May float in the air. Respiratory system is well equipped with nose hair and cilia to bring dusts back out of the system. Produced when metals are heated to high temperatures and are atomized. They then oxidize in the air and become extremely fine metallic particles which are not handled well by the respiratory system. Metal fume fever is a common disorder in the welding profession.
Smoke is extremely variable in particle size and toxicity.
Health effect depends on hazardous decomposition products and the temperature of the burning materials. Liquids - are materials that adopt the shape of their container. Vapors may present confined space problems or present the physical hazards described earlier. Vapors tend not to re-convenes or settle out. Fog is a prime example.