calculation, or you can write a computational program.

$18\mathrm{.}9$ A facility emits $100gS\frac{O_2}{s}.$ On relatively clear nights $($slight cloud cover$)$

and a wind speed of $2\frac{m}{s},$ the maximum ground level $S{O}_2$ concentration cannot exceed

$60\frac{g}{m^3}.$ If the only control on $S{O}_2$ emission is stack height, what would the effective

stack height have to be$?$