ 05 August 2023 \\ 05 August, \\ 05 August, \\ 05 August 2023 \\ 05 August, \\ 14–15 August 2023 \\ \end{tabular} & 1.87 & 0.26 \(\pm\) 0.03 & 0.16 & 0.37 & 119 \\ \cline{1-1}  & \begin{tabular}{c} East coast, \\ 10–13 August 2023 \\ \end{tabular} & 0.80 & 0.19 \(\pm\) 0.08 & 0.07 & 0.74 & 244 \\ \hline \multirow{4}{*}{\begin{tabular}{c} Anthropogenic \\ impact \\ \end{tabular} } & \begin{tabular}{c} Listvennichny Bay, west coast \\ 05 August 2023 \\ 05 August, \\ 05 August, \\ 14–15 August 2023 \\ \end{tabular} & 1.83 & 0.40 \(\pm\) 0.20 & 0.22 & 0.84 & 11 \\ \cline{1-1}  & \begin{tabular}{c} Angara River source, \\ 05 August, \\ 14–15 August 2023 \\ \end{tabular} & 1.65 & 0.94 \(\pm\) 1.40 & 0.16 & 7.02 & 98 \\ \cline{1-1}  & \begin{tabular}{c} Slyudyanka town, \\ 06–07 August 2023 \\ \end{tabular} & 4.21 & 1.85 \(\pm\) 1.42 & 0.32 & 6.3 & 46 \\ \cline{1-1}  & \begin{tabular}{c} Baikalak town, \\ 07 August 2023 \\ \end{tabular} & 2.55 & 0.33 \(\pm\) 0.08 & 0.22 & 0.45 & 15 \\ \cline{1-1}  & \begin{tabular}{c} Kluzhir settlement, \\ 08 August 2023 \\ 09–10 August 2023 \\ \end{tabular} & 2.28 & 0.64 \(\pm\) 0.19 & 0.36 & 0.94 & 12 \\ \cline{1-1}  & \begin{tabular}{c} Severyobaikalsk town, \\ 09–10 August 2023 \\ \end{tabular} & 1.91 & 0.22 \(\pm\) 0.12 & 0.11 & 0.59 & 55 \\ \cline{1-1}  & \
\begin{tabular}{c} Barguzin River mouth, \\ 12–13 August 2023 \\ \end{tabular} & 2.03 & 0.30 \(\pm\) 0.20 & 0.13 & 0.95 & 34 \\ \cline{1-1}  &
\begin{tabular}{c} Bolshoye Goloustroye settlement, \\ 14 August 2023 \\ \end{tabular} & 4.00 & 0.76 \(\pm\) 0.14 & 0.64 & 1.09 & 10 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Statistical analysis of different types of BC emissions (eBC) into the water area of Lake Baikal, 2023. The evening and morning maximum values resulted from the weakening of convective mixing, temperature inversion in the early morning hours, and the lowest depth of the atmospheric boundary layer, deteriorating the dispersion of impurities coming from air pollution sources located on the coast. The maximum value of 2.67 \(\upmu\)g m\({}^{-3}\) was recorded at 20:00, with a minimum concentration during daylight hours (0.25 \(\upmu\)g m\({}^{-3}\)). Black Carbon in the Air near the Listyanka Station: Seasonal Variability and Main Air Pollution Sources  
Local and regional scale meteorological factors have a significant impact on the transport and spatiotemporal variability in concentrations of air pollutants, including eBC to the coast and Lake Baikal. The eBC sources in the Baikal region can be conditionally divided into low (road and water transport, stove heating), emissions of which are mainly local, and regional (primarily coal-fired thermal power plants in large urban agglomerations). Atmospheric processes of regional and synoptic scales can carry emissions of the latter, owing to high pipes (150-200 m or more), over long distances in the boundary layer. In particular, the rural atmosphere monitoring station <<Listvyank>> also periodically experiences the influence of such regional transport, mostly in winter and rarely in summer. Automatic air pollution monitoring techniques applied at the Listvyanka station assess mutual correlations of eBC concentrations and gas impurities of sulfur and nitrogen in real time. Table 3 shows variability statistics of eBC concentrations at the Listvyanka station for 2023 and early 2024.