## 3 Materials and Methods
### Feature Vector Construction
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Research Paper** & **Predicted** & **Predictors** & **Models** & **Metrics** \\ \hline Estimation of Air Pollution in Delhi Using Machine Learning Techniques (2018) [11] & Air pollution levels for \(CO\), \(NO_{2}\), \(O_{3}\), \(SO_{2}\), \(PM_{10}\), \(PM_{2.5}\). & Vertical wind, Wind speed and direction, Relative humidity. & Linear Regression, Stochastic Gradient Descent, Random Forest, Decision Tree, Support Vector Regression, Multi-layer Perceptron, Gradient Boosting & RMSE, MAE, \(R^{2}\). \\ \hline  & & Air temperature, Relative humidity, Wind speed, and direction, Wind gust, Precipitation accumulation, Visibility, Dew point, Wind cardinal direction, Pressure, Weather conditions, Weekday/weekend, Concentration pollutant, and Bias term. & Air temperature, Relative humidity, Wind speed, Dew point, Pressure, \(PM_{2.5}\) Concentration, Classification Forest. & & \\ Detection and Prediction of Air Pollution Using Machine Learning Models (2018) [13]. & Classification of Samples into Polluted or Non-Polluted Categories, \(PM_{2.5}\). & Temperature, Wind speed, Dew point, Pressure, \(PM_{2.5}\) Concentration, Classification result. & Autoregression, Logistic Regression. & MA, SDA, MAE. \\ \hline  & & Pollution level, Meteorological conditions (Temperature, Relative humidity, Pressure, Wind speed, Rain), Calendar features (Year, Month, Day in the month, Day in the week, Hour), and Traffic intensity features. & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._In the presence of sunlight, \(NO_{2}\) undergoes photodissociation, breaking down into nitrogen monoxide (\(NO\)) and a free oxygen atom (\(O\)). The symbol \"\(hv\)\" represents a photon of sunlight. 3. Formation of ozone: \[O+O_{2}\to O_{3}\] (2) The free oxygen atom (\(O\)) rapidly reacts with molecular oxygen (\(O_{2}\)) in the atmosphere to form ozone (\(O_{3}\)). 4. Reconversion: \[NO+O_{3}\to NO_{2}+O_{2}\] (3) Nitrogen monoxide (\(NO\)) can also react with the ozone (\(O_{3}\)) to form nitrogen dioxide (\(NO_{2}\)) and molecular oxygen (\(O_{2}\)). This essentially reduces the concentration of ozone. 5. VOCs Role in the Cycle: VOCs, in the presence of \(NO_{x}\) and sunlight, can generate more reactive intermediates, which will react with \(NO\) to form \(NO_{2}\). This reaction \"removes\" \(NO\) from the environment, allowing more ozone to form without it being quickly converted back to oxygen. In other words, the VOCs help \"tie up\" \(NO\), preventing it from immediately destroying the ozone that's been formed. Finally, it is important to show how the ozone concentration could be influenced by temporal factors such as the month, day of week, and hour, or by geospatial factors as longitude, latitude and altitude; you can see a brief explanation of how each of these variables might impact ozone concentration:  
1. Month: * Sunlight Intensity and Duration: Ozone formation is a photochemical process that requires sunlight. Therefore, months with longer daylight hours and more intense sunlight, typically the spring and summer months, tend to have higher ozone concentrations. * Temperature: Months with warmer temperatures, typically summer months, can lead to higher ozone concentrations. * Vegetation Growth and Emissions: Certain months, especially spring and early summer, might see increased biogenic emissions of volatile organic compounds (VOCs) from vegetation, which can contribute to ozone formation. 2. Day of week: * Emissions Variability: Weekdays often have higher vehicular traffic and industrial activities compared to weekends. This can lead to higher emissions of ozone precursors like \(NO_{x}\) on weekdays. * Weekend Effect: Despite reduced precursor emissions on weekends, some urban areas observe higher ozone levels during weekends, a phenomenon known as the \"weekend effect.\" This can be due to the disproportionate reduction in \(NO\) emissions compared to VOCs on weekends, altering the chemical balance and facilitating ozone production. 3.