## 2 Materials and Methods
### Derivation of Integrated Indicator of Air Quality  
The integrated indicator for air quality assessment (IAQA) was developed to compare the selected agricultural settings based on the measured variables. The calculations were performed using a Microsoft Excel spreadsheet. Initially, to develop the IAQA, the readings had to be modified as their units of measurement were different. To adjust the readings between zero and one, Equation (5) was used [37].  
\[\text{XN}=\frac{(\text{Xi}-\text{Xmin})}{(\text{Xmax}-\text{Xmin})} \tag{5}\]  
where XN is the normalized reading value, Xi is the original reading value, Xmin is the lowest value among the original readings for one variable, and Xmax is the largest value among the original readings for one variable. This method (Equation (5)) gives no dimension to these original data. Additionally, the rationale behind the assigned weights to each variable should be elaborated upon to justify their selection. A weight of 1 to 5 was assigned to each variable, depending on its importance. Additionally, the rationale behind the assigned weights to each variable should be elaborated upon to justify their selection. A weight of 5 was used for the dust concentration (particulate matter) in the air because of its major role in pollution; however, particulate matter is an important parameter in determining air quality, affecting visibility [38], human health [39; 40], and global climate [41]. However, particles vary in size, shape, and composition. Moreover, particulate matter is the most commonly monitored indoor air pollutant, which is defined as a mixture of solid or liquid particles suspended in air [42]. Additionally, a weight of 4 was used for the carbon monoxide concentration as CO is produced indors by combustion sources (cooking and heating) and is also introduced through the infiltration of carbon monoxide from outdoor air into the indoor environment [43; 44]. Moreover, a weight of 2 was used for the air temperature variable and a weight of 3 for the air relative humidity. Finally, a weight of 1 was used for the atmospheric pressure. According to the IAQA values, the environment with the lowest value is the best environmentally, and the equation that calculated the IAQA is as follows:  
\[\text{IAQA}=\left(\frac{\sum_{i=1}^{n}(\text{XN}\,\text{D}\times 5+\text{XNCO} \times 4+\text{XNRH}\times 3+\text{XNT}\times 2+\text{XNP}\times 1)}{(5+4+3+2+1)} \right)\times 100 \tag{6}\]  
Figure 2: Some images of the agricultural actions in this research.  
Then, the arithmetic average of the IAQA (%) is averaged over the monitoring period.  
Where XND is the reading value after adjusting for the dust concentration in the air; XNCO is the reading value after adjusting for the carbon monoxide concentration; XNRH is the reading value after adjusting for the air relative humidity; XNT is the reading value after adjusting for the air temperature; XNP is the reading value after adjusting for the variable of atmospheric pressure, and n is the number of reads per site. In a previous study, the weighted linear combination method was used by [PERSON] et al. [45] to assess the appropriateness of agricultural land.