An industrial stack emits $100 \mathrm{~g} / \mathrm{s}$ of $\mathrm{CO}$ at an effective height of ' $\mathrm{H}$ ', where the wind speed is $5 \mathrm{~m} / \mathrm{s}$. At $3 \mathrm{~km}$ distance downwind, the values of dispersion coefficient in $\mathrm{y}-$ direction and z-direction are $50 \mathrm{~m}$ and $25 \mathrm{~m}$, respectively. The $\mathrm{CO}$ concentration at the centerline of the plume at $3 \mathrm{~km}$ distance downwind is __________ $\mathrm{mg} / \mathrm{m}^{3}$ $\text{(rounded off to 2 decimal places)}$?
Use Gaussian plume model and value of $\pi=3.14$. Neglect reactions and the ground effect of plume in the calculations.
