3.1  General Maintenance

During long-term operation the NAIS should be cleaned every 1 – 3 months due to the deposition of particulate matter inside the instruments.

During the cleaning procedures all parts, which are in contact with the sample and sheath flow, should be thoroughly wiped using delicate task disposable wipes (e.g. Kimberly-Clark Kimtech Science Kimwipes) and alcohol (e.g. 2-propanol). Wipes that get easily worn out and leave fibers should be avoided.

The inlet net and inlet tubing should be cleaned thoroughly in 1 – 3 week intervals to maintain the optimal aerosol sample flow and reduce the amount of dirt settling on the analyzer. The required interval depends on the local aerosol concentrations.

The Venturi flow tubes contain honeycomb flow straightener. These should be checked for obstructions and cleaned carefully with a brush or pressurized air