I do know some of the ground staff carry paintbrushes and clean the pedestals and instruments as much as possible. I agree that the cleaners have probably been warned off the use of a vacuum in the flight deck however.

'one pound per person per minute'. Its all changed!!!. The 400 goes low flow all packs in cruise. Those experiencing problems should see if 'Hi Flow' helps!!

Nwt
Another intelligent response!!! Provide a vacuum for our pre-flight like the one provided years ago.

It is not dirt or dust but Ozone. Higher latitudes in winter you will be in it. Pax planes normally have ozone scrubbers or something that deals with it.I doubt the freighter does.
In previous life we used to have to fly lower altitudes transcon in US with 737 because it didn't have any system to remove Ozone.

From one of the manufacturers of the scrubbers:

http://www.catalysts.basf.com/Main/e...zone_catalysts

The air at high altitude contains significant levels of ozone. If left unchecked, atmospheric ozone enters aircraft through air conditioning ducts. Ozone exposure is known to cause adverse health effects: Some symptoms attributed to "jet lag" or "air sickness" may actually be caused by ozone. Persons exposed to ozone can experience headaches, fatigue, shortness of breath, chest pains, coughing, and irritation of the eyes, nose or throat.

Now we need to find a cheap way of measuring the Ozone level in flight and if it's higher than safe levels you have likely found the cause for the symptoms.

The ducts and fan impellers' immediate areas do get a large amount of dust buildup which are only cleanable by mx after removing ducts and fans. It seems like a perfect place for bacteria and virus to collect and I've personally had presistent cough and allergy like sysmptoms after replacing these ducts and fans, until I started wearing full face respirator masks. I can guarantee you 100% that there's no maintenace interval program to clean these areas unless they happen to be removed at heavy check for some other reason. These areas are not easy to keep clean requiring disassembly of systems and so it's a design flaw and you have to remember this aircraft was designed in the 80's and there's all kinds of design areas in which it lags way behind when you compare it to today's designs for the same.