Cascade Impactor

A cascade impactor comprising:

• a series of one or more concentrically-arranged collection stages and a terminating filter or filter adapter stage,
• each collection stage comprising an elongated structure with a cylindrical shape,
• said elongated structure having an open top end and a bottom end containing at least one orifice through which aerosol-containing air flows,
• the walls of said elongated structure having an inner surface and an outer surface and further characterized by a raised portion inside said bottom end,
• said raised portion sized to establish an orifice-to-collection surface distance,
• the outer diameter of said elongated structure being sized to fit within and slidably seal within the inner diameter of the next stage in the series.

A cascade impactor comprising a series of one or more concentrically-arranged collection stages and a terminating filter or filter adapter stage,

• each collection stage comprising an elongated structure with a cylindrical shape,
• said elongated structure having a top end and a bottom end,
• the walls of said elongated structure having an inner surface and an outer surface and further characterized by a first inner diameter, a second inner diameter, a first outer diameter and a second outer diameter,
• the top end of each stage being open and the bottom end being closed with a flat surface,
• said elongated structure further comprising a region wherein the second outer diameter is less than the first outer diameter to form a orifice-containing region,
• and a region wherein the first inner diameter is greater than the second inner diameter forming a step feature,
• the wall of said elongated structure further comprising one or more orifices positioned in said orifice-containing region and perpendicular to said wall and through which aerosol-containing air flows,
• the first outer diameter of said elongated structure being sized to fit within and slidably seal within the first inner diameter of the next stage and rest upon the step feature of said next stage in the series.

A method of simultaneously coating the collection surfaces of an assembled cascade impactor comprising:

• placing a liquid coating material into a compressed air nebulizer,
• connecting said nebulizer to a pressurized container having a release valve connected to the container,
• said container being pressurized up to about 10 times the operating pressure of said nebulizer, connecting the nebulizer to the inlet of said impactor,
• sampling air through said impactor,
• and opening said valve to aerosolize the coating material.