How much does a forest of smoke weigh?

Last night, spike mused curiously on how much the smoke from the Quebec forest fires weighs. I thought about it for a while and realized that I didn't think I had enough information even to estimate. How much does a particle of smoke weigh? How many particles in the air normally? How many particles per cubic foot are represented by 1 mile visibility? Then spike pointed out that it might be easier to go at it from the other side: how much does a tree weigh and how much of that turns into smoke? We didn't have much information there, either, but the numbers were a little more graspable, so here's what we came up with:

We guessed that the "average" tree weighs about 1000 (10^3) pounds, there are about 10^9 trees burning, that about 1% of a tree's weight turns into smoke, etc, etc. Our final calculation was that there were about 100,000 tons of smoke resulting from those fires, which I actually think represents a dropped zero somewhere, and, obviously some wild guesses. I decided I wanted to know more, so I went to the internet for some numbers that represent real data, even if they still lead to an estimate:
( Cut for slightly more data-driven estimate: )

this happens to you, right? RIGHT?

Ever since I was a kid, I've had this ... thing, where I can't look at or picture sharp things (especially things like thumbtacks or needles jumbled in a box, but also sometimes things like knives or forks) without causing a physical sensation behind my eyes. Is this my eyeballs cringing? I have no idea! Does this happen to you? What about other weird, difficult-to-explain physical sensations?