An investigator is comparing the rate of oxygen diffusion across the respiratory membrane between a healthy control cohort (Cohort 1) and a cohort of patients with advanced emphysema (Cohort 2).

In Cohort 1 (Healthy):

• Average total alveolar surface area ($A_1$) = 75.0 m²
• Average diffusion path length ($x_1$) = $0.50\mu m$

In Cohort 2 (Emphysema):

• Average total alveolar surface area ($A_2$) = 30.0 m²
• Average diffusion path length ($x_2$) = $0.80\mu m$

Assuming the partial pressure gradient of oxygen ($\Delta P$) across the respiratory membrane is identical in both cohorts, determine the factor by which the rate of oxygen diffusion is reduced in Cohort 2 compared to Cohort 1.

Use Fick's Law of Diffusion:

$$Rate\; of\; Diffusion\propto \frac{Surface\; Area\times Concentration\; Difference}{Diffusion\; Path\; Length}$$