Most of the $\mathrm{CO}_{2}$ emitted by industrial sources comes from the combustion of fossil fuels, but some is also produced by cement manufacturing and the conversion of limestone $\left(\mathrm{CaCO}_{3}\right)$ to lime $(\mathrm{CaO}):$
$$\mathrm{CaCO}_{3}(s) \rightarrow \mathrm{CaO}(s)+\mathrm{CO}_{2}(g)$$
How many tons of $\mathrm{CO}_{2}$ are produced per ton of lime?