To provide a method and an apparatus for drastically reducing suspended particulate matter (SPM), or the like, in exhaust gas from an existing internal-combustion engine or dust in the air discharged from an air tool.

The apparatus is constituted so that the exhaust gas from the internal-combustion engine or the air discharged from the air tool is not discharged directly to the atmosphere but is made to pass through the water in a water tank to mix SPM, or the like, in the exhaust gas and the dust in the discharged air with the water. According to this apparatus, the water tank can be maintained very easily at a low cost, only the water in the water tank is to be exchanged or replenished, and atmospheric pollution can be reduced drastically.