[concerned about politics]

Well, duh! Of course there was higher levels of asbestos in the air -- two huge 110-story buildings built with asbestos insulation just crashed to the ground.

If so, it had to be from smaller nearby buildings.
The original plans for both towers had asbestos in the building plans. The environmentalists had a fit, and the building engineeers had to remove it and replace it with something "safer." That's why the towers burned the way they did. The original plans had them being 2 of the safest buildings ever built.

[FreedomCalls]

This was discussed here two years ago. On one of the towers the asbestos was already in place about 1/2 way up and the other about 1/3 of the way up when the change was made and they ceased to use asbestos. In both cases, the asbestos was well below the point of impact of the aircraft. Both towers did have some asbestos.

[Tymesup]

If I remember correctly, the asbestos used in the construction was different than the stuff that is used for insulation and not the same health risk. Although it appears to be a problem when the building comes down.