## 2 Materials and Methods
### Design of the Decision Matrix  
Given our research aim of developing a decision-making tool to evaluate the implementation of pneumatic solid urban waste collection systems in municipalities, aligned with the United Nations Sustainable Development Goals (SDGs), a decision matrix was chosen. Recognized as a key tool for evaluating various alternatives considering multiple determining factors influencing the final decision, the decision matrix was selected for its effectiveness, stemming from its simplicity and speed in assessing different alternatives considering multiple relevant factors. This allows for a preliminary response to the research question effectively and efficiently, without requiring complex calculations. The purpose of this matrix is to assess, through a numerical evaluation, the suitability of implementing a pneumatic municipal solid waste collection system in a specific municipality or area within it. Its construction involves the cross-referencing of information between the study variables and the Sustainable Development Goals (SDGs) established by the United Nations. This strategy not only allows the precise visualization of the relationship between the two entities but also enables their quantification. This relationship is supported by surveys of system users and technicians responsible for the logistics of municipal cleaning systems. The development of relevant assessments involves the participation of experts in waste collection systems and associated logistics. The opinions of these experts, based on experience and knowledge, will be collected using fixed-value scales. This technical procedure will facilitate the quantitative interpretation of the variables. Each variable in the study has been associated with two different values: Magnitude (M) and Impact (I). Figure 1 represents each cell of the decision matrix corresponding to a specific variable and its relationship to various Sustainable Development Goals (SDGs). Magnitude (M), derived from the survey results, is represented in the upper left corner of \begin{table}
\begin{tabular}{c l} \hline \hline \multicolumn{1}{c}{**Questions**} \\ \hline
8 & Level of satisfaction with the pneumatic solid urban waste collection system \\
9 & In pneumatic waste collection systems, do you think that a higher implementation cost compensates for a lower operating cost? \\
10 & Reduce contact with waste for users and waste collection professionals. \\
11 & Reduce the circulation of vehicles within cities. \\
12 & Waste collection systems integrated with SMART cities where waste doors can be opened automatically. \\
13 & Identification, monitoring, weighing, and invoicing in real time about waste disposed. \\
14 & Dump the waste generated by any citizen at any time of the day, any day of the year. \\
15 & PUSWCS improve selective waste collection. \\
16 & PUSWCS contribute to improving sustainability and the environment. \\
17 & PUSWCS contribute to a better quality life of people. \\
18 & PUSWCS improve production and consumption patterns. \\
19 & PUSWCS promote the circular economy. \\
20 & PUSWCS lower CO\({}_{2}\) emissions. \\
21 & PUSWCS lower greenhouse gas emissions. \\
22 & PUSWCS generate less noise during the waste collection process. \\
23 & PUSWCS reduce odors at waste disposal points for citizens. \\
24 & PUSWCS are not affected by workers’ strikes. \\
25 & PUSWCS reduce operating wage costs. \\
26 & PUSWCS are less exposed to possible vandalism acts than traditional collection systems. \\
27 & PUSWCS reduce the occupation area for waste collection on public streets. \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Survey questions to assess the importance and satisfaction of the variables considered regarding the PUSWCS. each cell, while Impact (I), which indicates the significance of this magnitude in relation to the SDGs, is represented in the lower right corner of each cell.