$(20$ points $-\%$ Carboxyhemoglobin$)$ Suppose an indoor "tractor pull" competition at the county

fair resulted in a CO concentration of $450ppmv.$

a$.$ What percentage COHb would result for a spectator who is exposed to one hour at this

level?

b$.$ How long would it take to reach $10$ percent COHb, which is a level at which most people

will experience dizziness and headache?$(20$ points $$ Indoor Air$)$ A single$-$story home with air exchange rate of $0\mathrm{.}8$ ach has $250$ m$2$ of floor

space and a total volume of $500$ m$3.$ If $1$ pCi$/$m$2$s of radon is emitted from the soil and enters the

house,

a$.$ Estimate the steady$-$state indoor radon concentration $($pCi$/$L$).$ Should this home take

measures to lower the radon concentration, given that the action threshold is $4$ pCi$/$L$?$

The decay constant for radon is $7\mathrm{.}6$x$10-3$ hr$-1.$

b$.$ If the radon concentration was above the action threshold, how should the residents

adjust the air exchange rate to reduce the concentration to acceptable levels? $($i$.$e$.$ What

air exchange rate would be needed $($air changes$/$hr$)?)$