Can one collector be temporarily taken out of service

 Civil Engineering
Dust is removed from the airstream of a municipal incinerator by four dust collectors operating in parallel, each handling 1/4 of the total airflow of 200 m³/min. The airstream contains 10 g/m³ of suspended solids. The collector efficiency is 98%, decreasing linearly to 74% as air flow is doubled. If the maximum permissible solids concentration from the combined stack discharge [all 200 m3/min] is 1.0 g/m³, can one collector be temporarily taken out of service by:

(a) overloading the other 3 units [i.e., each of the three handling 1/3 of the total flow], or

(b) by not treating 1/4 of the airflow [i.e., mixing 150 m3/min of treated air with 50 m³/min of untreated air]?