Cyclone efficiency logic

Consider a cyclone designed for treating particle$-$laden gas from an industrial process, The uncontrolled source emits particles that are distributed broadly over the size range $1-30m.$ Overall, the cyclone exhibits efficiency for this source of $90\%$ on a mass basis. The suggestion is made that the treatment efficiency can be improved by adding a

second cyclone, identical to the first, in series $($i$.$e$.,$ the industrial emissions would travel through the first cyclone and the effluent of the first cyclone would travel through the second, identical cyclone$).$ Approximately what overall particle mass removal efficiency would you expect from the two units in series? Explain your answer.