## 3 Results and Discussions
### Analysis of the Rasch Measure: Atmospheric Pollution
The straight line represents the latent variable: atmospheric pollution. Days in 2016 (each black point is 4 days and each grey point is 1 to 3 days) are represented above the line according to their atmospheric pollution measure: to the right those when higher atmospheric pollution level occurred; to the left those when lower atmospheric pollution level occurred. Individual pollutants and climatic factors are below the line: to the right those with lower influence on atmospheric pollution (rare); to the left those with higher influence on atmospheric pollution (frequent). Rainfall represents the lack of precipitation, RH is the relative humidity, SR is the solar radiation, TMP is the mean air temperature, PRB is the barometric pressure, and BENZ is benzene. In both urban locations, ozone is the most influential pollutant on the environmental deterioration. Similarly to Monfrague, the climatic variables which influence ozone generation are around it, denoting their relationship. However, some others individual pollutants exert a limited influence on urban atmospheric pollution, as SO\({}_{2}\), PM\({}_{10}\), and NO\({}_{2}\), mainly produced from motor vehicles and other fuel combustion processes. In general, it was apparent that the considered climatic factors (except precipitation) are aggregated, close to tropospheric ozone, and the individual pollutants are distributed along the line. However, some of them, located to the right in the continuum, have very low score, denoting their low influence on the atmospheric pollution. In consequence, a ranking of all the considered items have been obtained as an output of the Rasch model. According to the order established after processing all data, CO is the pollutant with higher measure, followed by NO, NO\({}_{\times}\), and benzene in the urban sites, and NO\({}_{2}\) \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Item**} & \multicolumn{3}{c}{**Badajoz**} & \multicolumn{3}{c}{**Cáceres**} & \multicolumn{3}{c}{**Monfragüe**} \\ \cline{2-9}  & **Total Score** & **Measure** & **Total Score** & **Measure** & **Total Score** & **Measure** \\ \hline CO & 338 & 3.88 & 325 & 2.57 & 355 & 2.65 \\ NO & 372 & 2.03 & 345 & 1.91 & 390 & 1.68 \\ NO\({}_{\times}\) & 476 & 0.85 & 479 & 0.53 & 520 & 0.43 \\ Benzene & 577 & 0.36 & 418 & 0.92 & 363 & 2.34 \\ PM\({}_{10}\) & 585 & 0.33 & 623 & \(-\)0.02 & 534 & 0.36 \\ NO\({}_{2}\) & 674 & 0.04 & 568 & 0.15 & 359 & 2.48 \\ SO\({}_{2}\) & 745 & \(-\)0.16 & 654 & \(-\)0.11 & 697 & \(-\)0.29 \\ Barometric pressure & 863 & \(-\)0.45 & 604 & 0.03 & 1042 & \(-\)1.18 \\ Temperature & 964 & \(-\)0.68 & 839 & \(-\)0.56 & 979 & \(-\)1.03 \\ O\({}_{3}\) & 991 & \(-\)0.74 & 941 & \(-\)0.78 & 1154 & \(-\)1.45 \\ Relative humidity & 1010 & \(-\)0.78 & 867 & \(-\)0.62 & 989 & \(-\)1.06 \\ Solar radiation & 1021 & \(-\)0.81 & 937 & \(-\)0.77 & 1046 & \(-\)1.19 \\ Rainfall & 1633 & \(-\)3.88 & 1488 & \(-\)3.27 & 1619 & \(-\)3.72 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Influence of each pollutant and climatic factor on the atmospheric pollution. Total score is the sum of the points of the common scale for each item considering all days in 2016; measure is the atmospheric pollution level. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Day**} & \multirow{2}{*}{**Rainfall**} & \multirow{2}{*}{ \begin{tabular}{c} **Solar** \\ **Radiation** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Relative** \\ **Humidity** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **O\({}_{3}\)** \\ **Temperature** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Bamometric** \\ **Pressure** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **SO\({}_{2}\)** \\ **PS** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **NO\({}_{2}\)** \\ **PS** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **NO\({}_{2}\)** \\ **PS** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **PM\({}_{10}\)** \\ **PS** \\ \end{tabular}  } & \multirow{2}{*}{