Carbon monoxide $(CO)$ is a gas emitted by poorly functioning furnaces and wood fireplaces. It is a

poisonous gas because it binds to your hemoglobin and prevents oxygen from binding. Symptoms

include headache, dizziness, confusion, nausea, loss of consciousness, and eventually death at high

enough concentrations. Consider a living room with a wood burning stove that emits $CO$ at rate of

$0\mathrm{.}8gh{r}^{-1}.$ The room volume is $30m^3$ and the ventilation rate $($air changes per hour$)$ is $2h{r}^{-1}.$

a$)$ Calculate the steady state concentration of $CO$ in the air in units of $mg{m}^{-3}.$

b$)$ Convert the steady state concentration to units of ppm$.$

c$)$ Imagine that the stove suddenly starts emitting at $1\mathrm{.}6gh{r}^{-1}$ because the flue is partially

blocked. Estimate how long it will take to reach the new steady state $CO$ concentration $($i$.$e$.$

calculate the characteristic time$).$ Express your answer in hours.