At Standard Temperature and Pressure (STP), one mole of any gas occupies 22.4 liters (22.4 dm$^3$). The molar mass of CO$_2$ is 44 g/mol. To begin, determine the number of moles present in 4.48 dm$^3$ of CO$_2$: \[ \text{Moles of CO}_2 = \frac{4.48 \, \text{dm}^3}{22.4 \, \text{dm}^3/\text{mol}} = 0.2 \, \text{mol} \] Next, calculate the mass corresponding to 0.2 moles of CO$_2$: \[ \text{Mass} = 0.2 \, \text{mol} \times 44 \, \text{g/mol} = 8.8 \, \text{g} \] Lastly, convert the mass from grams to kilograms: \[ \text{Mass in kg} = \frac{8.8 \, \text{g}}{1000} = 4.4 \times 10^{-3} \, \text{kg} \]