## 3 Results
While Valle del Cauca, Cundinamarca, Norte de Santander, Antiquia, and Cesar departments reported a total increase of 1262 Gg CO\({}_{2}\). Overall, the net reduction in Colombia was approximately of 4743 Gg CO\({}_{2}\) (Table A4). Considering the significant emission reduction of CO\({}_{2}\) in Bogota D.C., associated with road transportation and its population density, we also analyzed data from five air quality traffic stations in Bogota. In addition, we evaluated the concentrations of CO, SO\({}_{2}\), NO\({}_{2}\) and O\({}_{3}\) during the lockdown period ranging from April to June 2020 and compared these to the same period in 2018. We observed significant air quality improvements through a decrease in CO, SO\({}_{2}\) and NO\({}_{2}\) in areas influenced by vehicular traffic. Drastic reductions in CO (up to \(-\)60.85%), SO\({}_{2}\) (up to \(-\)73.23%), and NO\({}_{2}\) (up to \(-\)60.60%) concentrations were observed in the urban area during the lockdown, as shown in Table 2. By contrast, an increase of up to 106.32% (in May) in ozone concentrations was observed in urban areas of Bogota. Figure 5 shows NO\({}_{2}\) concentration reductions visualized by satellite measurement of background tropospheric data available from OMI. The levels of NO\({}_{2}\) over Colombia decreased substantially in the Central Region during the lockdown (April to June 2020) compared to the same period in 2018. Nevertheless, the north region showed an increase in the levels of NO\({}_{2}\) over Atlantico, Bolivar, Cesar, La Guajira and Magdalena departments. Figure 3: Emissions variations of the four groups of pollutants in the study: (**a**) GHGs; (**b**) ozone precursors; (**c**) aerosols; (**d**) acidifying gases, during the January to June 2020 in relation to the same period of 2018. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{
\begin{tabular}{c} **Air Pol-** \\ **lutant** \\ \end{tabular} } & \multicolumn{2}{c}{**Mean Concentration 2018 (\(\text{\mu g.m}^{-3}\))**} & \multicolumn{2}{c}{**Mean Concentration 2020 (\(\text{\mu g.m}^{-3}\))**} & \multicolumn{2}{c}{**Variation of Mean Concentrations (\%) from 2018**} \\ \cline{2-9}  & **Apr** & **May** & **Jun** & **Apr** & **May** & **Jun** & **Apr** & **May** & **Jun** \\ \hline \multirow{2}{*}{CO} & 1408.75 \(\pm\) & 1269.63 \(\pm\) & 1074.67 \(\pm\) & 551.55 \(\pm\) & 787.13 \(\pm\) & 920.46 \(\pm\) & \multirow{2}{*}{\(-\)60.85} & \multirow{2}{*}{\(-\)38.18} & \multirow{2}{*}{\(-\)13.8} \\  & 363.64 & 304.62 & 396.98 & 276.74 & 301.38 & 422.75 & & & \\ \(\text{SO}_{2}\) & 3.90 \(\pm\) 2.00 & 3.41 \(\pm\) 1.26 & 4.50 \(\pm\) 1.50 & 2.83 \(\pm\) 1.19 & 3.30 \(\pm\) 2.06 & 4.13 \(\pm\) 2.15 & & & \\ \(\text{NO}_{2}\) & 56.10 \(\pm\) 12.20 & 44.70 \(\pm\) 7.82 & 46.60 \(\pm\) 7.46 & 22.10 \(\pm\) 9.75 & 27.80 \(\pm\) 14.46 & 29.30 \(\pm\) 12.59 & & & \\ \(\text{O}_{3}\) & 14.66 \(\pm\) 6.88 & 10.28 \(\pm\) 3.95 & 13.06 \(\pm\) 6.75 & 37.53 \(\pm\) 13.61 & 21.21 \(\pm\) 7.07 & 18.16 \(\pm\) 7.43 & 60.92 & 106.32 & 27.66 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Mean concentration and standard deviation of CO, \(\text{SO}_{2}\), \(\text{NO}_{2}\) and \(\text{O}_{3}\) in Bogotá during the lockdown (April to June 2020) compared to the same period in 2018 [54]. Figure 4: Spatial distribution of \(\text{CO}_{2}\) emissions variation through internal political and territorial divisions (departments). Warm and cold colors indicate an increase and decrease, respectively, in emissions between the March and June 2018 and 2020.