Are you saying that none of the Saharan particles are small enough to
cause this effect?

I would have thought that at the end of a Saharan dust spell, such as
occurred yesterday, the final particles to settle out of suspension
would be the finest particles which, if small enough, could have
contributed to the observed discolouration.

What you say is quite plausible, and may well have contributed to the
reddening in the way you describe. Most Saharan dust seems ( to my eyes) to
cause a milkiness to the sky, which indicates an equal scattering of all
wavelengths similar to Cs or fog or very thin low St, but since there must be a
distribution of particle sizes there could well be some small stuff as well.
But the phenomenon of the reddish moon is so common I can't quite
understand why it has caused so much comment and so many exotic explanations
invoked. It affects the sun, too. I remember an occasion in Dec 2000 when,
with a cloudless sky, the sun disappeared from view as a dim red globe, several
degrees above the horizon. It was nice to watch but not exactly noteworthy. I
would say it is less commonly observed than, say, 40 yrs ago, because the
atmosphere is less smoky these days.

Tudor Hughes, Warlingham, Surrey.