c += concentration(s, t) ▷ Equation 2/3 but also computational cost. The latter affects the accuracy of approximating continuous emissions by discrete puffs; smaller values yield better approximation at the expense of higher computational costs. In our model implementation (refer to Algorithm 1 and 2), these two parameters collectively determine the computational cost, as the runtime for pairs (∆t 1 , ∆p 1 ) and (∆t 2 , ∆p 2 ) is similar if ∆t