Every camp in Kuwait had one and most fob used one once area became secure. Millions upon millions of plastic water bottles were the makers of the black smoke along with tires. When advancing you never seen much but when you stayed on location a few days waiting for objectives the trash piled up and was burned. I am sure the oil wells that were set on fire did not help anyone breath better. The guys from the first Gulf was had more well fires to deal with but much less exposure to burn pits.
My guess is this will be this generations Agent orange.
The blowing sand/dust alone really did not help anyone's lungs. Take it from someone that ran marathons, had a low 17 5K to someone that got winded doing a near 20 min PFT. Just old age catching up at 45 I guess. Waugh!