One important consideration is the fact that Lead-214 and Bismuth-214 are electrically charged, singly ionized ions. The other factor that needs to be taken into account is the fact that these reactions occur within an ionization trail that contains hydroxyl radicals and NO2 (the Alpha particles are ejected at 7-8% the speed of light, and the daughter atoms recoil at 10 to 13 million mph). And the final factor that make all this more complex that single atoms floating in nitrogen and oxygen is the fact that air isn't pure, but is often contaminated with volatile organic compounds, particularly indoor air, and SO2.

As a result Lead and bismuth oxide isn't formed. They form clusters of 5 to 8 water molecules and often a few molecules of VOCs. They were measured experimentally, and are 1.2 - 2 nanometers in diameter.

Po-218 is a little different, it can form larger clusters about 15 nm that additionally contain SO2 (if air contains a few ppm of SO2, common in urban and inner city environments), and water molecules. It can also form much smaller clusters of PoOx, 0.5 - 1 nm.

I think I've summarize what I read correctly.

Ref.:

Castleman Jr, A.W., 1991. Consideration of the chemistry of radon progeny. Environmental science & technology, 25(4), pp.730-735.

Hopke, P., 1996. The initial atmospheric behavior of radon decay products. Journal of Radioanalytical and Nuclear Chemistry, 203(2), pp.353-375.