We have just arrived in Luang Prabang by boat from Chiang Khong. We stayed at the Anantara where the smoke situation was not good (great hotel though!) but the smoke on the way down was really awful. For two days we sat on the boat with scarves wrapped around our faces to try and keep out the smoke. It was difficult to breathe at times and for a large part of the journey the visibility was so bad you could barely see across the Mekong. The situation in LP is a bit better but it is still smokey with v. poor visibility.
For anyone contemplating a similar journey I would think twice as, in the absence of any rain, i doubt the situation will get any better any time soon.
This is the first time I have been looking forward to Bangkok for the fresh air!

sad report....hope you enjoy LP in spite of the smoke...

My son is in Masan South Korea. He said the polution has been really bad. On Sunday he said that some kind of yellow dust was so thick you could hardly see threw it. The Koreans he works with said it was the worse they have ever seen. Supposedly it was coming from China.

Whats the smoke situation like in Chaing Mai and Chiang Rai?

I'm in Chiang Mai right now. It's pretty hazy--you can't really see Doi Suthep from the city--but i haven't needed to wrap a scarf around my face or anything. Basically, i don't think it's that bad, but i'm a New Yorker so my standards might be different. It's HOT, though.

The smoke in LP is getting better, but it is still very hazy. The smoke got considerably worse as we travelled down river and was at its worse from Pakbeng where the whole mountainside on the opposite bank was alight and black ash was falling down everywhere. from pakbeng to LP the visibility was so bad that you could barely see from one bank of the Mekong to the other (100 meters). the situation in LP is getting better day by day and although it is still hazy, we did see some blue sky yesterday.