According to the VPI (German Pyrotechnic Industry Association), the fine dust particles from fireworks are water-soluble because they consist of soluble salts. Therefore, unlike the fine dust particles generated from traffic, they only remain in the air and in the lungs for a short time.
The fine particles from fireworks contain soluble salts, but no soot, and is also not carcinogenic. Both the soil and the plants absorb these fine dust particles in the form of minerals.