The invention provides methods and apparatuses for removing additional aerosols and in some cases additional particulate matter from a gas stream, wherein a certain portion of such aerosols and particulate matter has already been removed using a primary aerosol and particulate collection device. In some embodiments, the invention includes a method for removing additional aerosols from a gas stream, including passing a gas stream having a plurality of aerosols through a gas duct; removing a first portion of the plurality of the aerosols using a primary aerosol collector; passing the gas steam through a screen; collecting at least a second portion of the plurality of aerosols on the screen; and cleaning a portion of the screen outside of the gas duct. The invention also provides various apparatuses for use in performing the method of the invention.