I was just rereading his blog and it became clear where he gets his figure for 0.008 ug/l Al in rainwater. He has taken the upper figure 8 ug/m3 for air converted it to litres. However he fails to understand that the content of solids in rainwater is not directly proportional to what is in the air. I suggest he reads around "Rainwater Scavenging" as different types if precipitation will contain differing proportions of solids. I would suggest that a move to air sampling may be called for and maybe hire a sampler and set it up near a CEH/DEFRA system to validate their results (any interested group can do this)
I note he has addressed the TMA issue. However his claim now is that a 15% suspension of TMA in hexane is added at a proportion of 22% of the fuel. That means that fuel contains 3.3% TMA. Jay has already demonstrated that TMA will produce a lesser amount of Aluminium oxide therefore for every metric tonne of fuel burned less than 33kg of aluminium oxide will be produced. I would suggest that at that quantity it would not look like the long trails in the sky (I have no idea how much fuel is burned per mile).
Where does he come up with this stuff? Not only would it produce miniscule amounts of aluminum oxide, TMA in hexane is still a pyrophoric and it will still crystalize below 20 C. Not exactly properties one would want in an additive for jet fuel used in commercial airliners, or any aircraft for that matter.